Energy Feasibility Study DRAFT - LocalNexus – Building …localnexus.org/wp-content/uploads/2016/02/Energy... · · 2016-02-15Energy Feasibility Study DRAFT López-Avilés, A

February 2016

Food-Energy-Water Local Nexus Network for

Redistributed Manufacturing:

Energy Feasibility Study DRAFT

López-Avilés, A. and Leach, M., Centre for Environmental Strategy,

University of Surrey

Energy Feasibility Study DRAFT report

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Executive Summary

The Food-Energy-Water Local Nexus Network (LNN) for redistributed manufacturing focuses on the

development of local nexuses of food manufacturing and energy and water supply which may

provide opportunities for rationally customising resource utilisation, production, and consumption

while contributing to the shared prosperity between business and community, and between

human society and natural ecosystems.

This network involves a multidisciplinary academic team across six UK universities working with

representative stakeholders that will study the local nexuses along four research themes:

engineering, business, policy and society, and systems integration. Two case study locales provide a

common background for different research themes to interact and integrate, and will serve

purposes ranging from collection of empirical data to stakeholder engagement. These two case

studies represent respectively situations of “new development”, (Northstowe, Cambridgeshire,

where opportunities exist to introduce a new food, energy and water system), and “retrofitting”

(Oxford, where an existing system is to be changed to benefit from the paradigm of local nexuses).

The work will be developed through six inter-related feasibility projects. This DRAFT report covers

the work undertaken to date within the Energy Feasibility Study.

The specific objectives of the Energy Feasibility study are:

1. Assess requirements for energy supply (electricity and heat of different qualities) to

localised food systems (e.g. production, storage), including typical temporal (diurnal

and seasonal) variations

2. Assess opportunities for energy integration across the local supply and production

chains (e.g. CO2 emissions to be used in green-houses to aid tomatoes ripen, re-use

heat loss from cooling down after evaporation etc.).

3. Assess potential for energy recovery from waste arisings from food production

across the local supply chain, plus arisings from local water/wastewater treatment

systems

4. Develop local energy system scenarios, including other potential users

5. Evaluate energy generation and storage technologies suitable for implementing the

scenarios: efficiency, cost effectiveness, safety, and environmental impact

Based on the objectives above, existing literature was reviewed on the Nexus and the linkages

between Energy and Water, Energy and Food etc. and this is summarised below. A review of

existing academic and grey literature and data on energy use for the production of two chosen food

products: tomato paste and bread, is also detailed below. Work is currently ongoing for the energy

system scenario development and analysis.


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Contents

Executive Summary ................................................................................................................................ 2

1. Background to the Food-Energy-Water Local Nexus Network for Redistributed Manufacturing

project ..................................................................................................................................................... 6

1.1. LNN Energy Feasibility Study ................................................................................................... 6

2. Introduction to the Water-Energy-Food Nexus............................................................................. 7

2.1. Water-Energy linkages ............................................................................................................ 8

2.2. Energy-Water linkages ............................................................................................................ 9

2.3. Energy-Food linkages ............................................................................................................ 10

2.4. Water-Food linkages ............................................................................................................. 11

3. Energy involved in industrial food processing: the case of tomato paste ................................. 11

3.1. Energy and CO2 emissions of vegetable oils ......................................................................... 12

3.2. Energy and CO2 emissions of tomato paste .......................................................................... 14

3.2.1. Energy and CO2 emissions of tomato paste in Europe, Canada and other countries ... 14

3.2.2. Energy and CO2 emissions of tomatoes in the UK ........................................................ 16

3.3. Opportunities for energy integration across the local supply and production chains of

tomato paste production in California .................................................................................. 17

3.4. Opportunities for tomato paste production in the UK ......................................................... 18

3.5. Example of tomato nurseries, Worcestershire, and interview with local tomato grower ... 19

3.5.1. Water .................................................................................................................................. 20

3.5.2. Energy ................................................................................................................................. 21

3.5.3. Waste and waste water, and energy from waste ............................................................... 23

3.5.4. Juice business model and general aspects.......................................................................... 25

4. Energy involved in industrial food processing: the case of bread .............................................. 26

4.1. Introduction .......................................................................................................................... 26

4.2. Emissions linked to the production of wheat for bread ....................................................... 26

4.3. Bread making and energy requirements .............................................................................. 27

4.4. Studies/data available on energy involved in bread making in the UK ................................ 28

4.4.1. Energy used in food manufacturing in the UK .............................................................. 28

4.4.2. Energy and green-house gas (GHG) emissions of growing wheat in the UK ................ 29

4.4.3. Energy and green-house gas (GHG) emissions associated with the industrial bakery

sector in the UK ............................................................................................................. 30


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4.4.4. Energy intensities of bread in the UK ........................................................................... 31

4.4.5. Emissions associated with bread in the UK................................................................... 35

4.4.6. Energy efficiencies in the bakery sector ....................................................................... 35

4.4.7. Summary of the energy implications of making bread in the UK ................................. 36

4.4.8. Wastes and by-products from the bread supply chain and potential for energy

generation ..................................................................................................................................... 37

4.5. Interviews with local mills and bakeries ............................................................................... 38

4.5.1. A Mill, Oxfordshire ........................................................................................................ 38

4.5.2. B Mill, Oxfordshire ........................................................................................................ 40

4.5.3. Village bakery and local bakery facility, Oxfordshire .................................................... 41

5 Summary of findings relevant to the Energy Feasibility Study from one-to-one interviews .... 44

5.1. Areas for further investigation according to interviews and site visits ................................ 45

5.1.1. Tomato paste case study .............................................................................................. 45

5.1.2. Bread case study: mills .................................................................................................. 45

5.1.3. Bread case study: bakery shop and local bakery facility ............................................... 45

6. Stakeholder engagement ............................................................................................................. 46

6.1. Feedback from stakeholders workshops .............................................................................. 46

7. Detailed Energy investigation: local energy system scenarios (including other potential users)

(section under development) .............................................................................................................. 48

8. Evaluate energy generation and storage technologies suitable for scenarios (efficiency, cost

effectiveness, safety, and environmental impact) (section under development) ............................. 49

9. Conclusions ................................................................................................................................... 49

References ............................................................................................................................................ 51

Appendix A ........................................................................................................................................... 56


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1. Background to the Food-Energy-Water Local Nexus

Network for Redistributed Manufacturing project

The Local Nexus Network (LNN) is one of six 24-month research networks on Redistributed

Manufacturing (RDM) funded by the EPSRC and the ESRC which started in early 2015.

The LNN focuses on the development of local nexuses of food manufacturing and energy and water

supply, which may provide opportunities for rationally customising resource utilisation, production,

and consumption to meet the services required within a local context while contributing to the

shared prosperity between business and community and between human society and natural

ecosystems. This represents a complex and significant transition, which requires “smart”

engineering (smaller scale technologies, integrated processes), and driving forces from businesses,

communities and policy makers to turn the potential of local nexuses into an economic and social

reality.

This network involves a multidisciplinary academic team involving six UK universities and interacting

with representative stakeholders. This network will study the local nexuses along four research

themes: engineering, business, policy and society, and systems integration, supported by two case

studies representing respectively situations of “new development”, (Northstowe, Cambridgeshire,

where opportunities exist to introduce a new food, energy and water system), and “retrofitting”

(Oxford, where an existing system is to be changed to benefit from the paradigm of local nexuses).

These case study locales will provide a common background for different research themes to

interact and integrate and will serve purposes ranging from collection of empirical data to

stakeholder engagement. The total space of 3 sectors, 4 research themes and 2 types of locales is

explored through six inter-related feasibility projects. This draft report covers the work undertaken

to date within the Energy Feasibility Study.

1.1. LNN Energy Feasibility Study

The Oxford case study was used for background empirical data collection and to develop new

thinking around localised production of food and energy supply for local food systems.

The specific objectives of the Energy Feasibility study are:

1. Assess requirements for energy supply (electricity and heat of different qualities) to

localised food systems (e.g. production, storage), including typical temporal (diurnal

and seasonal) variations

2. Assess opportunities for energy integration across the local supply and production

chains (e.g. CO2 emissions to be used in green-houses to aid tomatoes ripen, re-use

heat loss from cooling down after evaporation etc.).


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3. Assess potential for energy recovery from waste arisings from food production

across the local supply chain, plus arisings from local water/wastewater treatment

systems

4. Develop local energy system scenarios, including other potential users

5. Evaluate energy generation and storage technologies suitable for implementing the

scenarios: efficiency, cost effectiveness, safety, and environmental impact

Based on the objectives above which are outlined in the Energy Feasibility Study Profile, existing

literature was reviewed on the Nexus and the linkages between Energy and Water, Energy and Food

etc. and this is summarised below. A review of existing academic and grey literature and data on

energy use for the production of two chosen food products: tomato paste and bread, is also

included below. Work is currently ongoing for the energy system scenario development and

analysis.

2. Introduction to the Water-Energy-Food Nexus

The increasing water demands resulting from agriculture and industrial processes, lifestyle changes

and population growth are resulting in rising financial and environmental costs. More energy and

chemicals are increasingly being used to make water potable, to distribute it and to protect against

more frequent and damaging flooding in all countries. Climate change predictions point to more

extremes both in terms of water scarcity and flooding in many regions of the world. Drought-

affected areas will increase in extent, but rainfall concentrated in wet season, and intense

precipitation events will increase flood risk. The atmosphere and oceans have warmed, the amount

of snow and ice have diminished, sea level has risen and the concentrations of GHGs have increased,

and further emissions of GHGs will cause more warming and changes in all components of the

climate system (IPCC, 2013 and 2014).

Furthermore, water and energy-intensive industrial and agricultural practices are also likely to

increase in order to meet demand for goods and food all over the world, thus existing water

resources are under pressure from ever-increasing competing uses. According to McKinsey &

Company (2009) agriculture accounts for 31% (3100 billion m3) of global water withdrawals and

these are expected to increase to 4500 billion m3 by 2030. The OECD (2010) estimates that

agriculture is the major user of water ‘accounting for about 70% of the World’s freshwater

withdrawals and over 40% of OECD countries’ total water withdrawals’. Whichever figure is chosen,

what is clear is that agriculture accounts for a significant share of the World’s freshwater use, and

globally it is estimated that approximately 50% more food will need to be produced by 2030, and

production will need to be doubled by 2050. This will have to be done with less water due to climate

change impacts and the pressures of competing water uses linked to urbanisation and


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industrialisation (OECD, 2010), with population growth and global trade adding to the complexities

and multidimensionality of the Nexus (Mohtar and Daher, 2012).

According to Professor John Beddington (2009) “a ‘perfect storm’ of problems around simultaneous

water, energy and food shortages will lead to public unrest and international conflict in the near

future unless 50% more food, 50% more energy and 30% more freshwater are available by 2030,

whilst mitigating and adapting to climate change”.

Given the emerging issues of insecurity in terms of energy and food supply across the world, both

the energy and agriculture/agro-industrial sectors are under pressure to meet future demand while

producing more cheaply. Hence, society faces real challenges to minimise emissions of Green-House

Gases (GHGs), adapt to climate change impacts and to satisfy food, water and energy demands while

reducing our environmental footprint.

Ringler et al., (2013) recognise that the inter-connections between the Water, Energy, Land and

Food sectors has become more apparent as a result of pressures on natural resources and

emphasise the need for all nexus analyses to consider human well-being and environmental

outcomes in addition to assessing benefits across the three sectors. It has been recognised also that

many of the issues that the Water-Energy-Food Nexus Agenda aims to address are not new and have

faced significant barriers to progress in the past due to political economy challenges, overambitious

aims and the complexity of working across disciplines, which could again lead to the downfall of the

Nexus agenda (Leck et al., 2015). However the same authors acknowledge that the increasing use of

resources across the world, together with better modelling and assessment tools to study

interdependencies between the three sectors can create the momentum to overcome old barriers.

In relation to assessment tools for the study of Nexus relationships, after a review of integrated

resource assessment and modelling literature, Bazilian et al., (2011) confirmed that existing

analytical and decision-making tools available are for a single resource/system, thus justifying the

need for a new Nexus modelling framework, which they present as the Climate, Land, Energy and

Water (CLEW) modelling framework. Developed by the International Atomic Energy Agency CLEW

was designed to map key Nexus relationships (including in developing countries), and also aims to

assist decision-making, policy assessment and harmonisation, technology assessments, and scenario

development.

Some of the Nexus linkages between the three sectors are summarised below.

2.1. Water-Energy linkages

Energy is required for pumping water from aquifers, for distributing fresh water, drainage from

roads and fields, for collecting foul water, desalination, water treatment, distribution in farms and

cities, irrigation, sewage treatment etc.

The water sector is a large consumer of energy, for example via desalination, ranging from reverse

osmosis plants that consume 4-6kWh/m3 of treated water versus 21-58kWh/m3 for multistage flash

(MSF distillation is a water desalination process that distils sea water by flashing a portion of the

water into steam in multiple stages - mainly employed for large-scale, thermal desalination plants


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where thermal energy is available in the form of low-pressure steam (>2 bar a), e.g. in combination

with thermal power plants or industrial complexes (http://www.wabag.com/performance-

range/processes-and-technologies/msf-multi-stage-flash/) –see Semiat, 2008).

However it should be noted that desalination is more energy intensive than other methods of

producing potable water. Groundwater supply uses about 30% more electricity on a unit basis than

supply from surface water (i.e. rivers, lakes and reservoirs) due to the pumping element of ground

water abstraction that has been estimated to be 2100 kW/h per million gallons (i.e. 3,785,412 litres),

plus water transport (WEF, 2011).

The energy inputs of transporting water are often overlooked. Generic energy requirements in

transporting water (i.e. energy in kWh required to deliver 1m3 of clean water) have been summarised

in the table below from a study by the World Economic Forum (see WEF, 2011):

Lake or river 0.37 kWh/m3

Groundwater 0.48 kWh/m3

Wastewater treatment 0.62-0.87 kWh/m3

Wastewater re-use 1-2.5 kWh/m3

Seawater 2.58-8.5 kWh/m3

The distance that water needs to travel is also a major factor to consider when looking at energy

inputs.

2.2. Energy-Water linkages

The opposite is also true, the energy sector itself is a major water consumer with the ‘largest

withdrawal of water in the USA and most industrialised countries going for power plant cooling’ (see

WEF, 2011). For example, in 2005, this amounted to half of all withdrawals (49%) in the USA (CSS,

2014).

Nuclear is the highest water demanding thermoelectric technology although other energy sources

such as biofuels (see under the Energy-Food linkages of the nexus too) have also been reported as

the most water-intensive fuel sources (one or two orders of magnitude greater than that of

alternative sources of liquid fuels) in contrast with solar and wind energy that can help meet

increasing energy demands without applying more pressure on the Nexus (see Mielke et al., 2010).

In relation to the water footprint of different types of biomass and the linkages between energy and

food (see 1.1.3 below), Gerbens-Leenes et al., (2009) looked at 15 crops including one tree species

and a bio-energy crop, and compared these and food crops in terms of their water footprint in

relation with fossil fuels. The research highlights the controversy of whether to use land and water

for food or energy crops. In terms of water use, this paper indicates that nuclear and fossil fuels use

less water (in their operational phases only) than many food crops, although a counterargument can

be made that the choice of food crops and regions to grow them which is used for this study may not


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be the best for a biomass study comparing bio-energy crops with other energy sources such as wind,

nuclear, natural gas, coal, solar, oil, solar thermal and hydro.

In relation to the linkages Water-Food (and land), ‘thirsty’ crops that can be used as fuel (e.g. corn)

are often grown as food because of benefits such as high yields, nutritional value or income-

generation, despite their high land and water footprints. However, Gerbens-Leenes et al., (2009)

and Jordaan et al., (2013) point out that increasing the contribution of energy from biomass to meet

energy security goals will mean larger consumption of fresh water and competition for water and

land between energy and food crops.

Thus, as highlighted by Bazilian et al., (2011) single resource tools such as water footprinting are not

a good way to assess the suitability or not of biomass because they ignore Nexus and geographical

linkages such as whether there is competition between food crops and other land uses, and /or

whether water footprint is an issue at all or not in a particular region.

The issue of boundaries is also problematic when making comparative studies. Gerbens-Leenes et

al., (2009), for example, consider the water footprint of mining operations only for uranium, gas,

coal etc. therefore limiting the comparative study to the first stages of the supply chain, but huge

amounts of water are lost through evaporation in later stages, for example in the cooling down

process in nuclear and fossil fuel power stations.

Other studies on energy and water focus specifically on biomass. King et al., (2013) suggests that

water availability is the most important climatic change to consider in the design of future bioenergy

systems. Despite the variations on bioenergy productivity in relation to water availability, biomass

has an advantage over other energy sources in that it favours small scale decentralised systems

where, unlike in huge power stations, water is not needed for cooling, or where water /steam used

for cooling -if any- is re-circulated in a close circuit and can be then used for heating (combined heat

and power CHP plants).

2.3. Energy-Food linkages

In relation to energy and food (and land), the prices of food are linked to the global price of oil (i.e.

see for example food prices soaring globally between 2006 and 2008). Transporting food around the

world makes food dependent on oil as the main energy source. The controversy arises with

alternatives to fossil fuels such as biofuels are considered as discussed more extensively above under

Energy-Water linkages.

Policies that aim to diversify the sources of energy away from oil (e.g. the drive to turn corn into

ethanol in the USA, softwood and sugarcane into biodiesel in Brazil and Mauritius) mean that food

products are being transformed into fuel, and more and more arable land is being used for biofuel

production in competition with growing food. Mohtar and Daher (2012) point out the controversy

that biodiesels generate also in relation to water consumption and soil and water degradation

associated with the excessive use of fertilizers.


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2.4. Water-Food linkages

According to a study by the ‘2030 Water Resources Group’ of businesses and water stakeholders,

‘agriculture accounts for 31% (3100 billion m3) of global water withdrawals, which is expected to

increase to 4500 billion m3 by 2030’ (McKinsey & Company, 2009).

A Study by the Organisation for Economic Co-operation and Development indicates that agriculture

is the major user of water, accounting for about 70% of the world’s freshwater withdrawals and over

40% of OECD countries’ total water withdrawals. This study also indicates 50% more food will need

to be produced up to 2030, and production will need to be doubled by 2050 with less water

available due to growing pressures from urbanisation, industrialisation and climate change (OECD,

2010).

A number of academics (e.g. Allan (1998), Allan (2012), Hoekstra (2003), Chapagain et al., (2006),

Mekonnen and Hoekstra (2011)) have worked extensively in defining ‘green water’ (rain-fed) and

‘blue water’ (surface and groundwater), and calculating volumes of both green and blue water

across the world to ascertain the trade of ‘virtual water’ embedded in agricultural and industrial

products. Different countries have different water productivity (output per unit of water volume

consumed), so some countries with high water productivity have a competitive advantage, while

others have a competitive disadvantage that can lead to water being ‘imported’ via importing food

goods. This is the case in many Middle East countries which import nearly the totality of their food

(and water), thus creating political and social dependency on other regions of the world. The

complexity of these dependencies have led to some scholars to emphasise the need to globally grow

food products maximising ‘green water’ and saving blue water, viewing water as a global resource

that should be saved by all countries wherever possible for food production (Mohtar and Daher,

2012).

3. Energy involved in industrial food processing: the case

of tomato paste

After setting the linkages between Energy and Food and Energy and Water above, this section will

focus on reviewing existing literature on the energy involved in producing tomato paste, which is

one of the three chosen food products to be investigated under the LNN project. Although the focus

of the Energy Feasibility study is on the linkage between Energy and Food, water can contribute to

save energy by re-using the heat stored in water and steam during manufacturing processes, hence

the importance of considering the complete Nexus in the Energy Feasibility study.

Integrating renewable sources of energy into the industrial processes is the subject of research by

Hummel et al., (2013) that examined the opportunities for solar thermal energy in the supply of

process heat (for temperatures between 30 and 150˚C), including its economic feasibility. The study

looked at various industrial processes under different economic and climatic conditions, and

indicates that solar thermal systems have the potential to reduce fossil fuel inputs but are currently

long-term investments with pay-back periods between 8 and 12 years, and longer, even after


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including current subsidies available in Austria. The main reason found for this long pay-back period

is the low price of fossil fuels, while the economic feasibility of solar thermal systems also depends

on geographical and climatic conditions. The work by Hummel et al., also indicates that lower

process temperatures make solar thermal systems more efficient, while waste heat recovery

(another avenue to reduce energy inputs) reduces energy demand from the solar thermal system,

thus making the solar systems less efficient in economic terms.

Reducing fossil fuel inputs via waste heat recovery and re-use within a product’s processing phases is

the subject of various investigations and will be examined in relation to tomato commodities below.

3.1. Energy and CO2 emissions of vegetable oils

Although industrial processes can be energy intensive, studies that looked at the energy and CO2

emissions of some vegetable products have found that agriculture is responsible for most of the

emissions to the atmosphere. Özilgen and Sorgüven (2011) investigated the production of soybean,

sunflower, and olive oils and found that most of the energy used and CO2 emissions for these

products were related to the agricultural phases as a result of excessive use of fertilizers, and the

consumption of diesel as the dominant source of exergy (high quality energy) and total energy

(addition of exergy and anergy -wasted energy with less capacity to perform work). Figure 1 after

Özilgen and Sorgüven (2011) compares cumulative energy consumption (CEnC) and cumulative

exergy consumption (CExC) in the production of oil from one ton of olives, soybeans and sunflower

seeds. Most energy and exergy is used in agriculture, followed by packaging. Figure 2 illustrates the

carbon footprints of these three types of oils with soya having the most CO2 emissions per ton of

seeds due to the intensive use of fertilizers to grow this crop and despite the olive oil production

process being the most energy intensive process. The paper argues that better agricultural practices

and biodiesels from renewable sources can help in reducing exergy use.


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Figure 1 Comparison of the cumulative energy and exergy consumptions to produce oil from one ton

of olives, soybeans and sunflower seeds. Source: Özilgen and Sorgüven (2011)

Figure 2 Comparison of the CO2 emissions to produce oil from one ton of olives, soybeans and

sunflower seeds. Source: Özilgen and Sorgüven (2011)


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3.2. Energy and CO2 emissions of tomato paste

As highlighted in the LNN Initial Research Note on Tomato Paste1, the variety of tomatoes used for

tomato paste are harder in consistency allowing mechanical harvesting and transportation, are

grown outdoors and are generally irrigated. In relation to irrigation, substantial amounts of energy

may be required for pumping water from the ground or surface water body directly for irrigation,

and also for pumping from the ground or water body, treatment and distribution through the pipes

network for irrigation, if water comes from a centralised water supply organisation.

Large scale tomato paste processing plants work intensively (typically 24 hours a day during the

tomato season), first sorting and washing tomatoes mechanically harvested. Energy is required for

the mechanical collection and transportation processes, and for treating and pumping water for

washing tomatoes. Energy requirements in some of the above phases are reduced in small scale and

artisanal production lines where some of the processes are done by hand.

Tomatoes are then crushed and heated to form a pulp. This pulp is further heated to a hot (98-

100°C), or cold (60°C) break that results in a more or less viscous paste respectively. These phases

require substantial energy inputs. The pulp is put through screens with some energy input in this

process, and then a vacuum evaporator is used to thicken the paste, which is subsequently sterilised

and rapidly cooled.

Finally in the production process, wastage is often dried and used to feed dairy cattle, for pet food or

is sent to landfill, thus, there is also potential for this waste to be used to feed decentralised

combined heat and power plants (CHPs) to generate energy locally.

3.2.1. Energy and CO2 emissions of tomato paste in Europe, Canada and other countries

Most of the above processing phases for tomato paste production are energy intensive. Karakaya

and Özilgen (2011) studied the energy and CO2 emissions involved in the production of fresh, paste,

whole-peeled, diced, and juiced tomatoes in Turkey including packaging, transportation, and waste

management. This comparative study found that the energy used to make tomato paste

(understood in this work as tomato pulped and then concentrated in multi-effect evaporators) is

twofold that of producing and packaging fresh tomatoes, while for juice the increase is five times,

and for peeled or diced-tomatoes the energy use increases by seven times the energy of processing

the same amount of fresh tomatoes. CO2 emissions were calculated to be 189.4 kg of CO2/ton (Kg/t)

for fresh tomatoes with retail packaging, and very similar for tomato paste. Emissions of peeled or

diced tomatoes increased twofold, while emissions of juiced tomatoes increased threefold.

As with the study by Özilgen and Sorgüven (2011) about vegetable oils, the Karakaya and Özilgen

(2011) study found that chemical fertilizers and transport are the main contributors to CO2 emissions

but that these also depend on the energy source used in the processing, with natural gas generating

relatively fewer emissions than electric power. This study of tomato products also found that energy

use is strongly linked to the amount of water content of the final product. Although evaporation for

1 LNN Initial Research Note on Tomato Paste by Julian Cottee, August 2015


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tomato paste is energy intensive, the study concludes that because the mass of product to be

transported is reduced in the case of tomato paste, the total amount the energy used for paste is

relatively less than for processed whole-peeled, diced and juiced tomatoes.

Manfredi and Vignali (2014) work analyses the life cycle (LCA) of 700 g tomato puree packaged in a

glass jar as a reference product and its production in northern Italy including the cultivation,

processing, packaging and transportation phases. The study aims to identify potential

improvements in each phase by looking comprehensively at all operations related to each of these

phases, for example from land preparation to post-harvest processes in cultivation, and all transport

involved in the supply chain of tomato puree. Farmers and the Italian processing company provided

primary data and Ecoinvent v2.2 was used for secondary data. The water footprint of growing and

processing tomatoes into puree was also calculated.

Similar to other studies (e.g. Özilgen and Sorgüven (2011) and Karakaya and Özilgen (2011)), the

Manfredi and Vignali study found that fertilizers cause the largest environmental burdens, and thus

the cultivation phase was found to have higher environmental impacts than the transportation and

processing phases as a result of the use of fertilizers (eutrophication), pesticides and diesel.

In Manfredi and Vignali’s study, packaging required large amounts of energy for its production and

was found to account for a large part of the environmental impacts of the tomato puree life cycle, so

improvements proposed include reducing the weight of the glass jars (the most common way of

packaging puree in Italy).

In relation to the processing phase, the industrial operations detailed in this study relate to Emilia

Romagna company and are defined as a ‘standardized filling line where puree is filled into glass jars

that then are pasteurized, labelled and packaged in carton trays, before being sent to warehouses

ready to be delivered to clients in Italy’. Impacts of the processing phase are due to the amount of

electricity and natural gas used in pasteurization and concentration of the tomato puree.

In the Manfredi and Vignali’s case study, transport to the retailers contributes to environmental

impacts quite significantly too and so improvements are reported to be possible by reducing the

distance to travel and by optimizing energy use. Other improvement proposed is the use of organic

fertilizers instead of mineral ones in the cultivation phase.

Kissinger in Boye (2015) dedicates Chapter 2 of this book to the case of tomatoes and tomato

products in Canada, assessing the biophysical footprint of this functional food, including its carbon

and land footprints. According to this study based on previous work by the author, the average

carbon footprint of imported tomatoes in Canada is over 400 grams of CO2 per kilogram of tomato.

The carbon footprint of imported tomatoes from Mexico is reported as 750 grams of CO2 per

kilogram of tomato (out of which 540 grams are associated with transportation by truck), compared

with 400 grams of CO2 per kilogram of tomato (out of which 130 grams are linked to transportation

by boat) if the tomatoes are imported from southern Spain. If shipped by air, the Spanish tomatoes

footprint is estimated to increase to 5240 grams (5.24 Kg) of CO2 per kilogram of tomato. The study

also reports differences in the carbon footprint of the same type of tomatoes within the same

country (e.g. Spain), depending on the study and production conditions.


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The land footprint (crop and energy land) of different tomato products in Canada is reported as 1.24

global m2per kg of fresh tomatoes, 2.1 gm2/kg of processed tomatoes, and up to 6.7 gm2/kg of

ketchup. The study compares the carbon and land footprints for tomatoes (and other products) in

different countries, paying attention to the comparison between fresh tomatoes grown in California

and imported to Canada, versus tomatoes grown in Ontario, Canada, in green-houses. The study

finds that shipping tomatoes from California to Canada can help reduce the carbon footprint of

Canada, even though there is energy involved in the tomatoes transportation, and even though the

study also reports that Ontario’s green-house tomato yields are up to 20 times higher than the yields

of field tomatoes grown in California.

The author concludes that the land (including different production systems) and carbon footprints of

functional foods such as tomatoes (including the energy and carbon footprint along the product’s

full life cycle) have to be considered when looking at the long-term sustainability of the products.

Climate, availability of water and land, and the technological and development conditions of the

region/country all influence the ecological footprint of the food product.

Studies of small scale tomato processing industries / operations appear to be rarer, although some

studies exist on the energy use of small scale tomato paste production in developing countries, for

example Abubakar et al., (2010) in Nigeria. This study looks at energy use and production data for a

four year period which shows inconsistencies in the consumption of diesel (98% of the energy source

used in these industries) between these years pointing to leakages and/or malfunctions. The study

is incomplete because no energy data were available in the industries examined for the

manufacturing, transportation and repairs phases, which highlights the difficulties for resource

assessments in some businesses and geographies.

3.2.2. Energy and CO2 emissions of tomatoes in the UK

In the UK, the Department for Environment Food and Rural Affairs (DEFRA) commissioned a study by

Cranfield University that using Life Cycle Assessment (LCA) models the resource use and

environmental impacts of 10 common agricultural and horticultural commodities including

tomatoes, wheat and poultry meat (see Williams et al., 2006). The study included primary resources

such as coal, oil and mined ore as inputs for all commodities, as well as all farm production

supporting activities were also included. The study also differentiated among different varieties of

the same commodity, for example, loose and on-the-vine tomatoes nationally produced in the

correct proportion.

In relation to tomatoes, the study found that ‘about 97% of the energy used in tomato production is

for heating and lighting to extend the growing season’. The lowest yielding tomatoes are organic on-

the-vine tomatoes (yield 75% of non-organic) and they incur up to six times more environmental

burdens than the highest yielding tomatoes -non-organic loose classic or beefsteak tomatoes. These

incur the lowest environmental burdens. This is because the amount of energy used is the same for

all tomato production systems per unit area.


17

In the case of tomatoes, the DEFRA study found that tomato burdens can be reduced by 70% if the

the proportion of Combined Heat at Power (25% in 2006) increased nationally to 100%.

Other important findings of the DEFRA study are that in agriculture (unlike in other industries)

nitrogen, and also methane, dominate the emissions, and that nitrogen fluxes also cause

eutrophication and acidification. Hence most environmental burdens from agriculture are linked to

the nitrogen cycle. The study also reports that for organic production, more land is always required

(65% to 200% extra). The model used for this study can be accessed via the Cranfield University web

site at www.silsoe.cranfield.ac.uk (then search for IS0205 and LCA) and www.defra.gov.uk.

3.3. Opportunities for energy integration across the local supply and

production chains of tomato paste production in California

As described in the previous section, most of the processing phases for tomato paste production

require energy, and there is potential for energy integration between some of these phases. A

number of studies have been developed on energy recovery around specific facilities in the main

tomato paste producing countries (e.g. USA: California).

Approximately 35% of global tomato processing takes place in California (Trueblood et al., 2013;

Morning Star Company, 2014). According to Trueblood et al., (2013) processing tomatoes is

extremely energy intensive with approximately 6% of the total costs of the tomato processing

operation in Californian plants spent on energy, and great potential to reduce consumption (and

costs) of energy and fresh water via efficiency and demand management measures, especially if

energy and water are considered together.

Studies such as that of Rumsey et al., 1984 investigated the efficiency of the evaporation process in

tomato paste production in relation to technology, i.e. the study looked at daily average

performance data for single, double and triple effect evaporators, and compared their average daily

steam economy against the theoretical average for these evaporators. The study provided baseline

data for future improvements.

Pacific Gas and Electric (PG & E) have studied the potential for energy integration in tomato paste

processing in California by recompressing vapour generated by the evaporation and using this as the

heat source for the evaporation itself, thus reducing consumption of natural gas for the boilers (see

PG & E, 2008). Compared to other evaporation systems such as triple effect evaporators where the

final vapour produced is condensed, mechanical vapour recompression (MVR) compresses the

vapour to higher pressure and recovers the higher energy content of the vapour to use it in the

evaporation process itself, thus resulting in less energy loss.

MVR can reportedly cut down the amount of natural gas used in processing tomatoes into tomato

paste by up to 89%, which suggests that investing in a MVR compressor may be a worthwhile long-

term investment for agricultural process requiring evaporation for concentrate.


18

Amon et al., (2015) have used water and energy usage data to model the potential heat transfer

from evaporator condensate to the tomatoes hot break phase in a commercial scale Californian

plant also. Their study models the recovery of condensate waste heat and its application to the

tomato hot break phase to explore energy and economic savings linked to using less steam,

groundwater pumping, cooling, and wastewater processing. This investigation indicates that heat

recovery and re-using condensate need other processing steps to change so that there is demand for

condensate waste heat, but it can lead to significant reductions in the use of natural gas in boilers

(savings of up to 7.3 GWh) and overall electricity savings (up to $166,000) at the facility, depending

on the heat exchanger design, season and processing conditions.

3.4. Opportunities for tomato paste production in the UK

Around 90% of tomato paste consumed in the UK is imported from the EU (Italy, Spain, Portugal and

Greece), with the remainder mostly coming from China (see LNN Initial Research Note on Tomato

Paste). Some of this tomato paste is re-exported as further-processed food products.

The two fundamental problems identified with potential localised production of tomato paste in

Oxford and /or Cambridge areas are:

1) the inability of UK produced tomato paste to compete with large-scale operations in

regions such as California, and

2) the supply of raw materials near the processing plants, which in the UK would mean

substantial land-use changes to grow tomatoes in green-houses.

These aspects have a negative influence on the cost of tomato paste in the UK and make widespread

re-distributed manufacturing (RDM) of tomato paste a case with little viability in the UK, unless

substantially larger volumes of tomatoes are grown in the UK. This would require changes in land-

use and water and energy supply systems.

Opportunities exist for localising energy systems that can help increase the production of tomatoes

in the UK, for example, by using renewable sources of energy (e.g. energy generation from waste

food and wastewater arisings across the local supply chain, biomass from local sources, solar, hydro,

heat pumps) and through energy integration (e.g. waste heat recovery and re-use in other

processes).

An example of the feasibility of generating energy from waste is presented by the study by Mahony

et al., 2002 for the Environmental Protection Authority (EPA) Ireland. This study in Ireland examined

the potential for renewable energy generation using animal manures and other biodegradable

wastes from the agriculture sector as feedstock. Organic waste arisings originate from agricultural

wastes; urban wastewater sludge; biological sludge from food and other industrial wastewater

treatment plants; organic wastes and wastewaters from the food processing, beverage and other

industries; and from the organic waste within municipal solid waste. The focus of the study was to

minimise surface and groundwater, and soil contamination from animal manure and slurry to meet


19

EU landfill regulation, while exploring also the potential to use phosphorus removed from secondary

effluents of municipal wastewater treatment plants for energy generation.

Tomato juice or processing other products in the same facility may offer further opportunities for

RDM (see LNN Initial Research Note on Tomato Paste).

3.5. Example of tomato nurseries, Worcestershire, and interview with

local tomato grower

A tomato nursery that includes a small facility that makes tomato juice was visited on Monday 26

Oct 2015, and a semi-structured interview was conducted with the owner. The facility includes

three large green-houses growing tomatoes. The footprint of the green-houses is 2 acres which is a

bit less than one hectare (5 acres = 2 Ha). They have no possibility to expand as there is no land

available in the surroundings.

The varieties grown have moved from classic, to loose cherry, to ‘on the vyne’ /truss tomatoes

(which have more waste and less gradable). Thus the waste, which comprising split and misshaped

tomatoes, is now used to make juice. Juice is different to other nearby business like chutney making

in that it does not need onions and cooking, so it does not need massive effort for processing. The

business supplies tomatoes to shops, farm markets and supermarkets, while juice is supplied to pubs

and shops.

Plates 1 and 2 show tomato plants planted approximately 10 months earlier. Seeds are planted in November and into greenhouses in December-January. They are then transplanted in early April to hydroponics, where the roots grow in a solution of water and nutrients with no soil required.

3.5.1. Water

The supply of water is from the main water supplier, but there is also a borehole for spring water

that can and is used in one or two green-houses. The other greenhouse uses mains water.

The system works by having a continuous flow of water with feed that fills the sacks (hydroponics)

by gravity, and the water is re-circulated into a tank also by gravity. The water is tested and water,

feed and temperature are all controlled by a computerised system that adds nutrients when needed.

The owner believes maybe water quality changes towards the summer with less dilution of

chemicals because the plants seem to absorb less iron in the houses irrigated with borehole water,

and their leaves become yellow. Ground water could be stored before the summer when its quality

changes, to be used in the summer, but then there is the need for a water tank that would require

water to be maintained and tested.

Local water is high in calcium and nitrogen. It is hard water and they add nitric acid to acidify water

to pH 6. Borehole water is cheaper to pump than to pay for tap/mains water. The water table is

close to surface (only around 8 m deep).

They still use some water from mains water supply even though they could use all spring water for

which they have no limit and is cheap. Before borehole water was used, the water bill was £20,000

per year. With boreholes, they have to pump the water (spending on energy) but the cost of this is


21

cheaper than using water from mains, but the owner still considers water is cheap compared with

energy.

If you use trickle irrigation, you don’t need to pay an abstraction licence fee and their water supply

has no limits in the area/region where they are.

Water from tomatoes close circuit is used to irrigate cucumbers too. Nutrients fade at the end of the

season (computer-controlled) and they dispose of water freely.

3.5.2. Energy

The green-houses have shades/sun screens that together with water, feed and temperature are

controlled by a computerised system. The nurseries’ owner defined themselves as ‘heat importers’

as the green-houses need heat in winter and vents-on in the summer for ventilation as there is too

much humidity and this can lead to fungi growth.

Each row of tomato plants has a hot water heating pipe that works in a similar way to a normal

central heating where water is heated by a boiler. These pipes (see plate 1) are also used as a rail for

trolleys. The ideal temperature for the greenhouses is 16° C at night and 19° C during the day in all

seasons, from July to the winter months. LED light gives some temperature but heating is still

needed and this is supplied by a coal boiler (see plate 3) and kerosene sometimes. Hardly ever on oil

as this is too expensive. They changed because there was a grant to convert from oil to coal (back in

the 1970s-1980s). This coal is graded (known as shingle), and it is more difficult to find and more

expensive than the coal used in power stations. Their usage is 400 tons of coal in 12 months.


22

Plate 3 shows the current energy source (coal -shingle) used to heat the green-houses

In addition to coal, they also use a paraffin fuel boiler and a chimney and pipes to pump CO2

emissions into the green-houses to help tomatoes ripe more quickly (see plate 4).

Plate 4 CO2 from burning paraffin is pumped into the green-houses to help tomatoes ripening


23

The energy input is significant and the owner sometimes asks himself whether the current way is

cost-effective, and considers whether it would be better to do just one harvest per year in the

summer.

On the other hand, in the hotter months in particular, transpiration is huge especially in the top of

the roof it is very hot and humid, and ventilation is needed which necessitates energy to move vents

and extract air, even with sun/light screens. Transpiration is less in the lower parts where

temperature is cooler.

In terms of efficiencies, the glass of green-houses was replaced 15 years ago with some grants/

funding available and it is recognised that there are better technologies and facilities nowadays. A

similar business has invested around £3 million in continuous LED lighting for green-houses and a

CHP with gas, a fuel that helps reduce the CO2 emissions associated with their crop (gas instead of

coal), and also CO2 emissions can be pumped into the green-house to help tomatoes to ripe more

quickly. New green-house plants have better heating, they are more efficient in terms of heat and

space.

Other synergies or symbiotic processes that could help with energy inputs in this business as well as

in reducing GHG emissions include using heat waste /steamed water from other industries or from

cooling towers for (e.g. obsolete case of Battersea power station in London that provided district

heat for blocks of flats on the opposite side of the River Thames, or the British Coal Nottingham

district heating scheme that provided 3MW of electricity and 80 MW of heat to shops, offices and to

4000 homes (see Drax Group, 2012 and Crook, 1994).

In terms of other sources of energy, the owner acknowledged that it is also possible to use a biomass

/woodchip boiler but this would mean a new heating plant and there are no grants available. There

is some potential to install a Combined Heat and Power (CHP) boiler, and it was reported that 1,000

tons of straw which is equivalent to 2,000 bales of straw as biomass would be needed. Storage

space is an issue for straw-bales, even though this fuel appears the most ready available material

from surrounding areas and thus the most sustainable.

PV panels would need extra land to install as they cannot be installed on the roofs of green-houses

because panels would block the light.

There is potential to use heat from top of green-houses and to capture this heat and store it, for

example in an under-ground water reservoir, to use the heat as needed.

Asked about the potential for coils under the surface of the green-houses (ground sourced heat and

pumps), the owner said this would be low grade heat and blowers may be needed to heat the green-

houses versus the existing system of hot water in rails which is what the farmers are used to. CHPs

and biomass are more familiar to growers, but there is potential to be investigated.

3.5.3. Waste and waste water, and energy from waste

There is reportedly no waste (almost) because split or misshaped tomatoes are used for juice. At

least not enough waste for a CHP probably, nor enough effluent for a biological treatment plant (bio-

digester for effluent treatment before discharging used water into a local watercourse, which


24

requires a consent to discharge from the Environment Agency, and re-using organic recovered

material as biomass).

In terms of waste, the stems of the plants once the season ends are quite long as they are stretched

and turned around the length of the green house (see plates 1 and 2). They could be used as fuel for

a biomass boiler/ CHP, however the rope used to hold the plants in place is very long too and made

of nylon which makes them unsuitable for incineration (see plates 1 and 2). They are shredded and

taken away for landfill instead.

Biodegradable cord is too thick and it gets entangled, it is difficult to manage and it blocks light due

to its volume because it is much thicker than the nylon cord. This is an area where potential

improvements can be made if an alternative rope of biodegradable material equal in thickness to the

nylon rope can be developed. Then the waste from old plants together with the ropes could be used

as biomass. There may also be some potential in using damaged cardboard packaging also.

Plate 5 illustrates the packaging used for transportation of ‘on the vyne’ an cherry tomatoes


25

3.5.4. Juice business model and general aspects

Tomato juice varies depending on the tomato variety used. It is pure squeezed tomato juice. The

acidity is the most important aspect (needs to be below 4.3 and they try to keep it below 4).

Anything above 4.3 they add malic acid (or citric acid) for safety. Cooking temperature and pH are

critical. In Autumn the tomatoes tend to be more acidic.

They nip flower in the vine to make vines shorter, and when tomatoes get ripe, they pick the red

ones at the top for loose tomatoes (too expensive for juice –only split or misshapen tomatoes), and

leave the green ones at the bottom to ripe. If green tomatoes are taken, these can be used for

chutneys.

In terms of energy use for making the juice, this is made in an artisanal way cooking tomatoes in big

pots in a simple home-style kitchen (see plate 6). After bringing the tomatoes to the boil, they have

to be boiling for 20 minutes. After cooking them, filtering the skins out and mashing them, the liquid

is put in glass jars and boiled-pasteurised for 2 hours and then the jars are labelled.

They sell approximately 10,000 bottles/jars per year directly to shops or through whole-sale agents.

90% of the waste tomatoes used to make juice are cherry split tomatoes that would otherwise be

wasted. There is probably more tomato waste among big businesses of tomato growers, and these

may be used as biomass or in bio-digesters for effluent treatment before discharging into local

watercourses.

Plate 6 the small juice-making facility at a Tomato Nurseries


26

4. Energy involved in industrial food processing: the case

of bread

Based on these objectives outlined in the Energy Feasibility Study Profile, existing academic and grey

literature was reviewed and data on energy use for bread, one of the chosen food products to be

examined under the LNN project, were collected from literature, interviews and site visits and are

summarised below.

4.1. Introduction

For the purposes of this project when talking about Bread, this refers to Bread as in unsweetened,

leavened loaves. Typically primary ingredients in the bulk of UK bread are flour from wheat, and

water (60% of total flour in the recipe2) which is therefore the second most important ingredient by

weight added to flour to form dough2. As wheat is the main ingredient for bread, a number of

sources have been examined and data collected which relate to wheat and the energy and green-

house gas (GHG) emissions embedded in growing wheat. These will be detailed in sections below.

The links between water, energy and bread can be considered in the context of the embedded energy in potable water (e.g. energy for pumping, treating and distributing water), and also there are important links between water and the production of wheat for bread (e.g. raw materials cultivation accounts for c. 95% of the water used to produce bread –WRAP, 2013). Water used for wheat growing in the UK is mainly stored in the soils as green water, but the water-footprint of wheat can be more significant in water-stressed areas outside the UK where wheat may be irrigated (e.g. Kansas, Utah, Oregon in the USA).

4.2. Emissions linked to the production of wheat for bread

Wheat is the UK’s most widely grown crop in terms of land area, covering 1.9m ha, or around 30% of

the UK’s arable land. 16.6 million tonnes of wheat were harvested in 2014, with a market value of

£2.4bn3. Of the total harvest, around as much wheat is used for animal feed every year as it is sent

for flour milling. UK wheat yields are amongst the highest in the world, at an average 7.6 tonnes/ ha

compared to a world average of 3 tonnes /ha. This high yield is attributable to the high inputs of

herbicides, fungicides, insecticides, growth regulators, and fertilisers used in the UK2, which is an

important factor to consider in relation to Green-House Gas emissions (GHG).

The use of fertilizers has been seen to be the main cause of GHG emissions in the agricultural stage.

Özilgen and Sorgüven (2011) investigated the production of soybean, sunflower, and olive oils and

found that most of the energy used and CO2 emissions for these products were related to the

agricultural phases as a result of excessive use of fertilizers, and the consumption of diesel, with

soybean having the most CO2 emissions per ton of seeds due to the intensive use of fertilizers to

grow this crop.

2 http://www.bakersassist.nl/rawmaterials

3 See LNN Initial Research Note on BREAD by Julian Cottee, September 2015. DATA from Defra Agriculture in

the UK 2014


27

Karakaya and Özilgen (2011) studied the energy and CO2 emissions involved in the production of

various types of tomato-based products in Turkey including packaging, transportation, and waste

management. This study found that chemical fertilizers and transport are the main contributors to

CO2 emissions. Manfredi and Vignali (2014) also found that fertilizers cause the largest

environmental burdens of growing tomatoes to produce tomato paste, and thus the cultivation

phase was found to have higher environmental impacts than the transportation and processing

phases as a result of the use of fertilizers (eutrophication), pesticides and diesel. Transport to

retailers also contributed to environmental impacts quite significantly.

Thus improvements in terms of environmental impacts from the wheat cultivation phase may

include using organic fertilizers instead of mineral ones and optimizing energy use (e.g. machinery

diesel).

4.3. Bread making and energy requirements

Beyond the agricultural stage, all or most of the mechanised stages in the flour milling process (see

LNN project2) require some energy, with a few specific steps having the most implications in terms of

energy use thus needing further investigation.

Grading and cleaning require minimum energy inputs associated with sieving and separating grains.

The most energy intensive processes in the cleaning stage are linked to aspirators sucking air to

remove light dust.

Conditioning (tempering) is the process whereby water is added to soften the wheat, making it

easier to process. Warm (46°C water for 60-90 minutes) and hot (60°C water or steam) conditioning

have some implications in terms of the embedded energy in potable water plus the energy required

to warm water to high temperatures.

There are also some energy requirements for mechanical processes such as blending, breaking into

middlings, separation/purification of middlings, grinding of middlings into flour by large smooth

metal rollers, and packing into bags for industrial, commercial or household use.

Furthermore, there are important implications in terms of energy involved in most stages of the

baking process, including mixing, proving / fermenting, baking itself (high /very high energy

requirements), and cooling. Both the proving / fermenting and cooling processes may have the

potential for energy-heat recovery and re-use in other processes such as for example the cooking

step).

In relation to the fermenting process of commercial bread produced in the UK, the Chorleywood

Bread Process (CBP) invented in the 1960s is used for most bagged sliced industrial bread on sale.

The more traditional Bulk Fermentation Process (BFP) is used by some smaller commercial bakers

and craft bakers2. While traditional bulk fermentation requires around 3 hours of fermentation

time, the innovation of the CBP was introducing a significant level of mechanical energy, and adding

a mixture of chemicals to the dough, extra water and hard fats so that the fermentation time was

reduced significantly. The whole baking process is reduced from 5 plus hours in the traditional BFP


28

to 3.5 hours in the CBP, and specifically in terms of dough cooking the CBP only requires 17 to 25

minutes for baking, compared to 30 min in the BFP2. Shortening the fermentation and cooking times

is important in terms of energy inputs, although more water and chemicals are needed.

As detailed above most of the national bread in the UK is baked following the CBP method in large

centralised manufacturing facilities that sell to supermarkets and a minority of independent shops,

versus 1-2% of local/artisanal/craft bread produced at the local scale in the UK.

The amount of energy used, energy intensities (energy consumption per unit output), as well as the

emissions involved in bread making are different for centrally produced large scale industrial bread

and for artisanal/craft bread manufactured at the local level. The bread study case is on-going and

defining the system, its boundaries and the various supply chain configurations including for

redistributed manufacturing of bread will be necessary in order to analyse the system’s energy

implications in any detail.

Available literature on energy and potential energy efficiencies in making bread has been reviewed,

and the energy /energy intensity and emissions data below are taken from recent studies on wheat

and industrially manufactured bread for the UK and elsewhere. Furthermore, interviews with local

wheat mills and a local bakery have taken place and the main findings are included below.

4.4. Studies/data available on energy involved in bread making in the UK

4.4.1. Energy used in food manufacturing in the UK

Industry produces approximately 125 million tonnes of CO2 (MtCO2) per year which is equivalent to

25% of the UK’s total emissions4. According to the Carbon Trust (2010), savings of 4-6 MtCO2 (up to

4% of current emissions) could be realistically achieved in industry with appropriate interventions.

Within this context, Tassou, Kolokotroni, Gowreesunker et al., (2014) offer an extensive literature

review of the UK’s food manufacturing sector reporting that this accounts for 15% (60 TWh) of the

total food-chain energy use, producing 13 Mt of CO2 equivalent emissions (Mt CO2e).

Based on their review of existing studies, Tassou, Kolokotroni, Gowreesunker et al., (2014) offer a

breakdown of the type of fuel used in food manufacturing as 61% natural gas, 31% electricity, 6%

petroleum, with fuel oil and coal accounting for the rest. They also report that the majority

(approximately 68%) of the energy is used by fuel-fired boilers and heating systems for process and

space heating, 16% of the energy used is electrical energy used by electric motors, 8% is used by

electric heating, 6% by refrigeration equipment and the rest by air compressors.

This paper also reports that the energy consumption figures indicate that 80% of the carbon

emissions in food manufacturing are linked to only a few products including bread and fresh

pastries, beer and alcoholic beverages, and the production of cheese, dairy, meat and poultry

4 http://www.carbontrust.com/client-services/technology/innovation/industrial-energy-efficiency-accelerator

http://www.carbontrust.com/client-services/technology/innovation/industrial-energy-efficiency-accelerator


29

products. They also highlight the vast amounts of food waste that is mainly landfilled. The authors

point out the need to use resources more efficiently to minimise waste, to the potential for

producing by-products and for energy recovering from waste (via efficient incineration, gasification,

pyrolysis or anaerobic digestion), and to the need to improve technologies such as processing

equipment, refrigeration, boilers, ovens, pumps, space heating and lighting. They also indicate that

energy can be saved at the processing plant level by optimising and integrating processes and

systems.

4.4.2. Energy and green-house gas (GHG) emissions of growing wheat in the UK

In the UK, the Department for Environment Food and Rural Affairs (DEFRA) commissioned a study by

Cranfield University that using Life Cycle Assessment (LCA) investigated the resource use and

environmental impacts of 10 common agricultural and horticultural commodities including wheat

(see Williams et al., 2006). The study found that producing bread wheat (only 0.7% of which is

organic) consumes 2.5 gigajoules (GJ5) of primary energy per tonne of wheat (1.7 GJ per tonne of

organic wheat), and produces 0.80 t CO2 (projected global warming potential over 100 years) per

tonne of wheat.

Unlike in industry where CO2 from fuel use contributes to the majority of the GHG emissions, in

agriculture GHG emissions are mainly linked to the Nitrogen cycle, with N2O and N from field crops

as the gases with most global warming potential –e.g. 80% in wheat production, followed by

methane from livestock production.

In terms of energy usage, the DEFRA study provides the following breakdown.

Table 1 Energy for producing bread wheat non- organically and organically (per t produced)

Energy used Non-organic Organic

Primary Energy used, MJ per tonne produced 2,460 1,740

Primary Energy Usage Proportions Non-organic Organic

Field work: Cultivation 19% 60%

Field work: Spraying 3% 0%

Field work: Fertiliser Application 3% 3%

Field work: Harvesting 8% 21%

Crop storage & drying or cooling 5% 8%

Pesticide manufacture 8% 0%

Fertiliser manufacture 53% 9%

According to Williams et al., (2006) approximately 27% less energy is used in growing organic wheat

compared with non-organic wheat because of the use of synthetic N for non-organic crops.

5 1GJ (Gigajoule)=277.7 kWh, thus 2.5 GJ is the same as 694 kWh of energy used per tonne of bread wheat.


30

However, the reduction in energy use in organic bread wheat systems is offset by lower yields,

higher inputs into fieldwork, and up to 200% more land needed. The study points out that energy

use can be reduced by 9% by using a new variety of wheat that increases yield by 20%.

Other studies on wheat and associated emissions include Galli et al., (2015) that assesses the

performance of both global and local wheat to bread chains as various scenarios, and Charles et al.,

(2006) that undertakes a Life Cycle Assessment (LCA) of the wheat production system for bread-

making to ascertain under which fertilization intensities there is sufficient yield increase (crop

productivity) to justify additional emissions. This study analysed the intensity per hectare and the

grain production and quality of the product, and indicates that low intensity crops are

environmentally favourable but can reduce productivity and shift pollution elsewhere. The study

also states that as a whole, the efficiency of using nitrogen fertilizers is high in increasing the

productivity of wheat.

4.4.3. Energy and green-house gas (GHG) emissions associated with the industrial

bakery sector in the UK

The Carbon Trust in 2010 undertook a project looking at the bakery sector in the UK specifically.

Findings from this study indicate that each year, the UK industrial bakery sector produces

approximately 2.5 million tonnes (Mt) of baked goods, mainly bread, across 89 sites, and to do so,

requires energy consumption of some 2,000 gigawatt hours (GWh), which equates to emissions of

approximately 570,000 tonnes of CO2 (tCO2) per year, broken down as per Table 2.

Based on there being 89 industrial bakery sites, the average emissions per site are 6,400 tCO2 per

year.

Table 2 Annual bakery sector energy consumption and carbon emissions

Energy type Energy use (GWh) CO2 emissions (tonnes)

Electricity (delivered) 560 300,000

Natural gas 1,400 260,000

Fuel oil and Liquid Propane Gas 40 10,000

Totals 2,000 570,000

According to this study by the Carbon Trust between 35-40 % of the CO2 emissions for a total site are

associated with the baking process, approximately 5% corresponds with final proofing, and between

5-10% corresponds with the cooling process. Emissions relate to electricity for motors and drivers,

gas for heating, and steam or water for product quality, humidity control and cooling.

The overall maximum carbon saving potential for the sector through good practice and future

innovation is estimated to be 26.5% or 151,000tCO2 per year. The good practice element of this,

through well-documented efficiency measures reportedly can deliver around 10% carbon savings,


31

with innovation expected to help saving the additional 16.5% identified (94,000tCO2 per annum).

However, the level of carbon savings that are actually achieved will depend on how many measures

the sector implements.

4.4.4. Energy intensities of bread in the UK

The Carbon Trust (2010) study analysed actual annual energy data for 13 bakeries, and the following

energy intensities were calculated based on the amount of delivered energy a site uses each year

and its annual production (i.e. energy intensity=delivered energy per tonne of product produced):

Fossil fuels (predominately gas) 551 kWh per tonne of product

Electricity 218 kWh per tonne of product

Other energy intensities for bread at different scales (including home baking) have been reported in

the UK. A study by Beech (1980 -published online in 2006) studied the energy used in production of

standard, white, sliced bread in three UK bakeries. The full production system as well as only the

production chain covering all stages (from flour arrival at the bakery to arrival of bread at the retail

outlet) were examined and the following intensities are reported:

Primary energy use from all sources in the production chain averages c. 7 (6.99) MJ6 /kg of bread.

Primary energy consumption in the complete production system for standard bread, including wheat growing, flour milling, baking and retailing is c. 15 (14.8) MJ /kg of bread.

Primary energy used in home baking was dependent on the degree of loading of the oven and varies from c. 4 to 16 (4.24-16.05) MJ /kg of bread baked in a gas oven to c. 11 to 55 (10.84-54.76) MJ /kg of bread baked in an electric oven.

According to Beech (1980 & 2006) research suggests that compared with other foods such as

mashed potato, roast beef and reheated canned corn, bread is the most energy efficient staple food

product of an industrialised food production system by a factor of at least five. The study also

indicates that baking at home in an electric oven tends to be the most inefficient way of making

bread.

Le-bail et al., (2010) report on a European (FP6) project known as ‘‘EU-FRESHBAKE” about the energy

demand in conventional bread baking versus in the processing of frozen part-baked breads. Bread

baking is one of the most energy demanding processes (c. 4 megajoules (MJ)/kg), compared with

other processes such as canning (see Figure 3). For partial baking, bread has to be baked twice, and

it may also be frozen after part-baking, which will increase the total energy demand. Results

obtained with equipment used by craft bakeries are presented. Conventional and frozen part-baked

processes are compared and it was observed that 15–20% of the total energy is used for heating up

the dough and 10–20% for crust drying. Pre-heating of the oven represents another significant

6 1 Watt= 1 Joule per second (J/sec), 1 kilowatt hour (kWh)= 3.6 megajoules (MJ), and 1 MJ =0.28 kWh


32

energy demand. The energy demand for freezing is comparable to that for baking. Part-baked frozen

technology demands about 2.2 times as much energy as conventional bread making process.

Figure 3 Comparison of the energy demand for selected food processes. Source: Le-Bail et al., 2010

after Dinçer, 1997 and Fellows, 1996.

Barling et al., (2011) looks at ethical concerns in the UK wheat and bread chain, and provides data on the areas of UK wheat, prices and uses of wheat in the UK. As shown in the data below, approximately 60% of the wheat grown in the UK is destined for animal feed. Table 3 UK wheat supply and use, 2005. Source: Barling et al., (2011)

Production

Area (000 ha) 1,867

Yield (tonnes/ha) 8

Volume of harvested production (000 tonnes) 14,735

Prices

Milling (£/tonne) 83

Feed (£/tonne) 78

Imports/exports (000 tonnes)

Imports from the EU 662

Imports from the rest of the world 500

Exports to the EU 2,161

Exports to the rest of the world 11

Total domestic uses (000 tonnes) 13,559

Of which: Flour milling 5,578

Animal feed 6,890

Seed 254

Other uses and waste 837

% home-grown wheat in milling grist 82

Based on the studies available, the energy requirements of producing wheat in an intensive way (i.e.

using nitrogen as fertilizer) constitute the majority of the energy embedded in bread. If considering


33

the bread making process alone, the baking stage consumes the most energy in the production of

bread, but the energy intensity of bread making varies substantially based on scale (i.e. industrial

baking is more efficient than home baking) and the type of equipment used (e.g. gas ovens are more

efficient than electric ovens at home). Therefore, energy intensities reported range widely from 4 MJ

/kg to 55 MJ /kg of bread produced.

This has implications for a potential move towards more re-distributed / localised bread

manufacturing, thus efficiencies in the baking and other stages of bread making will have to be

implemented to make localised bread making viable in comparison with large-scale centralised

industrial bread making.

Table 4 offers a summary of energy intensities for wheat production and bread making as reported

in various studies, and the following section summarises findings on energy efficiencies and

potential improvements from the literature available.


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Table 4 Summary table of primary energy requirements / energy intensities for wheat and bread production

Primary energy used to grow bread wheat

Primary energy used in UK bakeries -complete production system for standard bread (including wheat growing, flour milling, baking & retailing)

Primary energy used in UK bakeries -production system for standard bread (flour arrival at bakery to bread arriving to retail outlet)

Primary energy used in home baking (gas oven)

Primary energy used in home baking (electric oven)

Primary energy used in bread baking (conventional bread baking)

Primary energy used in part-baked/ frozen bread baking

Source

2.5 gigajoules (GJ7)

(or 2,460 megajoules: MJ) per tonne of wheat 1.7 GJ (or 1,740 MJ) per tonne of organic wheat

Williams et al., (2006)

15 (14.8) MJ /kg of bread

7 (6.99) MJ /kg of

bread

4 to 16 (4.24-16.05) MJ /kg of bread

11 to 55 (10.84-54.76) MJ /kg of bread

Beech (1980 –published on-line in 2006)

4 MJ/kg of bread Le-bail et al., (2010)

8.8 MJ/kg of bread part-baked/ frozen bread demands about 2.2 times as much energy as conventionally made bread

Derived from Le-bail et al., (2010)

7 1GJ (Gigajoule)=277.7 kWh, thus 2.5 GJ is the same as 694 kWh of energy used per tonne of bread wheat.

Energy Feasibility Project Report

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4.4.5. Emissions associated with bread in the UK

When looking at the emissions specifically associated with bread in the UK, according to WRAP

(2013) bread baking (at plant, in-store or at home) is reported to be responsible for 20% of the GHG

emissions of bread, while user behaviour (bread freezing and toasting) and appliance use contribute

25% of the total GHG emissions, and fertiliser use in wheat growing accounts for 25% of the total

GHG emissions.

On the water footprint of bread, wheat cultivation accounts for over 95% of lifecycle water use of

bread in the UK. On bread wasted in the home, WRAP reports that about 660,000 tonnes of bread

(worth £640 million) is wasted in UK homes every year.

4.4.6. Energy efficiencies in the bakery sector

In terms of energy efficiency studies in the bakery sector, the Carbon Trust (2010) study on industrial

bread making in the UK points out to energy savings derived from well-tested efficiencies and

innovative opportunities for carbon emissions reduction across four areas: improving oven

combustion efficiency, reducing thermal mass of baking tins, improving control of oven and cooler

electrical equipment, and recovering oven heat.

However, in line with other studies reported in Table 3, the Carbon Trust study (2010) also shows

that there is significant variation in the specific energy consumption depending on differences in the

baking operations (e.g. product formulation and type/s of product, production volumes, operating

hours), plant technology (e.g. degree of automation, efficiency controls on process and space

heating systems), and site location which influences heating demands.

Potential areas for improving energy performance in bread making plants are reportedly driven by

compliance with regulations, cost control and corporate responsibility, and include actions such as:

turn-off and energy awareness campaigns for conveyors

monitoring and targeting programmes

shutdown procedures for provers, ovens, coolers

improved insulation of major process plant such as ovens and provers

improved insulation of steam and chilled water distribution systems

compressed air management practices and more efficient/less leakage in air compressor plant, including:

o variable speed drives (VSDs) on bakery ventilation systems

o reducing the amount of air entering despatch areas – by improving seals and air curtains

high-efficiency lighting applications and occupancy control of lights in lower use areas such as offices, meeting rooms, stores and plant rooms

space heating control improvements – office wet systems temperature compensation and boiler optimisation; process area convector heater advanced controls


36

Research has recently been developed in some of these areas, for example, Patton (2013) focused

his research in investigating ways of improving the efficiency of industrial processes associated with

commercial bread-making. Patton looked at the energy used in bread manufacturing in order to

provide solutions to improve efficiency in commercial bakeries as well as to reduce their

environmental impact. Paton identified that between 40 and 49 % of heat is wasted in industrial

ovens, and that the proofing (or proving) process, where dough is exposed to specific amounts of

heat and humidity to activate yeast, is responsible for 5 % of carbon emissions in bakeries. He

identified that standard practices use large volumes of air-flows and provers are over-engineered

affecting energy costs, even though the need for such air-flows is not scientifically justified. Using

simulations of various air changes in experiments, this research indicates that efficiencies can be

made in the ‘proofing stage’ and that it is possible to reduce airflow by 33 % and electricity demand

by over 70%.

The Carbon Trust (2015a) is also working on improving the efficiency of bakery ovens, and research

indicates that up to 42% of energy savings are possible by optimising flue gas. The Carbon Trust

(2015b) reported that industry trials demonstrate that improved ventilation in ovens through the

use of variable speed drives and sensors can lead to significant energy efficiency improvements

when baking bread.

4.4.7. Summary of the energy implications of making bread in the UK

The following main findings have been summarised from the studies on energy consumption for part

or the whole of the life cycle of the production of standard bread in the UK detailed in the sections

above. In the work by Beech published in 1980, he estimated the primary energy consumption for

growing bread wheat to c. 4 MJ/kg bread (out of the total consumption of c. 15 MJ/kg bread for

wheat production, milling, baking and keeping in shops), which is significantly higher than 2.5 MJ/kg

wheat, an estimate for standard bread wheat growth from a more recent study by Williams et al.,

(2006). The latter work also presented an estimate of 1.7 MJ/kg organic wheat, the reduction

compared to the standard wheat is mainly because of the avoided use of synthetic nitrogen

fertilizers. However, the reduction in energy use in organic bread wheat systems is offset by lower

yields, higher inputs into fieldwork, and up to 200% more land needed.

Among the manufacturing steps, the baking process appears to be most energy-intensive. Beech

(1980) estimated the primary energy consumption of standard industrial making to c. 7 MJ/kg bread.

In comparison, the Carbon Trust (2010) study analysed actual annual energy data for 13 bakeries,

and the following energy intensities were calculated based on the amount of delivered energy a site

uses each year and its annual production, with estimates of 551 kWh of fossil fuels (predominately

gas) and 218 kWh of electricity, per tonne of product. Assuming a 35% conversion rate from primary

energy to electricity, this is approximately 4MJ/kg bread of primary energy, which is very close to the

estimate from a European study by Le-bail et al., in 2010.

It appears that the more recent studies have shown a greater energy efficiency across the life cycle

of bread production, which may be attributed to improvement in technology and practice. More

interestingly for re-distributed manufacturing and in relative terms, Beech (1980) concluded that

compared to industrial baking, energy consumption of home baking could be lower if sufficient


37

loading (e.g. 2-3 loafs of 670g each per batch) is adopted and gas is used as the fuel; the efficiency

can drop significantly with lower loading levels and in any case with electricity-power ovens. Le-bail

et al., (2010) on the other hand, compared the energy demand in conventional bread baking with

that in the processing of frozen part-baked breads and concluded that the part-baked process

demands about 2.2 times as much energy as conventional bread making process.

Closely related to energy consumption is greenhouse gas (GHG) emissions. According to Williams et

al., (2006), 0.80 t CO2 equivalent is produced per tonne of wheat, 80% of which arises from the use

of fertilisers. For the bakery operations, the Carbon Trust study (2010) showed 0.23 t CO2 equivalent

per tonne of baked product (primarily breads) when averaged across 89 industrial bakery sites in the

UK, mounting to 0.57 million tonnes of CO2 equivalent per year and responsible for approximately

0.45% of the UK’s industrial emissions. The overall maximum carbon saving potential for the sector

through good practice and future innovation is estimated to be 26.5%. In a separate study by WRAP

(2013), bread baking (at plant, in-store or at home) is reported to be responsible for 20% of the GHG

emissions of bread, while user behaviour (bread freezing and toasting) and appliance use contribute

25% of the total GHG emissions, and fertiliser use in wheat growing accounts for 25% of the total

GHG emissions. While a detailed study is needed to draw definite conclusions, it can be suggested

that if changes occur to the locations and scales of different activities in the bread system, and in

user behaviour, the picture of GHG emissions is most likely to change.

4.4.8. Wastes and by-products from the bread supply chain and potential for energy

generation

Across the whole UK food system, bread is one of the products with the highest wastage rates.

According to estimates by Tesco, 34% of bread that is produced is never eaten. The figure is higher

for sliced, white bread, of which 44% is never eaten.8

Waste from milling (germ and bran) often used for animal feed and also as fertilizer, so milling waste

is considered to be minimal/negligible.

Waste from baking up to 16% of bread (smaller percentage in smaller-scale bakeries) produced is

wasted at manufacturing stage due to overproduction, misshapen or poor quality loaves, stoppages

and burning caused by malfunctions and human errors3.

Waste in the retail stage is reported to be between 1-4% of bread produced or 4.3% of bread sales

including bread ‘reduced to clear’ (one of the biggest single areas of food waste9 ).

Waste at consumer level. By weight, bread is the number one household food waste product. In

2012 households disposed of 460,000 tonnes of standard bread and 49,000 tonnes of speciality

bread, mainly because it was not used in time or they were ends and crusts. It is estimated that 28%

of bread purchased in 2012 was wasted.10 This wasted bread (other study food products and

possibly other by-products not used for animal feed) supposedly is composted. Explore potential to

8 Tesco (2014) Food waste hotspots

http://www.tescoplc.com/assets/files/cms/Resources/Food_waste/T_S_Hotspots_190514v3.pdf 9 Tesco (2015) Corporate responsibility 2014/15 half-year update http://library.the-

group.net/tesco/client_upload/file/Half_year_report_2014_15.pdf 10

WRAP (2012) Household food and drink waste in the United Kingdom 2012

http://www.tescoplc.com/assets/files/cms/Resources/Food_waste/T_S_Hotspots_190514v3.pdf

http://library.the-group.net/tesco/client_upload/file/Half_year_report_2014_15.pdf

http://library.the-group.net/tesco/client_upload/file/Half_year_report_2014_15.pdf


38

use locally for energy generation -EfW potential. Also note that ‘potable water’ and its embedded

energy is also wasted in the process. Perhaps buying locally made bread every day could help

reducing bread waste, thus avoiding wasted energy and water too.

Consider there is also the drive for supermarkets to reduce waste and donate food close to expiry

date to food banks (e.g. new EU regulation coming into place), thus it is possible that the situation

around bread waste will change in the near future. This could be the basis for different policy

scenarios to model.

4.5. Interviews with local mills and bakeries

Semi-structure interviews were conducted with two local mills in the Oxfordshire area, and with a

local bakery and local scale bakery facility also located in Oxfordshire in October and November of

2015. A draft of the questions to be asked at the semi-structured interviews was prepared and can

be seen in Appendix A. Main findings from the interviews relevant to the energy study are

summarised below.

4.5.1. A Mill, Oxfordshire

This Mill was visited on 16 Oct 2015, and the Managing Director and Production Manager were

interviewed. Their customer-base is national, they supply soft biscuit flour for 3 big companies in

Dublin and for shops and some supermarkets like Aldi. They have much bigger competitors for

example Finelady bakery in Banbury or Heygates, which produces 70 tons of flour per hour

compared to Matthews mill which produces 3-4 tons per hour. They have increased production to

500 tons per week by increasing their power, but even with this they have limitations to do with size

of their factory and location which means they cannot expand. They are next to the railway line

which their ancestors viewed as key for their business (i.e. to transport the flour out of the premises

-most mills were located near ports and river-ports). They have moved towards an approach of

diversification of products instead.

4.5.1.1. Energy

The mill’s energy has always been provided by a gas turbine, and also have electricity, and it is run

24 hours 7 days a week unless there are issues of staffing.

They looked at the possibility for installing solar panels on the available roof but this would require

an investment of £40,000 and approximately 7 years pay-back time with subsidies, which is still

expensive and would only provide approximately 4% of their energy needs as they do not have

enough roof space. The mill (like most mills) are vertical structures with 3 floors to use one conveyor

on the vertical.

They would install solar panels if the upfront cost was not so much. Efficiency of the carbon tax and

carbon credits is questionable, but localised/decentralised energy provision would beneficial for

Corporate Social Responsibility (CSR)/emissions/environmental reports and for public relations and

trust.


39

They pay £22,000 per month in electricity which is associated with the milling machines which have

all moving elements to mill grain into flour, and with dust collectors and fans. Air conveying is an

energy intensive activity.

Three is no energy involved in heating anything. Conditioning uses only cold water so water does

not have to be heated.

In terms of efficiencies, they are operating a similar system to what they had 90 years ago and in the

same building. They are not wasteful, but there are more efficient motors (e.g. German) nowadays

and larger mills can be more efficient too.

Production manager did not perceive that there is much that can be improved: ‘the milling industry

has not changed massively in the past 100 years’. There is only a small efficiency gap between top-

end and slightly less good equipment – cheaper Chinese motors are 96% efficient vs German motors

which are 99% efficient.

They could not operate better/larger machines given space constraints and power available. They

have a power correction factor in the three-phase system11, and they are balancing limitations in

terms of power by putting a new substation to secure supply, but still this isn’t enough power. This

has to be seen versus the potential from renewables (e.g. solar energy potential as described above).

The only real way to improve efficiency was seen to be a fresh start in a new mill. Interviewees

reported that Whitworths have opened a new mill with latest technology, only a one-storey

operation rather than spread over several floors like this mill (possible to use up to 5 Megawatts in

large size factories –order of magnitude, which is similar to modern high-power diesel-electric

locomotives typically have a peak power of 3–5 MW, which has to be seen versus renewables).

4.5.1.2. Water

Thames Water is the water supplier and they use this mains water without needing to check water

quality for conditioning which requires only a small amount of water. Maximum 4-5 baths-full per

day (200l/hour maximum). Thus, they reported hardly any expense on the water bill which was seen

as very small bill compared to the energy bill. Water is not heated for conditioning (cold

conditioning).

4.5.1.3. Waste and energy/circular economy

There is no waste from wholemeal flour, and what does not go into wholemeal flour, the flakes or

bran is sold locally to farms as animal feed. When the feed market was poor due to less demand for

11

Converters with power factor correction (PFC) capability are used in distributed power systems and are implemented using two-stages consisting of a PFC stage followed by a DC/DC converter. The purpose of the front-end converter is to regulate the DC output voltage, guarantee current sharing, and charge a bank of batteries to provide backup energy when the power grid breaks down. One of the main concerns of the power supply industry is to obtain a front-end converter with a low-cost PFC stage, while still complying with required standards, especially for high-power three-phase applications. Barbosa, P. M. (2002) ‘Three-Phase Power Factor Correction Circuits for Low-Cost Distributed Power Systems’, PhD thesis, Virginia Polytechnic Institute and State University.


40

feed during the BSE (mad cow disease) crisis, bran was burned at Didcot power station along with

saw-dust. It was a bit of a biomass experiment, but the price of wheat and bran for animal feed is

led globally, and so when the value of bran for feed rose again, they sold once more for feed.

4.5.2. B Mill, Oxfordshire

This mill was visited on 19 October 2015, and a semi-structured interview took place with the owner.

Their customers are at national scale, but this mill mostly supply small bakeries, some of which are

local to them, farm shops and private local customers too.

The mill’s running cost is approximately £180/ton which compares to £40 a ton for larger mills.

Labour is one of the highest running costs – this rolling milling plant is not an efficient mill. For this

mill, 2 men on a shift produce 2 tons/hour (no computerised milling). At a big plant a computer

makes 60 tons/hour.

4.5.2.1. Energy

In terms of carbon savings and incentives/discounts, they prefer to take the fine than consider

efficiencies which would be more expensive. They pay 10% which is approximately £8,400 which

still means savings per year compared to having to change machines/other efficiencies. There is too

much bureaucracy to save carbon.

Energy is mains electricity. The electricity bill is £7,000 per month. They consume approximately

80,000 KW/month. Hydro-electricity (in the best of times) is a very small proportion of this.

The use electricity from the grid, although they have a screw-hydraulic wheel in Oxford on the site of

the original mill now transformed into flats.

The energy generated is sold to the grid, but there has been no rain and flow levels are low, so in the

last three months they have not used and have not been able to sell any hydro-electricity generated

on the site.

This wheel produces approximately 30KW/hour which is enough to provide electricity for 5,000

houses. In 3 years, this screw has produced 0.5 million KW, so in 36 months this equates to 13,888

KW/month. This is 17.3% of the energy needs of this mill. However it should be noted that no

electricity has been produced in July-August and September 2015 due to low flows.

In the old times, this would have been sufficient to produce 1 ton of flour per hour because less

energy was required before as there were no air conveyors (no energy to blow flour around was

needed).

The current mill run on this mill at the current site in a village near Oxford does not work and the

flow is and was too little even some 80 years or more ago, so no other cheaper available source of

energy than mains electricity.


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4.5.2.2. Efficiency

Large mills are more efficient, for example it could be better to use heat and gas combined. New

mills for example, have 10 floors instead of 3 floors and new machines. They are too small and

cannot afford or cannot accommodate efficiencies in the building. They only produce 6-7 lorry loads

per week compared to 2 lorries per hour in the large factories.

Under Climate Change Levy, the mill has been asked to increase efficiency by 8%, but there is no way

for them to do this by investing in new more efficient machines. In order to increase efficiency they

would have to start again with new machinery and produce on a much larger scale – a new mill

would cost £3-4m, and would need new electricity system, new premises/location, new expensive

rent etc.

They opt for paying the Climate Change levy instead which means 10% higher cost, but 80% can be

returned if you buy carbon credits and do your paperwork correctly.

4.5.2.3. Waste

Everything not made into flour is sieved and sent back to farms for pigs feed, which is paid at £1 per

ton, although Paul knows that you could get more, like £3-4 per ton if this was going to waste (for

composting or biomass?).

Paper-bags which are the main packaging materials go to landfill or incinerator– these can’t be

recycled because they are considered ‘contaminated’ with food.

4.5.2.4. Water

• 1 % water added to wheat for cold conditioning.

• Very minor part of the milling process thus water is a minor problem, they have a small bill.

• There is no effluent

• They use mains water supplied by Thames Water, and this is already tested as part of SALSA

certification.

4.5.3. Village bakery and local bakery facility, Oxfordshire

The village shop and workshop was visited on Wednesday 28 October 2015, and the owner was

interviewed. The business opened in 1972 (by the current owner’s father). They are wholesale

bread, cakes and sandwich suppliers (see plates 7 and 8). They produce locally and use local

products. They also sell in local markets and have another shop in a different village. The main

production facility and store is also nearby.


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Plate 7 the Bakery, Oxfordshire

Plate 8 Detail of products made and sold at the Bakery, Oxfordshire

From the point of RDM, they meet all ‘local’ scales (they produce and sell locally using local produce/

grown locally). They use local flower supplied by a local mill -who are small local producers. They

trust this mill’s flour to sort the flour’s origin to make it as local as possible. They sell the flour in the


43

shop and also use it for baking bread, cakes etc. When the owner started baking 95% of the flour

was Canadian and 5% was English, now it is very different as flours can get gluten added. Their

gluten-free bread mix comes from Germany.

They currently use 4.5-5 tons of flour/week in all premises. The amount of flour used correlates to

approximately 1.6 tons of bread per ton of flour.

Their business in approximately 70% wholesale (they travel in Oxfordshire and Buckinghamshire in a

c. 50 miles radius). They supply competitively to cafes, shops, hospitals and schools (most are price

driven, but some are not even though they are not private but funded by Oxfordshire).

4.5.3.1. Energy

In the village shop they have installed solar panels which are operational since April 2015, but there

is no potential for expansion on south facing roof. In the production site there is no potential for

solar energy for the business as the landlord has already developed it as a solar field.

In the premises they use all the solar energy they produce. Since April this amounts roughly to 3,300

Kilowatts (KW) split as: 641 KW in May, 732 KW in June, 614 KW in July, 457 KW in August (less due

to cloud cover, no higher temperature), and 446 KW in September (plus October’s generated energy

–the month was incomplete at the time of the interview).

The calculation is that the solar panels payback time will be 6 years, but the owner thinks this is

conservative and he’ll pay them sooner. They have feeding tariff (if they sell energy to the grid) but

they use it all and need more. They had no loans or subsidies for installation.

The business’ energy provider is British Gas, and in this village shop and bakery workshop the energy

bill is approximately 5,000 KW per month (mains electric). This means that the bakery produces

approximately 11% of their energy needs via the newly installed solar panels.

4.5.3.2. Energy efficiencies

There is room to have more efficient ovens and machines; these are quite small so less energy-

efficient in comparison to large production centres. Ovens, mixers etc. are from 1988 or 1989 made

in Manchester. They got new ovens in the new production facility which were supposed to be more

energy efficient but are not in reality, because it takes too long for them to heat. His energy bill is

still too large, and he reported that he partly-regrets not going for some wood pellet ovens that he

had seen, but that were too new at the time and he was worried about the supply of

pellets/woodchips.

The new machines for the other bakery / production plant were all made in Italy and are all electric.

In addition to the electricity bill, he is concerned with vans/fleet fuel, and will consider electric fleet

when/if he needs to replace vehicles. Vehicle efficiency is high in the agenda, for economic and

moral reasons.

Waste was not mentioned.


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4.5.3.3. Water

They installed a water meter as the company, which is Thames Water, insisted, but water

consumption is not a concern for the business. The electricity bill and vehicle fuel are much higher

in the list of worries.

Water in the winter and if very cold has to be heated by kettle sometimes to add to the mix, and in

the summer it has to be cold or with ice, but no significant energy input required for either.

5 Summary of findings relevant to the Energy Feasibility

Study from one-to-one interviews

A number of important findings from one-to-one interviews have been summarised below.

However it should be noted in the context of energy and possible configurations that even among

independent local businesses such as mills, there are uncertainties around how much of the locally

manufactured product (e.g. flour produced by a local mill such as A mill near Oxford) ends being

consumed locally for bread and cakes baked in and around Oxford, and how much of it goes to other

places.

All businesses interviewed so far have looked at and continue to consider energy efficiencies and some have installed renewable energy solutions such as solar panels and micro-hydroelectricity schemes. However the energy demand of all businesses interviewed is greater than the energy supply they believe they can produce themselves, which ranges from 4% (A mill feasibility study on solar potential) to 11% actual solar power generated at the village bakery and workshop facility, and 17% hydroelectricity generated at B mill.

All businesses interviewed have looked at available options and have incorporated ‘easy wins’ in terms of energy and water efficiencies as there is a clear understanding by the owners of the links with economic savings.

However, there are physical limitations to possible efficiencies too (old buildings and machines) unless relocating the manufacturing plant and investing significant capital. Business decision makers feel it is preferable (in some instances) to pay the Carbon levy than to invest in making the manufacturing process more efficient.

Some local food manufacturers have the potential to switch technology (e.g. from coal to biomass, or even to ground-source low grade heat in the case of tomato green-houses). However there are financial and physical barriers to installing or retrofitting these technologies (e.g. 2,000 local straw-bales to use as biomass to heat green-houses would require large storage space that is not available; or the roof of the bakery facility already has solar panels owned by the landowner).

Energy-wise, all businesses interviewed pointed out that newer and larger operations have more room for efficiencies and are more competitive due to economies of scale (e.g. tomato paste factories, or large mills manufacturing 24 hours 7 days a week). Space to grow the business and to change technology is the main/one of the main drivers for change.


45

Local businesses investing in green technologies and looking positive about the future are family businesses where young generations of family members are involved in the business.

‘Redistributed manufacturing’ means different things for different people, thus we could talk of

grades of decentralisation/redistribution. ‘Local scale’ also means different things for different

people, e.g. a medium or even small-size local mill can supply at national (or even international)

scale across the whole UK, and use international organic wheat for locally crafted bread (i.e.

from countries as far away as Canada or Australia) depending on the year, the quality of the

yield and prices on global market.

5.1. Areas for further investigation according to interviews and site visits

5.1.1. Tomato paste case study

Potential to re-use and/or store heat from the top of the roof peach of greenhouses (heat

capture, storage for example in under-ground water reservoirs).

Potential for ground-sourced heat (coils) under the surface of the green-houses

Other synergies or symbiotic processes including using heat from steam/water from cooling

towers for local greenhouses.

Relocating greenhouses near industries with excess energy losses e.g. bakery.

Biodegradable cord to hold tomato plants is too thick and it gets entangled, it is difficult to

manage and it blocks light due to its volume because it is much thicker than the nylon cord.

This is an area where potential improvements can be made if an alternative rope of

biodegradable material equal in thickness to the nylon rope can be developed. This would

mean that old plants together with the ropes could be used as biomass.

5.1.2. Bread case study: mills

• Potential for ground-sourced pumps

• Other synergies or symbiotic processes including using heat from steam/water from cooling

towers in power stations to store energy in water reservoirs/move turbines etc.

• Potential for using other wasted / energy losses energy from other industries e.g. bakeries

for milling, which may mean relocating mills near those industries

• Potential for CHPs/biomass? EfW? Solar –if cheaper- hydro, other sources of renewable

energy? Including potential to use packaging material (paper-bags) and waste bran as

biomass for a CHP instead of landfill or incineration.

5.1.3. Bread case study: bakery shop and local bakery facility

The role of family-run small and medium businesses as key drivers of RDM (e.g. in the mills,

bakeries, green-house horticulture and brewery businesses). Thus, replicating the family

business model in RDM may be useful.

There is potential to use heat losses from another industry (e.g. power station) to make

bread, which may mean geographical relocation of manufacturing facilities. There is also

potential to store heat from ovens (capture/ storage for example in under-ground water


46

reservoirs) and to re-use heat in other processes/industries (e.g. locating a bakery next to a

green-house for symbiotic processes).

6. Stakeholder engagement

In addition to the one to one interviews and site visits presented in the previous section, a variety of

national and local stakeholders were consulted through workshops held in London and Oxford.

Feedback from stakeholders relevant to the Energy Feasibility Study is presented below and was

used in defining research questions and prioritising areas where further research is needed. Some of

this research is being undertaken via detailed investigations on specific energy scenarios and supply

chains, and will be presented in sections 7 and 8.

6.1. Feedback from stakeholders workshops

The following feedback relevant to the Energy Feasibility study was obtained at two stakeholder

events that examined the Nexus Food-Energy-Water in localised food manufacturing. One of this

events took place in London in November 2015 with stakeholders at the national scale (e.g. the

Association for Decentralised Energy, Nestle, Packaging Federation, Waitrose, Innovate UK etc.), and

the other event was held in Oxford in December 2015 and consultees were mainly from the local

food business community in the Oxford area.

The objective of these events was to identify CHALLENGES and OPPORTUNITIES for redistributing

manufacturing in the UK. Among the opportunities outlined were job creation, increased food

security for some products, better and more efficient water and energy use, and potential synergies

for waste heat recovery.

BARRIERS identified by stakeholders included a number of issues linked to business and supply chain

structures, regulation, the cost of local raw materials and labour, availability of space and land for

local food production. For the Energy Feasibility Study the barriers identified that are most relevant

were those linked to the suitability of infrastructure and technology, and the cost and security of

energy supply. Stakeholders asked if the infrastructure and technology for redistributed

manufacturing exist, e.g. small industrial units, smaller-scale technology.

Also it was pointed out that small-scale equipment can be lower efficiency in resource use and may

have higher environmental impacts per unit of production, plus the cost of production may also be

higher than for larger scale manufacturing due to economies of scale. Finance /access to capital to

invest in alternative energy and water technologies as well as new manufacturing equipment was

also highlighted as an important issue, and it was proposed that tax breaks and grants should be

available, for example, for local energy generation in the local food manufacturing sector.

Table 5 below focuses on water and energy aspects and disaggregates into CHANGES and

CONDITIONS the comments made by stakeholders in relation to how to overcome BARRIERS for

localised food manufacturing. ‘Conditions’ were understood to be the factors, circumstances, the

landscape (e.g. policies, regulation, market conditions, trade, business models, funding etc.) that


47

would enable the proposed ‘Change’. Some Conditions are ‘paired’ with the corresponding Change,

but some Changes were proposed with little corresponding discussion among participants about the

Conditions necessary to enable the Change (thus the blank lines).

Table 5 CHANGES AND CONDITIONS relevant for the Energy Study

Changes Conditions

Technology Specific models for different scales/climate change to enable downscaling big systems to small-scale

Integrated and automated technology (e.g. waste by-products, energy, water)

Industrial symbiosis: manufacturing, energy, heat, water

Heat waste recovery technology and energy efficiencies)

Infrastructure (mainly energy and water) Localised energy infrastructure Carbon/climate change levy etc.

Improve energy transmission losses (electricity losses up to 30%)

Renewable and/or localised energy for greenhouses

Integrate systems to manage heat/cold energy networks, water connection, CHPs

Regional economic development through industrial supply chains

Industrial symbioses to help improve energy and water efficiency

Regional economic development through industrial supply chains

Water treatment plants (more research and development of decentralised plants)

Regulation to recover methane for energy, fertilizers and heavy metals

Energy decentralisation Pay more for your energy possible

More wind generation for villages as exchange for free/cheap electricity

Tax incentives, subsidies

Reconfiguration of transport infrastructure for access to markets

Prices Lower cost of retrofitting technologies such as water recirculation

Products prices to reflect the real cost of food, and environmental and social burdens

Policies for triple accounting real costs: food, environmental & social burdens

Policy, planning and regulation Regulation to be more pro-active to minimise energy & water use, and food waste while increasing local jobs.

Need to regulate the front-end (e.g. no overproduction to avoid food waste)

Stronger legislation and regulation e.g. market and innovation (e.g. infrastructure)

Legislative/regulatory framework for full systems needed

Re-organisation of land-use and spatial planning system for local food production (where we grow, build, have green spaces, build localised heating, water recycling drainage etc.)

Legislative framework for local Authorities to drive change, e.g. community heating from heat recovered in manufacturing etc.

New developments such as Northstowe –near Cambridge- to include energy and water efficiency measures

Right planning, regulation and investment


48

Vision Have a vision of co-benefits of localised food manufacturing e.g. training, jobs, housing, urban development, healthier society, experimental food and energy production off-grid as well as on-grid systems etc.

Based on the feedback from stakeholders consulted, the following areas are being investigated in

the Energy Feasibility study in relation to specific supply chains for the chosen study products: bread

and tomato paste (see sections 7 and 8 under development).

Model different shocks to supply chains at various scales /downscaling industrial systems

and supply chains to localised small-scale

Integrated technologies (integrate systems to manage heat/cold, energy networks, water-

energy connections, heat waste recovery technologies)

Energy efficiencies: industrial symbiosis to help improve energy and water efficiency (re-

use/optimise energy, water and also waste/ waste by-products e.g. heavy metals)

Energy decentralisation: potential for localised renewable energy sources (e.g. biomass

/CHPs, solar, energy from waste, more wind generation for villages as exchange for

free/cheap electricity, biogas -recover methane etc.)

Water treatment plants (potential for decentralised plants and links to biogas)

7. Detailed Energy investigation: local energy system

scenarios (including other potential users) (section under

development)

Scenarios development were originally inspired on ‘A vision for 2050’ in the UK’s Low Carbon

Transition Plan


49

Figure 4 Possible future Energy systems. Source: UK’s Low Carbon Transition Plan

8. Evaluate energy generation and storage technologies

suitable for scenarios (efficiency, cost effectiveness,

safety, and environmental impact) (section under

development)

9. Conclusions

Following the literature review, data collection, and stakeholders engagement presented in Sections

2 to 6 of this report, a series of key questions were outlined with the aim of answering these via

detailed investigations presented in Sections 7 and 8. Key questions included:

What are the critical differences between local and centralised bread and tomato paste

manufacturing? E.g. technologies, supply and value chains.

How do centralised and localised bread and tomato paste manufacturing perform relative to

each other – what are the key performance indicators (environmental such as water and

energy savings, decentralisation, transport, employment, waste etc.) that could be used to

compare them?


50

Would buying locally made bread every day, for example, help reducing bread waste, thus

avoiding wasted energy and water? Would this contribute to a reduction in energy linked to

transportation of bread from far away locations?

In response to these questions, results presented in Sections 7 and 8 indicate that:


51

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56

Appendix A Example of Energy questions for semi-structure interviews to local mills

and bakery facilities.

1)-Potential for energy efficiencies/synergies between stages in the milling process. It is

understood that most energy is associated with the Bread baking process thus this has the most

potential in terms of energy efficiencies/synergies between processes, e.g. heat re-use: excess heat

from baking to be used for fermenting stage. However, it is also understood that there is energy

used in the following stages with some potential for efficiencies especially in the conditioning stage:

both for water and energy embedded in potable water and in heating water. Can this be confirmed

for the facility visited?

Grading and cleaning- minimal energy requirements - correct? Perhaps around aspirators sucking air

to remove light dust?

Conditioning (tempering water is added to soften the wheat, making it easier to process):

o Cold conditioning involving soaking wheat in cold water for 1-3 days -some/minimal

implications from embedded energy in potable water

o Warm conditioning involving soaking wheat in 46°C water for 60-90 minutes -

medium implications in terms of energy requirements resulting from embedded

energy in potable water plus energy to warm water to 46°C

o Hot conditioning involves water at 60°C or steam -higher implications in terms of

energy requirements resulting from embedded energy in potable water plus energy

to warm water to high temperatures

Blending: Wheat of different grades and moistures is blended together to obtain a batch with the

required characteristics (the grist) -some energy requirements for mechanical blending

Breaking: the wheat passes through rollers, breaking or cracking open the grain to separate the

interior of the wheat from the outer bran and to separate into three categories -some energy

requirements for mechanical breaking into middlings

Middlings purifier: sieves separate the grain into endosperm, bran and germ.

o Vibrating screen with air blowing up through it to remove lighter pieces of bran

mixed with middlings –some/minimal energy requirements for mechanical

separation of middlings.

Middlings grinding: middlings are ground into flour by large smooth metal rollers. Each time flour is

ground it is sieved to separate it into flours of different fineness, which can be combined as desired

to produce a final product -some/minimal energy requirements for mechanical grinding.

Packing into bags for industrial, commercial or household use -medium energy requirements

associated with packing (?).


57

2)- Where do you think energy could be saved and how? Any additional stages not outlined

above where energy (and water) is used and could be saved?

3)- Any advice / leads on work around local energy technologies/ small-scale renewable

energy in the milling/bakery sector, e.g. another mill or bread manufacturing facility or local

bakery that may be using decentralised sources of energy such as local mill for hydroelectricity

generation, Combined Heat and Power from biomass or Energy from Waste (especially CHPs and /or

EfW where feedstock is mainly agriculture and/or food waste such as wheat by-products, wasted

bread etc.

4)- Do they have data on their energy and water consumption, and would they be willing to share

data? Are they interested in any collaboration to explore possible efficiencies?

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