The Coal Handbook: Towards Cleaner Production || Future directions toward more efficient and cleaner use of coal

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  • Woodhead Publishing Limited, 2013

    497

    18 Future directions toward more efficient and

    cleaner use of coal

    D. G. OSBORNE and M. SHARPLES, Xstrata Technology, Australia , L. LIEN, United Finance and Management Services, USA , G. SCHUMACHER, NRG Gladstone Operating Services, Australia ,

    A. BABICH, RWTH Aachen University, Germany , D. HARRIS and J. CARRAS, CSIRO Energy Technology, Australia

    DOI : 10.1533/9781782421177.3.497

    Abstracts : Many eminent coal technologists perceive a shift towards integrated coal utilisation complexes that could one day convert coal into clean, ready to use energy, produce cost-effective reductants for steelmaking, and simultaneously generate an array of useful chemical feed-stocks or products, whilst still achieving environmental compliance. Is this feasible of just a pipedream? The chapter explores this and covers the future trend as it is perceived refl ecting on the changing energy scene and considering all energy sources. Current practices involve a series of distinct supply chains that lead to designated coal brands being passed from the supplier (producer) to the buyer (user) with very little collaboration or cooperation. Such practices minimise the potential for optimisation of the outcome and/or sustainability of the resource. An optimisation approach is important in order to set the scene for innovative concepts such as the modifi ed supply chain with the shift towards gasifi cation and transportation as SNG/LNG cargoes instead of bulk shipment including water and waste that are becoming increasing controversial, particularly in terms of regulatory controls and waste disposal. The ultimate outcome could be a move towards poly-generation, the integrated coal driven factory/refi nery that produces power, chemicals, steel, ash-based by-products, refractories, etc., all on one site.

    Key words : coal utilisation, supply chain, integration, optimisation, poly-generation, emerging coal technologies.

    18.1 Introduction

    In this fi nal chapter several expert authors come together to describe a per-ceived shift towards new, integrated coal utilisation complexes that could one day convert coal into clean energy, produce cost-effective reductants for steel-making, and simultaneously produce an array of useful chemical feed-stocks or products, whilst still achieving environmental compliance. Is this feasible or just a pipedream? The chapter explores this and covers the future trend as we see it and initially refl ects on the changing energy scene considering all energy sources. Current practices involve a series of distinct endeavours that

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    lead to designated coal brands being passed from the supplier (producer) to the buyer (user) with very little collaboration or cooperation. Such practices minimise the potential for optimisation of the outcome and/or sustainabil-ity of the resource. This optimisation approach is important in order to set the scene for innovative concepts like the modifi ed supply chain with the shift towards gasifi cation and transportation as SNG/LNG cargoes instead of bulk shipment including water and waste that are becoming increasingly controversial, particularly in terms of permitting and disposal. The ultimate outcome should perhaps be a move towards polygeneration, the integrated coal driven factory/refi nery that produces power, chemicals, steel, ash-based by-products, refractories, etc., all on one site.

    One of the greatest uncertainties in climate prediction is the amount of CO 2 that will ultimately be released into the atmosphere. Ken Caldeira, a climate scientist at Stanford University, asks how much CO 2 will be released into the atmosphere if we assume that industrial civilisation will continue to do what it has been doing for the past 200 years, namely burn fossil fuels at an accelerating rate until we can no longer afford to extract them. 1 Current predictions suggest over one quadrillion tonnes of carbon is currently locked up in the Earths sedimentary deposits. So far, we have used only about 0.05% of this which has produced about 2000 billion tonnes of CO 2, so real-istically that we will never run out of fossil fuels or use up all of the carbon in the Earths crust. In addition to coal, oil and gas, we are also extracting oil from tar sands and gas from fractured (fracked) oil shales; both resources were once considered economically and technologically inaccessible. It is therefore hard to imagine how far technology might take us, but it is prob-ably fair to assume that coal will remain the most competitive option and will continue to be used until the cost of extraction and processing become uneconomical compared to other energy options. By this time, perhaps more than 100 years from now, climate conditions will have changed sig-nifi cantly even if the majority of the CO 2 is eventually successfully seques-tered. Already, global temperatures have risen by almost 1C and average temperatures could conceivably continue to rise by 10C, more than enough to melt the ice in the glaciers of Greenland and at the polar icecaps. This would cause water levels to be raised by 120 m and atmospheric concen-trations would reach levels last reached somewhere in the mid-Cretaceous period (~100 million years ago). Perhaps this transition will occur again and mankind will gradually adapt to it. There is a very clear and strong tendency to fi nd alternative solutions involving coal free and carbon lean technolo-gies, especially in Europe. Therefore the main objective for this outlook, from the point of view of the contributing authors, is to provide analysis and discussion as to where, why and to what extent coal will be irreplaceable in the future and how coal should be used in more environmentally friendly or carbon conscious ways.

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    18.1.1 Current coal reserves, resources and consumption

    Globally, coal is the most abundant fossil fuel, with total reserves over 1 trillion tonnes in energy terms, approximately 3.2 and 2.5 times larger than those of natural gas and oil. The coal resources are signifi cantly larger and more geo-graphically diverse than the current reserve base, and as market conditions change and technology advances more of the coal resources are converted into reserves. Even though there has been a signifi cant increase in international coal prices since 2005, continued depletion of lower cost mining seams and the need to move towards deposits which are more challenging or more distant from existing infrastructure has led to a signifi cant increase in overall mining costs, since from 2005 the weighted-average coal mining costs has increased by around 12% per annum. This balance between mining investment/operational costs and international coal prices will be the ultimate driving factor in deter-mining which resources are eventually converted into reserves and the cost effectiveness of coal compared to alternative sources of primary energy.

    In terms of reserves/resources and supply and demand the BP annual statistical review of energy sources provides a valuable insight as to the state of play in coal reserves, recovery and usage. It includes so-called proved reserves of coal which are generally taken to be those quantities that geo-logical and engineering information indicates with reasonable certainly can be recovered in the future from known deposits under existing economic and operating conditions. Proved coal reserves for anthracite and bitumi-nous (including brown coal) and sub-bituminous and lignite are shown in Fig. 18.1 all data are measured in million tonnes.

    6.41.4 41.4

    22.8

    27.9

    26.2

    28.5

    3.81.5

    35.5

    30.9

    5.82.2 36.1

    2001Total 984453million tonnes

    Distribution of proved reserves in 1991, 2001 and 2011Percentage

    2011Total 860938million tonnes

    29.7

    1991Total 981780million tonnes

    Europe and EurasiaAsia PacificNorth AmericaMiddle East and AfricaS. and Cent. America

    18.1 Distribution of proved reserves in 1991, 2001 and 2011. ( Source : BP Statistical Review of World Energy 2012.) 2

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    300

    250

    200

    150

    100

    50

    NorthAmerica

    World proved reserves of coal in 2011 were sufficient to meet 112 years of global production, by far the largest R/P ratio for any fossil fuel.Europe & Eurasia holds the largest regional reserves and has the highest R/P ratio. The Asia Pacific region holds the second-largest reserves, while North America has the second-highest R/P ratio.

    S. & Cent.America

    Europe &Eurasia

    Middle East& Africa

    AsiaPacific

    0 91 96 01 06 11 0

    100

    200

    300

    400

    500

    600

    700

    Reserves-to-production (R/P) ratiosYears

    2011 by region History

    North AmericaS. and Cent. AmericaEurope and EurasiaMiddle East and AfricaAsia PacificWorld

    18.2 Reserves-to-production (R/P) ratios ( Source : BP Statistical Review of World Energy 2012.)2

    Production by regionMillion tonnes oil equivalent

    Consumption by regionMillion tonnes oil equivalent

    Asia PacificAfricaMiddle EastEurope and EurasiaS. and Cent. AmericaNorth America

    Asia PacificAfricaMiddle EastEurope and EurasiaS. and Cent. AmericaNorth America

    4000

    3500

    3000

    2500

    2000

    1500

    1000

    500

    4000

    3500

    3000

    2500

    2000

    1500

    1000

    500

    86

    Coal was again the fastest-growing fossil fuel. Global production grew by 6.1%. The Asia Pacific region accounted for 85% of globalproduction growth, led by an 8.8% increase in China, the worlds largest supplier. Global coal consumption increased by 5.4%, withthe Asia Pacific region accounting for all of the net growth. Elsewhere, large declines in North American consumption were offsetby growth in all other regions.

    91 96 01 06 11 0 86 91 96 01 06 11 0

    18.3 Production and consumption by region. ( Source : BP Statistical Review of World Energy 2012.)2

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    R/P ratios represent the length of time that those remaining reserves would last if production were to continue at the previous years rate. It is calculated by dividing remaining reserves at the end of the year by the production in that year. Reserves-to-production (R/P) ratios are available by country and feature in the table of coal reserves. R/P ratios for the region and the world are depicted in Fig. 18.2. Coal reserve data is in million tonnes.

    In 2011, see Fig. 18.3, global coal consumption rose impressively by 5.4% (192 mtoe). Since 2003 average global coal consumption increased by 4.8% per annum, with most of the increase in coal consumption being spurred by the rapid development of the Asian and Indian markets, in particularly China which averaged 10.4% per annum or 84% of the total growth over the same period. The picture of growth in global coal production closely refl ects the increase in coal consumption, with the majority of production increases focused in the Asia-Pacifi c region. Since 2003, average global coal production has increased by 5.3% per annum, of which China grew at 9.7% per annum or 74% of the total production growth over the same period. The graph below illustrates the regional consumption by region in million tonnes oil equivalent (mtoe).

    The methodology behind the review is that coal production includes data for solid fuels only included in the hard coal category are bituminous and anthracite; the sub-bituminous coal includes both lignite and brown coal.

    18.2 Future role of coal in the global economy

    Before discussing the future of the role of coal, it is fi rst worth considering what the author considers to be the key foundation issues impacting the role of coal in the worlds economy:

    1. At present there is no practical alternative to coal that will meet the worlds energy needs;

    2. Economically and environmentally sensible energy is the foundation for the continued health and economic well-being of the people of the earth. In addition, electricity is the most essential form of energy for human welfare;

    3. Government intervention in the market to address the climate change issue may be a signifi cant impediment to coals longer-term prospects;

    4. Lessons have been learnt in the past of over-reliance on a relatively scarce, geopolitically risky energy source but are often forgotten over time;

    5. To cover the future world energy demand, all available energies need to contribute. Discriminating against coal amongst the various comple-mentary energy sources simply on the grounds of development policy would be unwise.

    The key international agency which assesses global primary energy demand is the International Energy Agency (IEA) based in France, which pub-lishes a comprehensive overview of policy developments, energy supply and

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    demand balances and a primary energy outlook for the next 25 years. The IEA is primarily funded by OECD governments to assess energy demand in conjunction with pricing scenarios and resources availability. They assess the threats and opportunities facing the global energy system based on quantitative analysis of energy and climatic trends to create three global energy demand scenarios: Current Policies, New Policies and 450 Scenario. These scenarios are constructed in order to assess potential economic and energy pathways which can therefore be used in setting government policies to manage growth and environmental outcomes.

    1. Current Policies Status quo assumes no new policies are added to the current ones in place (mid-2011 at the time of writing).

    2. New Policies Partial reform assumes recent government policy com-mitments (i.e. Kyoto agreement and other global/country greenhouse gas commitments) are implemented in a cautious manner.

    3. 450 Scenario Full reform assumes global compliance to the target to limit long-term increase in the global mean temperature to two degrees Celsius above pre-industrial levels.

    Figure 18.4 shows the wide difference in outcomes between the three sce-narios and the dramatic impact government policies have on the future demand growth for coal.

    In summary, continued global economic growth and the continued eco-nomic development of the worlds emerging economies require increased electricity production to support growth. The generation method for

    8000

    Mtc

    e

    Rest of world Current policiesscenario

    14%

    47%

    14%

    50%

    1883 Mtce

    2550 Mtce

    New policiesscenario

    450 scenario

    India

    China

    7000

    6000

    5000

    4000

    3000

    20001980 1990 2000 2010 2020 2030 2035

    18.4 Global coal production by region, Mtce*. ( Source : IEA Outlook, 2011 .) *Includes hard coal (coking and steam coal), brown coal (sub-bituminous coal and lignite...

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