Energy Efficiency in Urban Water Supplies Need for Web Interactive Tool

Paper Code: ISC/2014/TP/62/2014

Energy Efficiency in Urban Water Supplies

Need for Web Interactive Tool

G Rudra Narsimha Rao1 E Nand Gopal K V Sharma

Industrial Energy Division Industrial Energy Division Centre for Energy Studies The Energy and Resources Institute

(TERI)

The Energy and Resources Institute

(TERI)

Jawaharlal Nehru Technical

University (JNTU) Bangalore, India New Delhi, India Hyderabad, India

[email protected] [email protected] [email protected]

1 Corresponding Author

Abstract – In India the share of urban water utilities’

electrical energy consumption is over 5% of national

electricity production. Energy cost is usually between

50 to 60% of the total operating cost of an urban water

supply system. In urban water supply systems 90% of

this electrical energy is consumed by pumps. The major

component of the life cycle cost (LCC) of pumps is

related to the energy spent in pumping, the remaining

being related to the purchase and maintenance of the

equipment. A small improvement in pumping efficiency

would yield significant reduction in energy

consumption, which would in turn lead to reduction of

carbon emissions to the atmosphere. The data gathered

from urban water pumping stations in various cities

and towns, where energy conservation studies were

conducted in India have been used in the analysis. The

flow rate and quantity of water pumped, the number of

pumps in use, the duration of operation, motor

rewinding history was recorded for each station.

Portable instruments were used for measuring actual

parameters. This paper encapsulates data compilation

and various energy related issues of different urban

water supply system in India. To assist the water utility

staff a web based interactive tool has been developed

for identification of energy cost saving opportunities.

The implications due to the use of such an online tool

and its benefits are deliberated in the paper.

Keywords — Energy efficiency, Urban water supply, Cost

effective solution, Web interactive tool

I INTRODUCTION

In India the share of the urban water utilities’ electrical

energy consumption is over 5% of the national electricity

production. Energy cost is usually between 50 to 60% of

the total operating cost of an urban water supply system. In

urban water supply systems 90% of this electrical energy is

consumed by pumps. Pumping energy cost forms an

important part of the operational cost of water distribution

systems worldwide. Upgrading motors and pumps with

energy efficient ones and properly adjusting them for

system requirement often allow significant energy savings

[1]. Changing the pumping operational procedures is a

very effective way for optimizing its energy consumption

and it does not need any additional investment, the

reduction in energy cost occurs immediately. Efforts to

increase energy efficiency can reduce electrical

consumption for pumping by as much as 5% – 25%, and

sometimes even greater savings are realized [2].

The major component of the life cycle cost (LCC) of

pumps is related to the energy spent in pumping, the

remaining being related to the purchase and maintenance

of the equipment. The issues pertaining to India is different

than developed countries in this particular area. A huge

sum of town municipality budget amount goes for paying

electrical utility bills The cost savings in water supply can

lead to effective quality services (such as education, health,

water and sanitation) to the local communities. One of the

essential elements for optimizing energy cost of urban

utilities is data monitoring and analysis. Understanding of

present tariffs and operational improvements itself results

into a significant cost savings. A small improvement in

pumping efficiency would yield significant reduction in

energy consumption, which would in turn lead to reduction

of carbon emissions to the atmosphere.

In recent years, municipalities in global scenario are

finding it challenging to supply potable quality piped

drinking water due to a phenomenal growth in the urban

population over past five decades. The issues affecting the

water sector include disparity in water supply across

regions, depletion of ground water and undercapitalized

municipalities. The disruption in the monsoon rainfall

pattern and rising energy tariffs has also created problems

in meeting additional water requirement. Municipalities are

spending large portions (40 - 60% of budget) of their

revenues on purchasing energy for providing public

services such as street lighting and water supply [3].

According to a recent Electric Power Survey, the Public

Water Works in India consumes more than 12000 MUs

and Public Lighting consumes 5000 MUs of electricity.

Theoretical studies and practical implementation of

optimal pump scheduling in various types of supply

systems suggest that 10 % of the annual expenditure on

energy and related costs may be saved if proper

optimization methods are used [4]. The objectives is to

analysis the water utility system, and simulate several

scheduling scenarios with optimized pumps in order to

minimize the expenditure related to energy consumption,

based on the demand patterns and associated energy tariffs.


At the same time, there is also a need for creation of

awareness among the operating staff of water utilities on

energy issues, steps for evaluation of their operating

system from energy performance view point, identification

of energy efficiency opportunities and induction of energy

management approaches for integrating better standards

and practices in everyday operation of water utilities.

II MUNICIPAL WATER SUPPLY SYSTEMS

The basic classification of water supply is based on type

of source - ground water and surface water. Ground water

sources (such as wells) indicate that the water is below

ground level or the earth’s surface. Depending on the depth

of the well, a pump may be able to transport the water

directly to the water treatment facility; or else one or more

pumps are needed in series to move water to the treatment

location. The treated water can be pumped to water storage

facilities or pumped directly into the distribution system.

There are two basic types of water supply systems

which are used to create water pressure within the

distribution system are gravity feed system and pumping

pressure system. Difference in elevation between the water

treatment plant and the municipal area to be served, the

water may flow by gravity through the distribution

systems, or there may be the need for another pumping

station. Sometimes a combination of gravity flow and one

or more pumping stations could be suitable and

economical to transport water from the source point to all

the water demand points on the distribution system [5].

The fundamental correlation between water and energy

is not widely understood or adequately exploited through

coordinated holistic efficiency approaches. The water-

energy relationship is based on the reality that treating

water for human consumption and pumping treated water

to the consumer is an extremely energy intensive process.

Every single litre of water that passes through a system

represents a substantial energy cost. A review of demand

management techniques applicable for developing

countries can be found in Vairavamoorthy & Mansoor [6].

One of the energy efficient methods to meet municipal

water demand and flow control, particularly for systems

where static head is a high proportion of the total head, is

to install two or more pumps and operate them in parallel.

A variation in flow rate is achieved by switching on and

off additional pumps to meet the demand. The combined

pump curve is obtained by adding the flow rates at a

specific head. The system curve is usually not affected by

the number of pumps that are running. It is also apparent

that the flow rate with two pumps running is not double

that of a single pump. If the system head was only static,

then the flow rate would be proportional to the number of

pumps operating. Care must be taken when running pumps

in parallel to ensure that the operating point of the pump is

controlled within the region deemed as acceptable by the

manufacturer [7].

III METHODOLOGY

The data gathered from municipal water pumping

stations in various cities and towns, where energy

conservation studies were conducted in India, have been

used in the analysis [1]. The flow rate and quantity of

water pumped, the number of pumps in use, the duration of

operation, motor rewinding history was recorded for each

station. The actual flow rate of water, inlet and outlet

pressures at the pump, power consumed at each installation

were measured using the following instruments:

• Portable load manager to monitor and log the

transformer parameters (Voltage, current, power factor,

kW, kVA, kVAr, Hz, kWh);

• Clamp on electrical power analyzers to measure and

log the individual motor parameters (Voltage, current,

power factor, kW, kVA, kVAr, Hz, kWh);

• Ultrasonic water flow meter to measure the velocity

and flow rate of water at the pump and in piping system;

• Digital pressure sensor to measure the delivery head

of the pumps.

Motor characteristics curves for various ratings

collected from the manufacturers and used during the

analysis. The above measurements and analysis carried out

for over 433 pumps of different ratings (connected motor

to pumps 11 kW to 2600 kW) installed across 98 pumping

stations in five states in India are given in Table 1.

Table 1 Details of pumping stations used for analysis

City / State

No. of

pumping

stations

No. of

pumps

(Operation)

Annual Energy

Consumption,

million kWh

Bangalore 9 67 179

Delhi 7 49 129

Pune 6 38 76.7

Vishakhapatnam 4 13 48.7

Andhra Pradesh

(2

Municipalities)

5 16 3.5

Karnataka

(11

Municipalities)

26 46 62.4

Tamil Nadu

(25

Municipalities)

41 204 41.7

It was observed that water scarcity is significant in

many locations and in some cases it is seasonal in nature.

Most of the water pumping stations was not equipped with

measuring devices to know the actual performance of the

systems.

IV DATA ANALYSIS AND ENERGY SAVING

POTENTIAL

A selection 16 municipality, based on population

coverage to suit Indian towns has been done via sampling.

Analysis of these16 towns/cities is presented in this

section. The collected data was analyzed based on the

water availability at the source and the present installed

capacity of the pumping stations. The comparison of the

per capita figure against the all India norms of 135 LPCD

(litres per person per day) water supplies reveals the

deviation from this norm at these municipal towns.

As seen from the above chart the difference in the

amount of water received varies largely from town to

town, and 75% of the towns receive less than the all India


norms fixed by the government. A major reason for this is

the non-availability of water at the source. It is also not

unusual that the schemes with low installed capacity

integrate bore-well water at numerous locations within the

municipal vicinity area. In various cases these bore-wells

are hand operated.

Figure 1 Classification on the basis of per capita water

supply

The comprehensive detailed study revealed that

significant potential exists in municipal water pumping

installations in terms of improving the energy efficiency.

The details of energy and cost savings identified, as a

result of the energy audit is classified in terms of the

percentage saving potential, are given in figure 2.

Figure 2 Percentage energy saving potential

The costs that can be saved by implementing energy

saving measures can be utilized for the following

initiatives:

Improved water quality deliverables to the end

users

Better maintenance and house-keeping practices

Advanced metering and monitoring facilities

Creating awareness programmes on energy

efficiency in other/neighboring municipalities

Some of the additional benefits could include

Improved quality of water

Better hygienic conditions

Improved accounting of water

Awareness among municipal staff on energy

efficiency issues which leads to better

operations

The energy that is saved at the user end directly has an

impact at the generation end. If 100 units of fuel input is

available (say coal based plant) and considering the typical

efficiency available for intermediately systems / equipment

like transmission & distribution, motor, pump, throttled

valve & pipe losses etc., the units finally available at end

user such as a water utility would be only 9.6 units after

accounting for built-in efficiencies of the equipment in

between systems (shown in Figure 2.13) i.e., 100 units of

fuel input would finally reaches as 9.6 units at motor

terminal (100x0.096) due to several system efficiencies up

to user point (0.3 x 0.85 x 0.9 x 0.75 x 0.7 x 0.8) of various

systems. A typical power supply system where the water

pumping installation is the final consumer is shown in

figure 3.

For every unit saved at the pumping station, generation

can be reduced by almost 9.6 times since there are several

intermediary players for the power to reach the end users.

Generally for every unit produced in coal based power

plants reduces the emission by almost 0.78 kilograms [7].

The figure depends on the efficiency of coal based power

plants and the station heat rates.

As per the Central Electricity Authority report on 17th

Electric Power Survey, the annual energy consumption of

water supply systems is 12,000 million units. A 10%

reduction in energy consumption by incorporating energy

efficiency measures will amount to 1,200 million units

reduction in energy at the user end thereby yielding 11,520

million units reduction potential at the generation end. The

GHG emission reduction potential works out to 9.33

million MTCO2e annually.

V WEB INTERACTIVE MONITORING TOOL

A monitoring tool has been developed to capture basic

infrastructure details of municipal water pumping systems

(such as electrical system and its prevailed tariff structure,

pumps and its configuration, specifications etc.). These

details can be entered along with registration. A back end

data base storage has been created which captures all the

entered monthly details (billing details, operating hours,

number of pumps in use etc.). A comparative analysis is

carried out based on operational data versus design (or)

allocated data applicable to a particular pumping station.

The results are displayed in terms of graphical

representation which can be viewed and understood by the

operating staff (skilled or unskilled). Depending upon the

available instrumentation / information pumping station

level data can be entered. It can be analyzed on a monthly

and daily basis.

The tool is a web interactive mode of operation with

availability of expert services which is optional, where

municipal utility staff can pose questions to the experts

based on the data furnished. The technical expert team also

can view the furnished data and provide free advisory

services through mail (or phone). This will help the

municipal staff to take necessary steps to enhance the

pumping system operating efficiency. Some of the screen

shots of online interactive tool are furnished in figure 4.


Figure 3 Typical supply

Ratio 1 : 0.25 Ratio 1 : 4.5

ɳ=

80% pipe

Input Fuel 100 units

ɳ= 30%

power plant

ɳ= 85%

T&D

Drive system (from meter to

input shaft of machine)

ɳ= 90%

motor

Applications

ɳ=

75% pump

ɳ=

70% valve

Water pumping system with proper design

Utility system up to water pumping installation

Interest of boundaries to public, which also cares about cost of generation utility to water pumping

system

End use (flow)

Thermal Power Plant

Transmission Distribution Utility Meter

Motor

Pump

Main

Pipeline

Valves

Transmission Piping



Figure 4 Snap-shot of web interactive tool (seven shots)

Energy conservation measures such as utilization of

contract demand (including penalty), power factor

management, operation of pumps (with respective to

piping networks) and drop in pumps operating efficiency

are analyzed for corrective action using the web based

monitoring tool. The details of computer aids used in

developing the web based interactive tool are given in table

2.

Table 2 computer aids are used in upgraded version

Language C# .Net

Web UI ASP.Net

IDE Visual Studio 2012

Framework .Net 4.5

Database MySQL 5.0

VI RESULT AND DISCUSION

A majority of the municipalities in India are not

familiar with new concepts and technologies available in

the market, due to lack of education and training.

Municipalities should make it as part of their work culture

to educate ground-level as well as supervisory staff on

energy, water and technologies that are available to

improve efficiency. Inefficiencies should be pointed out

and figures should be converted into their rupee

equivalents, and given in terms of hour, day, and year.

Educating the staff on these figures will result in cost-

effective initiatives emerging from the ground level staff

members who operate the system.

Most municipal personnel follow a routine working

pattern rather than going a step further. The routine

working pattern can be attributed to lack of individual

commitment, and most importantly and absence of


motivation from seniors. A human resources team should

be formed for these assignments, whereby the working

personnel become aware of the bottlenecks and take

necessary actions towards improving energy efficiency.

Moreover, a back-up support from the top-level

management can bring about miraculous results towards

achieving higher efficiency.

Time series data pertaining to energy consumption,

cost of energy inputs and other related data like quantity

water pumped, which has a bearing on energy

consumption, should be collected. Historical data available

with the utilities for major equipment including billing

systems needs to be studied. Information on inventory of

the electrical / mechanical equipment installed and its

operating parameters (like hours of operation of pumps,

actual load in kW etc.) should be collected. These data

should be compared with the design/operating values and

margins for improvement can be found out.

The online web interactive analytical tool is a step

forward towards addressing municipal staff awareness /

training / skill development for energy cost savings of their

respective municipal water system. Energy efficiency

studies have established that energy costs account for 40 to

60% of the operating expenses for supplying water. By

becoming energy efficient, each municipal water system

can reap a minimum energy savings of 25 to 40%. This

translates to an energy savings of at least 3000 MUs (based

on the data that public water works in India consumes

more than 12000 MUs), which means that one can avoid

the need for an additional capacity of 500 MW for the

Indian scenario.

The case studies presented below are from

Municipalities of two states from southern India: Andra

Pradesh and Karnataka. The case studies are broadly

divided into 3 categories:

Electrical systems and drives

Pumping system

Operational and other aspects

Details some of the case studies are presented in table 3.

Back Ground Energy

Conservation

Measure

Realisation

saving potential

Fine tuning of the existing contract demand to meet

the present loading conditions

Contract

demand of 1000

kVA

Minimum

billing demand

80%

Measured

instantaneous

CD 172 kVA

Reduction of

the contract

demand to 300

kVA

Surrendering

700 kVA

Demand

saving of 650

kVA

Amounting to

Rs. 15.21 lakhs

annually

Installation of capacitors to improve power factor (pf)

and reduce kVA demand

Average pf

0.83

Penalty Rs

4.32 lakh/yr

110 kVAr

bank installed

Install 125

kVAr

additional

Improve pf to

0.95

Demand

reduction by

101 kVA

Annual

demand saving

Rs 2.18 lakh

20 kVAr bank

not working

Annual

saving by pf Rs

4.32 lakh

Suitable sizing of booster pumps

2 centrifugal

pumps installed

for booster

8km from

reservoir

Rated 660 lps

@ 62m

Measured 670

lps @ 46m and

710 lps @ 46m

Operating

efficiency 61%

and 64%

Head

mismatch 16m

Replace with

710 lps @ 48m

pump

Overall

efficiency 80%

Reduction in

power 84 kW

7.3 lakh kWh

energy saving

Annual

saving Rs 25

lakh with

investment of

Rs 10 lakh

Modification in the existing piping network for

enhanced water flow

4 centrifugal

pumps in

parallel

Each Rated

15.86 MGD at

50 Hz

Drawing

14.23 MGD

15% deficit

Output

enhanced by

modifying

header system

Additional 1.4

MGD drawn

after

modification

Reduction in

specific energy

consumption by

8.6%

Annual

energy saving

5. Lakh kWh

Amounting to

Rs 20 lakh

Improving the main water flow distribution system

Detailed flow

pattern carried

out

Assess water

loss due to

leakage

37% leakage

Reducing the

leakage level <

10%

Annual

energy saving

5.3 lakh kWh

Amounting to

Rs 21 lakh

Cost of

implementation

Rs 2 lakh only

VII CONCLUSION

Energy costs are typically the highest or second highest

governable costs for water utility operations. Using new

developments in the area of pumps allows for initially

selecting a pump to match the expected performance

requirements and then maintain optimal performances

through periodic refurbishment. These measures realize

energy cost savings, it is not necessary that electrical

system part designed to suit local conditions (tariff

structures).

From the study it is clear that a tremendous energy

saving potential exists in these municipal water pumping

installations. One of the interventions needed is to train

and create awareness among the municipal utility staff

about the benefits of energy efficiency improvement. In

order to help and assist these staff with available

resources/information an online web interactive monitoring

tools has been developed. The tool will help in better

understanding of their municipal water system and changes

required for realizing energy cost saving opportunities time

to time. Municipalities can utilize the energy cost savings

accruable as a result of implementing energy efficiency

measures for any other important services like health,

education which are equally important in sustainable

development.


ACKNOWLEDGEMENTS

The authors would like to acknowledge the support of

all water utilities for sharing the data and allowing us to

perform the study. Our sincere thanks to all who were

directly or indirectly involved in the study and analysis.

Finally we wish to acknowledge the support of all the

TERI team members who were involved in the detailed

study of all the water utilities in states of India and other

developing countries.

REFERENCES

[1] TERI, “Best Practices Guide: Energy Efficiency in

Municipal Water Pumping, Bangalore”, India. 2009,

pp. 59-71

[2] IFC. Manual for Development of Municipal Energy

Efficiency Projects, International Finance

Corporation, 2007, pp. 03

[3] IFC, “Manual for Development of Municipal Energy

Efficiency Projects”, Washington D.C. 2007

[4] Rao, G.R.N, Sharma, K.V. Energy conservation

opportunities in municipal water supply systems: a

case study, Resources, Energy and Development,

9(1), 2012, pp. 35-48

[5] Rao, G.R.N, Nand Gopal, E, Sharma, K.V. An

Optimization Algorithm for Energy Efficiency in

Municipal Water Supply Utilities in Developing

Countries, International Conference on Advances in

Energy Research, IIT Bombay, Mumbai, 2013

[6] Vairavamoorthy, K., Mansoor, M.A.M, Demand

management in developing countries. In: Butler, D.,

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ISBN:1843390787, 2005

[7] BEE, “Guidebook: Electrical Efficiency in Electrical

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[8] CEA, “CO2 Baseline Database for the Indian Power

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17

[9] K. E. Lansey and K. Awumah, “Optimal pump

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[10] TERI, Report Municipal Energy Efficiency Outreach

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[12] UNFCCC, White Paper “Climate Change and Water

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[13] Halpeth, M K. “Emerging Trends in Energy

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Energy Efficiency in Urban Water Supplies Need for Web Interactive Tool