1. Quantification of
Water Energy and Carbon Nexus
Kathmandu, Nepal
25—29 September, 2012
Dr. Sangam Shrestha
Asian Institute of Technology (AIT), Thailand

2. Session objectives
• To understand how water energy and carbon
emission are linked
• To estimate the energy use for water services, water
use for energy production and carbon emissions
• To present and discuss about the water energy and
carbon nexus by considering hypothetical example

3. Outline
• Water Energy and Carbon nexus: Overview
• Cyclic effect of water energy and carbon nexus
• Energy uses for water services
• Water use for energy productions
• Water energy and carbon emission
• Example
• Exercises

4. Water Energy and Carbon Nexus
• Water and Energy has symbiotic relationship.
• Production and consumption of water involve energy use
and energy production require water for consumptive as
well as non- consumptive use.
• Energy associated with water use is also responsible for
emission of GHG.
• Clean energy adopted for reduction of GHG may have
substantial water requirements hence water-energy-
carbon nexus should be quantified more precisely for
resource use optimization.
• Saving water is saving energy – saving energy reduces
emission of GHG.

5. Water Energy and Carbon Nexus
Source: US Department of Energy, December 2006.

6. Impact on climate
(climate change)
Water for Energy
Water Scarcity
in city
Energy For Water More Water / More Energy/
More Carbon
Figure: WEC Nexus in City and its Implications

7. Why do we need to know
Water Energy and Carbon Nexus?
• The rapid increase in population and extensive economic
development in cities has increased the demand for
adequate amount of water and energy. An increase in
water use requires more energy and demand for more
energy in turn requires more water. Both of this has
impact on GHG emissions.
• The challenge of climate change and reduction of GHG
emissions and stabilize their levels in the atmosphere is
globally recognized.
• Integration of water and energy policies into a single
framework is necessary for resource use optimization and
this in turn demand proper estimation of water energy
and carbon linkage.

8. Cyclic Effect of WEC Nexus Increase in urban
population
Increase in water
Demand
More Energy
Required for Water
production in City
Increase in Energy
consumption as well
as demand
New Water
alternatives
• Groundwater
• Desalinization More use of fossil
fuel
• Inter Basin transfer
Global Warming /
Climate change Increase in GHG
• Draught Emission
• Need more water
due to
temperature rise

9. Water footprint of energy
• A water footprint is the amount of water consumed by
any sector for their purpose. Water is required for
consumptive as well as non consumptive use in power
generation process, as source of kinetic energy in
hydropower and coolant in case of nuclear and thermal
plant.
• Water is used at various stages of the power generation
cycle, including fuel extraction (mining and refining, oil,
gas, uranium and coal processing, coal and gas
liquefaction and gasification, carbon sequestration) and
generation (coal, gas, oil, nuclear and biomass power
plants).

10. Water Use for Energy
TABLE: WATER USE FACTOR FOR DIFFERENT SOURCE OF
ELECTRICITY
Electric Fuel Total Water Use
(Litres/MWh)
Withdrawal Consumption
Coal 60,763 2,620
Natural Gas 24,545 651
Nuclear 56,066 2,165
Solar Thermal 3,028 3,028
Geothermal 2,650 2,650
Photovoltaic Solar 874 8
Wind <240 <4
Biomass N/A N/A
Modified From: (Klein g. , 2009; Wilson, Leipzig, & Griffiths, 2012)

11. Water consumption by fuel source (including Hydropower)
40
35
30
Litre/Kwh
25 Consumption
20
15
10
5
0
Coal Hydroelectric Natural Gas Nuclear Solar Thermal Geothermal Photovoltaic
Solar
Modified from: (Wilson, Leipzig, &
Griffiths, 2012)
Source of Energy

12. Energy Use for Water Services
• Energy is required to:
• lift water from depth in an aquifer
• pump water in pipes
• treat waste water
• desalinate brackish or sea water
• Globally, commercial energy consumed for delivering
water is more than 26 quads, 7 percent of total world
consumption.
• A considerable amount of water is also delivered by
utilization of human energy – e.g., use of treadle pumps
and water transport by women and children.

13. Energy Use for Water Services

14. TABLE : ENERGY USE FACTOR FOR DIFFERENT STEPS OF
WATER SUPPLY
Range of Energy
Intensity
Water Use Cycle Segments
(kWh/ML)
Low High
Water Supply and Conveyance 0 3,698
Water Treatment 26 4,227
Water Distribution 66 317
Wastewater Collection and
Treatment 185 1,215
Wastewater Discharge 0 106
Recycled Water Treatment and
Distribution 106 317
Modified from: (Wilson, Leipzig, & Griffiths, 2012)

15. Energy Use : Major contributor of GHG
Figure : GHG Emissions from Different Sector (WRI, 2009)

16. WATER ENERGY AND CARBON IN A CITY
Example:
Let us consider four different cities (A,B,C and D) using
same amount of electric energy from different power
production system as shown in table below:
Energy Used (MWh)
Water
GHG Emission City
Electric Fuel consumed
(Litres/MWh) Kg CO2 eq/MWh A B C D
Coal 2,600 484 8,900 50,000 4,000 6,000
Diesel 2,200 380 8,000 16,000 16,000 2,800
Natural Gas 651 270 - 4,000 3,000 14,000
Nuclear 2,165 140 680,00 8,400 30,000 17,000
Wind 3 14 - 500 2,000 4,600
Hydropower
35,000 80 4,000 10,000 33,900 44,500
(Reservoir)
Total 88,900 88,900 88,900 88,900

17. SAME AMOUNT OF WATER IS SUPPLIED TO THE CITY FROM
DIFFERENT SOURCES WHICH CONSUME ENERGY AS SHOWN IN
COLUMN (I).
Energy Water Supplied to city (ML)
Source Types Intensity
(Kwh/ML) A B C D
(i) (ii) (iii) (iv) (v)
Surface Water 320 40,000 20,000 10,000 8,000
Groundwater 520 10,000 8,000 30,000 25,000
Brackish Groundwater 840 2,000 0 6,000 9,500
Desalinated Seawater 3,500 0 9,000 0 5,000
Recycled Water 390 0 150,00 6,000 4,500
Total 52,000 52,000 52,000 52,000

18. QUERIES
• How much water is consumed by energy
sector?
• How much carbon is emitted by energy
sector?
• How much energy is consumed by water
sector?
• Compare the results from four cities.

19. Solution: Water consumption and GHG emissions to supply
same amount of energy (88,900MWh) from different sources
A B C D
Water GHG Water GHG Water GHG Water GHG
Electric Fuel consumed Emission consumed Emission consumed Emission consumed Emission
ton CO2 ton CO2 ton CO2 ton CO2
ML ML ML ML
eq eq eq eq
Coal 23 4308 130 24200 10 1936 16 2904
Diesel 18 3040 35 6080 35 6080 6 1064
Natural Gas 0 0 3 1080 2 810 9 3780
Nuclear 147 9520 18 1176 65 4200 37 2380
Wind 0 0 0 7 0 28 0 63
Hydropower
140 320 350 800 1187 2712 1561 3568
(Reservoir)
Total 328 17,188 536 33,343 1,299 15,766 1,629 13,759

20. Solution: Total energy use to supply same amount of water
(52,000ML) from different sources
Water Supplied to city
Total Energy used (MWh)
Energy (ML)
Source Types Intensity
(Kwh/ML) A B C D A B C D
(i) x (i) x (i) x (i) x
(i) (ii) (iii) (iv) (v)
(ii) (iii) (iv) (v)
Surface Water 320 40,000 20000 10,000 8000 12800 6400 3200 2560
Groundwater 520 10,000 8000 30,000 25000 5200 4160 15600 13000
Brackish
840 2,000 0 6,000 9500 1680 0 5040 7980
Groundwater
Desalinated
3500 0 9000 0 5000 0 31500 0 17500
Seawater
Recycled Water 390 15000 6000 4500 0 5850 2340 1755
Total 52,000 52,000 52,000 52,000 19,680 47,910 26,180 42,795

21. COMPARISON OF RESULT
Water consumed GHG emission by Total energy
to produce diff. source of used by water
City electricity electricity supply
ML ton CO2 eq (MWh)
A 328 17188 19,680
B 536 33343 47,910
C 1299 15766 26,180
D 1629 13759 42,795

22. Water consumed
to produce electricity (ML)
2000
Million Litres
1500
1000
500
0
A B C D
Cities
• Water consumption is highest in City D as major source
of energy is from Hydropower.
• Water consumption is lowest in city A as major source of
energy is from nuclear.

23. Total energy
used by water supply (MWh)
60,000
50,000
40,000
MWh
30,000
20,000
10,000
0
A B C D
Cities
• Total energy used is highest in City B as major source of
water is desalinated seawater.
• Total energy used is lowest in city A as major source of
water is surface water.

24. GHG emission by
diff. source of electricity (ton CO2 eq)
40000
ton CO2 eq
30000
20000
10000
0
A B C D
Cities
• GHG emission is highest in City B as coal a major
energy.
• GHG emission is lowest in city D as hydropower is a
major source of energy.

25. Exercise
• Groups: 4 (A,B,C,D)
• Calculation: 10:30-11:00
• Presentations: 15mins/group
• Group A:11:00- 11:15
• Group B: 11:16- 11:31
• Group C: 11:32-11:47
• Group D: 11:48-12:03
• Wrap up:12:05-12:15

26. Problem
• Assume a hypothetical city that uses a total of 8,000MWh of
energy and water supply of 4,500ML. Please estimate the
total water consumed to produce the energy, total energy
consumed to supply the water and GHG emissions related to
energy generation. Consider six sources for electricity
generations i.e. coal, diesel, natural gas, wind and
hydropower. For the water supply please consider the sources
as surface water, groundwater, brackish groundwater,
desalinated sea water and recycled water. Discuss atleast 3
scenarios with different combination of energy sources and
water sources.
• Please discuss the implications of different sources of energy
use and water consumption and GHG emissions.
• Conversion factors are given in xls sheet.

27. Group division
Group A
Name Country
Ms. Gul Pari Mohammadi Afghanistan
Mr. Md Ahmedul Azam Bangladesh
Mr. Aaditya Kumar Bhaskar India
Mr. Wahyu Septiono Indonesia
Ms. Muna Thapa Nepal
Ms. Reshna Udas Nepal
Ms. Jyotsna Shrestha Nepal
Mr. Sagar Aryal Nepal
Ms. Bureera Sabir Pakistan
Mr. Tawin Kim Thailand
Group B
Name Country
Ms. Laura Jayne McManusa Australia
Ms. Dechen Yangzom Nedup Bhutan
Ms. Rozita Singh India
Ms. Ika Zahara Qurani Indonesia
Ms. Sangita Biswakarma Nepal
Mr. Dinesh Panday Nepal
Mr. Mohan Bahadur Chand Nepal
Mr. Radha Krishna Dhital Nepal
Mr. Qasim Abbas Bhatti Pakistan
Ms. Saengabha Srisopaporn Thailand

28. Group C
Name Country
Ms. Marufa Ishaque Bangladesh
Mr. Sonam Phuntsho Bhutan
Ms. Malika Munjal India
Mr. Kei Fujihira Japan
Ms. Nirmala Singh Bhandari Nepal
Ms. Samridhi Rijal Nepal
Mr. Chandra Bhandari Nepal
Ms. Shanti Kandel Nepal
Ms. Rizza Mendiola Philippines
Ms. Tuong Huyen Tram Vietnam
Group D
Name Country
Ms. Chap Sopornetra Cambodia
Mr. Souran Chatterjee India
Mr. Sushant Sharma India
Ms. Palwasha Habib Pakistan
Ms. Sujata Singh Nepal
Mr. Shankar Adhikari Nepal
Mr. Manoj Yadav Nepal
Ms. Sumaiya Tabassum Ahmed Bangladesh
Mr. Ramachandran Niroshan Sri Lanka
Ms. Hoang Thi Bich Hop Vietnam