-
Joint GCAM Community Modeling Meeting and GTSP Technical
Workshop Joint Global Change Research Institute College Park,
Maryland, USA
The Impact of Emissions Mitigation on Water Demand for
Electricity Generation PAGE KYLE, EVAN DAVIES, JAMES DOOLEY, STEVE
SMITH, MOHAMAD HEJAZI, JAE EDMONDS, AND LEON CLARKE
September 20, 2012
-
Motivation
! The electric sector accounts for about 40% of present-day
water withdrawals in the US, and is projected to grow substantially
in all regions over the next century ! Could be important for
resolving
basin-level water supplies and demands
! The water demands are dependent on the generation technology
! Contributes to uncertainty in the
magnitude of the future water draw from this sector
! Creates a natural link with the electricity system in
GCAM
Region
Total Industrial Withdrawals (km3/yr)
Electric Sector Withdrawals (km3/yr)
USA 220 207 Canada 31 28
Western Europe 110 96 Japan
16 5 Australia_NZ 3 6 Former
Soviet Union 79 66 China 133
72 Middle East 5 3 Africa
11 8 LaIn America 32 10
Southeast Asia 46 10 Eastern
Europe 30 23 Korea 3 2
India 35 31 Global total 753
568
-
A Brief Review of Cooling System Types
! Water is required at power plants for ! Re-condensing
steam from the boiler ! Boiler feed water make-up ! Flue gas
de-sulfurization ! Other uses
! Three basic methods of re-condensing steam, which differ in
the primary mechanism of heat displacement
System type
Mechanism of Heat
Displacement Cost ($/kW)
Withdrawal Intensity (m3/MWh)
ConsumpKon Intensity (m3/
MWh) Once-‐through flow
Increase in water temperature 19
150 1
EvaporaIve (recirculaIng)
EvaporaIon of water 28 4 2.5
Dry cooling Dissipated to air
182 0.3 0.3
-
Specific Coefficients Used
Technology Cooling system Water
Withdrawals Water ConsumpKon
Coal
1-‐thru 158 0.95 Evp 3.8 2.6
Pond 53.2 2.06
1-‐thru w/CCS 241 1.25 Evp w/
CCS 4.83 3.57
Oil / Natural gas 1-‐thru 152
0.91 Evp 4.55 3.13 Pond
4.55 3.13
Other Steam 1-‐thru 152 1.14 Evp
3.32 2.09 Pond 1.7 1.48
Nuclear 1-‐thru 193 1.02 Evp
4.17 2.54 Pond 30.7 2.31
Natural gas combined cycle
1-‐thru 49.5 0.38 Evp 0.96
0.75 Pond 25.9 0.91
1-‐thru w/CCS 62.5 0.66 Evp w/
CCS 1.88 1.43
IGCC
1-‐thru 147 0.13 Evp 1.48 1.41
1-‐thru w/CCS 186 0.41 Evp w/
CCS 2.22 2.04
Geothermal (convenKonal)
Evp 6.82 6.82 Hybrid/Dry 0.67
0.67
EGS Evp 18.1 18.1
Hybrid/Dry 3.2 3.2
CSP Evp 3.35 3.35
Hybrid/Dry 0.3 0.3 PV n/a 0.02
0.02
Wind n/a 0 0 Hydro n/a
0 17
! Cooling ponds function in similar fashion to once-through
flow OR evaporative cooling (depends on the specific plant
configuration)
! Hybrids generally function as dry cooling but use some
evaporative cooling (e.g. during times with high temperature)
-
Modeling the Electric Sector’s Water Demands in GCAM
! The current version of GCAM does not have water markets, so
there is no technology competition between the different cooling
system types
! For this reason, we assume the different shares of cooling
systems that will be deployed for each power plant type and each
region in future periods
Cooling system type
Region Power Plant Type Time
period Once-‐Through
Flow * Of which Saline
EvaporaKve Cooling Cooling Pond Dry
USA Coal Base year 39% 30%
48% 13% 0% USA Fossil,
non-‐coal Base year 59% 30%
24% 17% 0% USA Combined cycle
Base year 12% 30% 77% 2%
10% USA Nuclear Base year
38% 30% 44% 18% 0% USA
Geothermal Base year 0% 0% 60%
0% 40% USA IGCC/CCS Base
year n/a n/a n/a n/a n/a
USA CSP Base year n/a n/a
n/a n/a n/a USA Coal
Future periods 5% 5% 80% 10%
5% USA Fossil, non-‐coal Future
periods 5% 5% 80% 10% 5%
USA Combined cycle Future periods
5% 5% 33% 2% 60% USA
Nuclear Future periods 5% 5%
85% 10% 0% USA Geothermal
Future periods 0% 0% 60% 0%
40% USA IGCC/CCS Future periods
5% 5% 90% 0% 5%
-
Scenarios in this Analysis
Scenario Technology Strategy Climate
Policy NucCCS Nuclear and CCS
None RE Renewables None NucCCS_4.5
Nuclear and CCS 4.5 W/m2 RE_4.5
Renewables 4.5 W/m2 NucCCS_3.7
Nuclear and CCS 3.7 W/m2 RE_3.7
Renewables 3.7 W/m2
0
1
2
3
4
5
6
7
8
2000 2020 2040 2060 2080 2100
2120
W/m
2
NucCCS
RE
NucCCS_4.5
RE_4.5
NucCCS_3.7
RE_3.7
-
Global Electricity Generation by Scenario
0
100
200
300
400
500
2000 2020 2040 2060 2080 2100
EJ/yr
NucCCS NucCCS_4.5 NucCCS_3.7
RE RE_4.5 RE_3.7
0% 10% 20% 30% 40% 50% 60%
70% 80% 90%
100%
Developed Reforming Developing
! Five- to seven-fold expansion in all scenarios !
Developing economies account for greater than 70% of electricity by
the
end of the century ! By 2050, 85% of electricity is produced
at facilities that did not exist in
2005 ! Climate mitigation policy leads the electricity sector
to expand by up to
25%
-
Electricity Generation by Technology
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2005
2015
2025
2035
2045
2055
2065
2075
2085
2095
NucCCS
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2005
2010
2015
2020
2025
2030
2035
2040
2045
2050
2055
2060
2065
2070
2075
2080
2085
2090
2095
RE
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2005 2015 2025 2035 2045 2055
2065 2075 2085 2095
NucCCS_3.7
0%
10%
20%
30%
40%
50%
60%
70%
80%
90%
100%
2005 2015 2025 2035 2045 2055
2065 2075 2085 2095
RE_3.7
Hydro
Wind
PV
CSP
Geothermal
Nuclear
Biomass CCS
Biomass
Oil CCS
Oil
Gas CCS
Gas
Coal IGCC CCS
Coal IGCC
Coal
-
Water Withdrawals by Scenario
0
100
200
300
400
500
600
700
800
2000 2020 2040 2060 2080 2100
km3 /yr
Withdrawals
0
5
10
15
20
25
30
35
2000 2020 2040 2060 2080 2100
m
3 /MWh
Withdrawal Intensity
! Dramatic decline in withdrawal intensity in all scenarios as
older power plants are retired ! This change is consistent with
the trends of the last two decades based on
the available evidence ! RE scenarios generally have lower
water withdrawal intensity
NucCCS
NucCCS_4.5
NucCCS_3.7
RE
RE_4.5
RE_3.7
Hydro (all)
-
Water Consumption by Scenario
0
50
100
150
200
250
300
2000 2020 2040 2060 2080 2100
km3 /yr
ConsumpKon
0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
2000 2020 2040 2060 2080 2100
m
3 /MWh
ConsumpKon Intensity
! Switch from once-through flow to evaporative cooling amounts
to a shift from water withdrawals to water consumption ! The
consumption:withdrawal ratio is 0.05 in the base year ! In the
NucCCS scenarios, it increases to 0.20 ! In the RE scenario, it
increases to ~0.30 ! In the RE_policy scenarios, it increases to
~0.60≈
NucCCS
NucCCS_4.5
NucCCS_3.7
RE
RE_4.5
RE_3.7
Hydro (all)
-
Water Withdrawals by Technology
0
100
200
300
400
500
600
700
800
km^3/yr
NucCCS
0
100
200
300
400
500
600
700
800NucCCS_3.7
0
100
200
300
400
500
600
700
800
km^3/yr
RE
0
100
200
300
400
500
600
700
800RE_3.7
Hydro Wind PV CSP Geothermal
Nuclear Biomass CCS Biomass Oil
CCS Oil Gas CCS Gas Coal
IGCC CCS Coal IGCC Coal
-
Water Consumption by Technology
0
50
100
150
200
250
300
350
km^3/yr
NucCCS
0
50
100
150
200
250
300
350NucCCS_3.7
0
50
100
150
200
250
300
350
km^3/yr
RE
0
50
100
150
200
250
300
350RE_3.7
Hydro Wind PV CSP Geothermal
Nuclear Biomass CCS Biomass Oil
CCS Oil Gas CCS Gas Coal
IGCC CCS Coal IGCC Coal
-
Sensitivity Analysis - CCS Water Demands
! The potential range of CCS water demands is large. Switching
from a pulverized coal power plant without CCS to… ! PC with
post-combustion capture doubles the water demands ! IGCC or
oxy-fuel with CCS increases the water demands marginally ! IGCC
or oxy-fuel with CCS and using either dry cooling or
seawater-based
cooling reduces the water demands by 80% ! Switching from
evaporative cooling to dry cooling also increases costs and
decreases thermal efficiency
0
50
100
150
200
250
2000 2020 2040 2060 2080 2100
EJ/yr
Electricity GeneraKon
0 10 20 30 40 50 60 70
80 90 100
2000 2020 2040 2060 2080 2100
km3 /yr
Water ConsumpKon
NucCCS NucCCS_3.7
NucCCS_3.7_hi NucCCS_3.7_lo
-
Sensitivity Analysis – CSP Water Demands
0
50
100
150
200
250
2000 2020 2040 2060 2080 2100
EJ/yr
CSP Electricity
! CSP with thermal storage is very large in scenarios with
limited other options for producing baseload electricity
! The range in the water demand intensities depends on cooling
systems. Compared to the baseline scenarios here… ! Using only
evaporative cooling towers doubles the water demands ! Using only
dry/hybrid cooling systems reduces electricity generation by
30% (due to higher costs), and water demands by 85%
0
50
100
150
200
250
2000 2050 2100
km3 /yr
CSP Water ConsumpKon
RE RE_3.7 RE_3.7_hi RE_3.7_lo
-
Conclusions
! Water withdrawals in all scenarios investigated here remain
relatively flat for the next few decades ! Retirement of old
power plants with once-through flow systems ! New builds use
mostly evaporative cooling systems ! By 2050, 85% of the stock
did not exist in the model base year, so there is
a high degree of capital turnover ! Water consumption
increases in all scenarios
! Where the present-day electric sector only consumes
(evaporates) 5% of its water withdrawal, these scenarios describe
systems where this ratio is between 20% (NucCCS technology) and 60%
(RE technology with mitigation policy)
! Water should not be seen as an obstacle to CCS in the long
term ! For post-combustion capture (whether retrofits or new
builds), the water
demand increases from CCS are substantial ! However, in the
long run with known or expected carbon prices, the IGCC
and/or oxy-fuel plants would be the more relevant choices to
analyze ! Finally, the additional costs of dry cooling do not
increase the costs
prohibitively; this technology set remains valuable in
mitigation
-
Extra Slide: Characteristics of Technology Strategies
Technology strategy
Technology area NucCCS RE
Nuclear Power Capital and O&M
costs decline at 0.1% per year
Very high capital costs
($10,000 / kW)
Carbon Capture & Storage (CCS)
CCS not limited by availability
of CO2 storage reservoirs Small
storage capaciIes for
geologic CO2 storage
Solar Costs decline by 1%-‐2% per
year, 2005-‐2050 Costs decline by
2%-‐3% per
year, 2005-‐2050
Wind Costs decline by 0.25% per
year, 2005-‐2050 Costs decline by
0.5% per year,
2005-‐2050
Geothermal EGS not available EGS
available and cost-‐effecIve