increasing resilience of power generation to water ... · –can generate electricity…cannot...
TRANSCRIPT
Increasing Resilience of Power Generation to Water Shortages during Drought
Bridget Scanlon, Robert Reedy, Ian Duncan, Alex Sun, and Michael Young, and William F. Mullican
Bureau of Economic Geology, Jackson School of Geosciences
Differences between Energy and Water Systems
• Generation: – Can generate electricity…cannot generate
water
• Storage: – Can store water….cannot store electricity
• Transport: – Can transport electricity….cannot readily transport
water
• Out of phase behavior of water demand for electricity and water supply
Limited Connection between ERCOT and Other Grids
Basic Questions
• How much water does electricity generation use?
• What controls water requirements for electricity generation?
• How vulnerable are water sources for electricity generation to drought?
• How can we make the system more drought resilient?
Water Withdrawal
33%
18%
5%
41%
Kenny et al., 2009; USGS
Water Consumption (2010)
56%
27%
10% 4% 2% 2%
TWDB 2012 State Water Plan
Basic Questions
• How much water does electricity generation use?
• What controls water requirements for electricity generation?
• How vulnerable are these water sources?
• How can we make the system more drought resilient?
Controls on Water Usage by Power Plants
• Fuel type: nuclear fuel, coal, natural gas
• Generator type: steam turbine, gas turbine, combined cycle (steam + gas)
• Cooling system: open loop or once through, closed loop (recirculating ponds or cooling towers)
• Fuels often associated with generator types – TX Coal and nuclear plants…steam turbine
– TX natural gas…steam, gas, and combined cycle
Water Withdrawals by Fuel Type and Cooling System (2010 data)
Cooling Type
OT: once through; NG, natural gas
Water Withdrawal and Consumption by Fuel Type and Cooling System
Inverse relationship between water withdrawal and water consumption
Cooling Pond
Generator
Turbine
Condenser Heat Source
Boiler
Electricity
Boiler Water
System Boundary
Diversion (river or
lake)
Rainfall Evap.
Withdrawal
Discharge
Steam
Run-on
Recirculating Pond Steam Turbine
Large withdrawal Low consumption
Water Use by Generation Type
• Steam turbine • Gas turbine (~ 0.05 gal/kWh) • Combined cycle (gas and steam) • Cogeneration …. Combined heat and power
• Coal and nuclear plants in Texas….all steam
turbine • Natural gas…steam and gas turbines and
combined cycle (combined cycle water consumption = 1/3rd that of steam turbine)
Basic Questions
• How much water does electricity generation use?
• What controls water requirements for electricity generation?
• How vulnerable are water sources for electricity generation to drought?
• How can we make the system more drought resilient?
Power Plant Water Source
SW: 77% GW: 9% WW: 8% Muni: 5% Salt W: 1%
Consumption
30% Reduction in Per Capita Reservoir Storage since 1980s
Basic Questions
• How much water does electricity generation use?
• What controls water requirements for electricity generation?
• How vulnerable are water sources for electricity generation to drought?
• How can we make the system more drought resilient?
Reducing Drought Vulnerability
• Reduce demand for energy and water, increase supply of water, store more water
• Should we focus on withdrawals or consumption?
• How can we make power plants less water intensive?
• Could we use different sources of water?
• What about other ways of storing water besides surface reservoirs?
Water Withdrawal and Consumption by Fuel Type and Cooling System
Inverse relationship between water withdrawal and water consumption
How can we make power plants less water intensive?
• Water withdrawals: – Cooling towers – Dry cooling
• Water consumption: – Combined cycle natural gas – Gas turbines – Dry cooling
• Energy penalties and equivalent cost of water saved – Considerable energy penalties with dry cooling and
large capital costs
Conjunctive Use of Groundwater with Surface Water
Store Water in Aquifers
• Aquifer storage and recovery
• Store excess surface water in aquifers
• Allows adaptation to climate extremes…floods and droughts
• Power plants with take or pay contracts …. store unused water in aquifers
Basic Questions
• How much water does electricity generation use?
• What controls water requirements for electricity generation?
• How vulnerable are water sources for electricity generation to drought?
• How can we make the system more drought resilient?
Reservoir Storage
• $$ cost • Climate variability/change • Water availability SW GW FW salt water • Ecosystems fish • Energy demand • Fuel (availability Price) • Generator type • Cooling systems • Regulations • Time
Fuel Type
37
46
10
7.00.3
Coal
Natural Gas
Nuclear
Renewables
Other
TX
44
24
20
10
1.4
US
Methods
• Estimated water usage for 2010 using EIA, TWDB, and TCEQ data
• Evaluated controls on water usage: fuel, generator, cooling system
• Examined power plant water usage relative to reliability of water supplies (2011 drought)
• Future projections
-
10
20
30
40
50
60
70
80
90
< 0.1 0.1 - 0.5 0.5 - 1.0 1.0 - 2.5 2.5 - 5.0 5.0 - 21.1
Nu
mb
er o
f P
ow
er P
lan
ts
2010 Net Generation (Million MWh)
Biopower
Hydroelectric
Oil
NG
Nuclear
Coal
-
10
20
30
40
50
60
70
80
90
< 0.1 0.1 - 0.5 0.5 - 1.0 1.0 - 2.5 2.5 - 5.0 5.0 - 21.1
Nu
mb
er o
f P
ow
er P
lan
ts
2010 Net Generation (Million MWh)
ST
GT
CT/CA
IC
HY
-
5,000,000
10,000,000
15,000,000
20,000,000
25,000,000
30,000,000
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Month
ly n
et
genera
tion (
MW
h)
NG
Coal
Nuclear
Wind
Other
Water Usage for Power Plants 2010
• Consumption 3% of state water 0.5 maf 18 maf other consumers
• Withdrawals 22 maf
Drought
• Water
• T intake
• T discharge
Drought Proof
• Water quantity versus temperature issues • Dry cooling • Desalinate seawater • Gas turbines • Combined cycle • Cooling towers vs open loop systems • Wind solar • Conserve energy conserve water • Surface water groundwater conjunctive use • ASR Brackish water sea water • Retrofits new plants retirements
Generator
Turbine
Discharge Condenser Heat Source
Boiler
Electricity
Cooling Water
Warm Cooling Water
Steam
Boiler Water
System Boundary
Rainfall Evap.
River
Withdrawal
Once-Through Open-Loop Cooling Steam Turbine
Large withdrawal Low consumption
Generator
Turbine
Condenser Heat Source
Boiler
Electricity
Steam
Electricity Generation Using a Steam Turbine
Cooling Pond
Generator
Turbine
Condenser Heat Source
Boiler
Electricity
Boiler Water
System Boundary
Diversion (river or
lake)
Rainfall Evap.
Withdrawal
Discharge
Steam
Run-on
Recirculating Pond Steam Turbine
Large withdrawal Low consumption
Cooling Pond
Generator
Turbine
Condenser Heat Source
Boiler
Electricity
Boiler Water
System Boundary
Evap.
Diversion (river or
lake)
Discharge Withdrawal
Cooling Tower
Blowdown
Rainfall
Steam
Cooling Tower
Steam Turbine
Low withdrawal Higher consumption
Increasing Resilience of Power Generation to Water Shortages
during Drought
Bridget Scanlon, Robert Reedy, Ian Duncan, Alex Sun, and Michael Young, and William F.
Mullican
Bureau of Economic Geology, Jackson School of Geosciences, Univ. of Texas at Austin