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### DOE/NETL-400/2008/1339

September 30, 2008 

# Estimating Freshwater Needs to Meet Future Thermoelectric Generation Requirements
2008 Update

## Disclaimer

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of th eir employees, makes any warranty, express or implied, or assumes any lega l liability or responsibility for the accuracy, completeness, or usefulne ss of any information, apparatus, product, or process disclosed, or repres ents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trad e name, trademark, manufacturer, or otherwise does not necessarily co nstitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed therein do not necessarily state or reflect those of the United States Government or any agency thereof.

# Estimating Freshwater Needs to Meet Future Thermoelectric Generation Requirements
2008 Update



### DOE/NETL-400/2008/1339 September 30, 2008

NETL Contact:

Erik Shuster Office of Systems Analyses and Planning

National Energy Technology Laboratory www.netl.doe.gov

### Table of Contents

Executive Summary .......................................................................................................... 1 Introduction ....................................................................................................................... 8 Energy-Water Issues ...................................................................................................... 9 Water Availability ....................................................................................................... 9 NETL Energy-Water R&D Program .......................................................................... 10 Previous Water Needs Analysis ................................................................................... 11 Water Requirements for Thermoelectric Generation ................................................. 11 Projections of Thermoelectric Capacity and Generation ............................................ 14 Assumptions and Methodology ...................................................................................... 19 Step 1: Develop model plants ....................................................................................... 20 Fresh versus Saline Water ........................................................................................ 20 Step 2: Calculate water withdr awal and consumption factors ................................... 21 Evaporative Loss Associated with Once-Through Cooling Systems ........................ 21 Subcritical versus Supercritical Boiler for New Coal-Fired Power Plants ............. 21 Flue Gas Desulfurization Systems for Retrofit and New Coal-Fired Power Plants . 22 Integrated Gasification Combined Cycle Plants ...................................................... 22 Natural Gas Combined Cycle Plants ........................................................................ 22 Step 3: Quality Control and Model Validation ........................................................... 22 Step 4: Develop Future Cases ...................................................................................... 24 Step 5: Calculate regional w ithdrawal and consumption to 2030 ............................. 26 Water Use for CO 2 Capture Equipped Coal-Fired Power Plants .............................. 26 Results .............................................................................................................................. 2 8 Thermoelectric Generation – National Level Summary ............................................ 28 Thermoelectric Generation - National Level Results by Case ................................... 30 Thermoelectric Generation – Regional Results .......................................................... 40 Conventional Coal-Fired Generation - National Level Results by Case ................... 50 Conventional Coal-Fired Generation – Regional Results ......................................... 52 Carbon Capture Deployment Analysis ........................................................................ 58 Comparison of 2006 & 2007 Study Projections .......................................................... 63 Conclusions ...................................................................................................................... 66 Appendix A .................................................................................................................... A-1 Appendix B .................................................................................................................... B-1 Appendix C .................................................................................................................... C-1 Appendix D .................................................................................................................... D-1 Appendix E .....................................................................................................................E-1 Appendix F .....................................................................................................................F-1 Appendix G .................................................................................................................... G-1 References ...................................................................................................................... R-1Freshwater Needs for Thermoel ectric Generation, September 2008

1 

### Executive Summary Growing concerns about freshwater availabil ity must be reconciled with growing demand for power if the United States is to mainta in economic growth and current standards of living. Thermoelectric generating capacity is expected to increase by nearly 18% between 2005 and 2030, based on the Energy Information Administration’s (EIA) Annual Energy Outlook 2008 (AEO 2008) projections. 1 Previous water needs analyses have been conducted by the Department of Ener gy’s National Energy Technology Laboratory (DOE/NETL); one in 2004, 2006, and 2007. Th e 2004 report suggested that national freshwater withdrawals may increase slightly or decline depending on assumptions made, while freshwater consumption will likely increase dramatically. 2 However, regional water impacts can be significantly different th an national data averages might suggest. To characterize the significance of the re gional impacts on water use, the post 2004 reports compare regional electricity demand and capacity forecasts using corresponding AEO reports with representative water withdrawal and consumption estimates to identify regions where water issues could become acute.

This report is an update to the August 2007 report using proj ection from EIA’s AEO 2008 forecast. With increased “climate change” concerns and the possible future policies regarding carbon capture and sequestration (CCS), this report also examines the impact that CCS technologies would have on wate r withdrawal and consumption. Future freshwater withdrawal and consumption requirements for the U.S. thermoelectric generation sector were estimated for five cases, using AEO 2008 regional projections for capacity additions and retirements: a

Case 1 – Additions and retirements are propor tional to current water source and type of cooling system. Case 2 – All additions use fres hwater and wet recirculating cooling, while retirements are proportional to current water source and cooling system. Case 3 – 90% of additions use freshwater and wet recirculating cooling, and 10% of additions use saline water and once-through cool ing, while retirements are proportional to current water source and cooling system. Case 4 – 25% of additions us e dry cooling and 75% of addi tions use freshwater and wet recirculating cooling. Retirements are propor tional to current water source and cooling system. Case 5 – Additions use freshwater and wet recirculating cooling, while retirements are proportional to current water source and coo ling system. Five percent of existing freshwater once-through cooli ng capacity is retrofitted w ith wet recirculating cooling every five years starting in 2010.

Summary results for the five cas es, on a national basis, are pr esented in Table ES-1. For Cases 2 though 5, withdrawal is expected to decline, and c onsumption for all 5 cases is expected to increase. These results are consis tent with current and anticipated regulations and industry practice, which favor the use of freshwater recirculating cooling systems

a See Table 6 in the body of the report for a description of the rationale behind each of these cases and their assumptions.Freshwater Needs for Thermoel ectric Generation, September 2008

2 that have lower withdrawal requirements, but higher consumption requirements, than once-through cooling systems. Case 5 pr ovides the most extreme water consumption impacts. Converting a significant share of existing once-through fres hwater power plants to recirculating freshwater plants significan tly reduces water withdr awal, but significantly increases water consumption. Case 4 indicate s that dry cooling coul d have a significant impact on water consumption; compared to Cases 1-3, which have an average consumption of 5.0 BGD, Case 4 results in an almost 3.2% decline, equivalent to more than 57 billion gallons per year.

Table ES-1 - Thermoelectric Wat er Impacts, National Results Freshwater withdrawal or consumption (BGD) 2005 2010 2015 2020 2025 2030 Withdrawal 146.3 148.1 143.2 149.6 153.5 153.7 Case 1 Consumption 3.7 3.8 4.0 4.2 4.5 4.7 Withdrawal 146.3 146.3 139.4 140.1 140.3 139.0 Case 2 Consumption 3.7 3.9 4.0 4.4 4.8 5.1 Withdrawal 146.3 146.2 139.4 140.0 140.2 138.9 Case 3 Consumption 3.7 3.9 4.0 4.4 4.7 5.0 Withdrawal 146.3 146.1 139.1 139.6 139.5 138.1 Case 4 Consumption 3.7 3.8 4.0 4.3 4.5 4.8 Withdrawal 146.3 140.2 127.5 122.9 118.3 112.4 Case 5 Consumption 3.7 3.9 4.2 4.6 5.1 5.5

Each of the cases used different assumptions (see Table 6 for rationale behind each case and their assumptions). Due to the differences in assumptions, none of the cases can truly be considered a baseline for comparis on with other cases. However, the year 2005 can be used as a baseline against which to measure projected future withdrawal and consumption. As seen in the 2005 column of Table ES-1, the 2005 withdrawal and consumption values for each case are the same. Using this baseline, Table ES-2 was generated to show the percent change from th e 2005 baseline to each of the future years. The negative values in Table ES-2 for withdrawal indicate decreased withdrawal while the positive consumption values indi cate increasing consumption over time.

Table ES-2 – Percent Ch ange from 2005 Baseline, National Results Percent change from 2005 baseline 2010 2015 2020 2025 2030 Withdrawal 1.2 -2.1 2.3 4.9 5.0 Case 1 Consumption 4.5 7.5 14.8 21.6 28.4 Withdrawal -0.1 -4.7 -4.3 -4.1 -5.0 Case 2 Consumption 5.4 10.1 20.8 30.5 40.0 Withdrawal -0.1 -4.7 -4.3 -4.2 -5.1 Case 3 Consumption 5.1 9.4 19.2 27.8 36.5 Withdrawal -0.2 -4.9 -4.6 -4.7 -5.6 Case 4 Consumption 4.5 8.4 16.5 23.5 30.7 Withdrawal -4.2 -12.9 -16.0 -19.2 -23.2 Case 5 Consumption 7.1 13.8 26.4 37.8 48.9Freshwater Needs for Thermoel ectric Generation, September 2008

3 The regional component of the 2008 water ne eds analysis revealed some significant differences from the national averages. For ex ample, consider Case 2, which represents a plausible future cooling system scenario. The national percent changes in Table ES-2 indicate that water withdrawal will fall by 5% and that water consumption will rise by 40% between 2005 and 2030. As shown in Figu re ES-1 and Figure ES-2 on a regional basis, however, water withdrawal ranges fr om a 50% increase in the FRCC region to a 24% decline in ERCOT region; and while fr eshwater consumption increases in all regions, except in California, the biggest gains come in Florida (336%), New York (207%), and NPCC/NE (93%) region.

Figure ES-1 – Average Daily Regi onal Freshwater Withdrawal fo r Thermoelectric Power Generation – Case 2

-10

0 10 20 30 40 50

EC A

R
E RCOT MAAC M AI

N M A

PP

NP

C

C/

N Y

N

PCC / N

E FR C

C SERC SPP WECC / NWP P WECC/ R

M WECC/ C AWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

4 Figure ES-2 - Average Daily Regional Freshwater Consum ption for Thermoelectric Power Generation – Case 2

-0.5 0.0 0.5 1.0 1.5

ECA R ERCOT M AAC MAIN MAPP

N

PCC / NY

N

P CC/NE
F RCC SER C S PP WE

C

C/

N W

P P

W

E CC

/ RM

WECC/CAConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030

The regional results reflect recent U.S. popula tion shifts. Regions with strong population growth, such as the southeast and southwes t, generally exhibit high growth in water consumption requirements, while regions w ith minimal to mode st population growth, such as the Midwest and Mid-Atlantic, exhibit modest growth in water consumption requirements.

Specific to coal-fired gene ration, the analysis project s that by 2030, average daily national freshwater withdr awals may decrease to 76.7 BGD or increase to 103.6 BGD from a baseline level of 91.9 BGD, depending upon case assu mptions. The 2005 baseline coal-fired plant withdrawal represents 63% of the total thermoelectri c plant withdrawal. Average daily national freshwat er consumption resulting fr om U.S. coal-fired power generation could reach 3.3 B GD to 3.7 BGD from a base line level of 2.4 BGD, depending upon case assumptions. The 2005 ba seline coal-fired plant consumption represents 65% of the tota l thermoelectric plant consum ption. Case 2, coal-fired, regional water withdrawal and consumption ar e illustrated in Figures ES-3 and ES-4 respectively.Freshwater Needs for Thermoel ectric Generation, September 2008

5 Figure ES-3 – Average Daily Regional Freshwater Withdrawal for Coal-Fired Power Generation – Case 2

-5 0 5 10 15 20 25 30

E C

AR
E RC

O

T M A

AC M AIN MAPP

N

P CC/NY

N

PCC / N

E
F R

CC S E

RC S PP WECC/N W

P P WE

CC

/ R

M

W

ECC/CAWithdrawals (BGD)

Water Withdrawl, 2005 Incremental Water Withdraw, 2005 - 2030

Figure ES-4 - Average Daily Regional Freshwater Consumption for Coal-Fired Power Generation – Case 2

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ECAR ERCOT MAAC MAIN MAPP NPCC/NY

N

PC

C/

N

E FRCC SERC SPP

W

E CC/NW P P WEC C /R

M WEC C /C

AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030
This analysis and accompanying report were completed to estimate future freshwater needs both for coal-fired generation and for total thermoelectric generation. The resultsFreshwater Needs for Thermoel ectric Generation, September 2008

6 from this report will be used as a ba se forecast against which to compare accomplishments in freshwater withdrawal and consumption reductions. Additionally, report results will be used to better understand the regional impacts of constrained water

resources.
Carbon capture technologies could increase th e water demand of thermoelectric power plants. With increasing political and public interest regarding “climate change” and CO 2 mitigation, coupled with future water usage co ncerns, it is of intere st to estimate and explore the possi ble effects CO 2 mitigation will have on future water demands. This analysis assumes that carbon mitigation policies will be put in place in the near future that would require all new and existing PC pl ants with scrubbers and IGCC plants utilize carbon capture technologies by 2030. This an alysis follows the EIA AEO 2008 forecast and assumes the generation mix would not chan ge under such a climate control scenario. This analysis provides an upper boundary of the estimated additional water usage for carbon capture.

Four scenarios regarding the additional capac ity needed to make up for the “parasitic” power loss of the carbon capture retrofits we re evaluated. The 4 sc enarios were applied to the 5 cases. Scenario 1 only accounts fo r the increased water requirements for the carbon capture technologies used for the retr ofits and new builds with CCS and does not account for the 79.3 GW of reduced capacity due to the retrofits. Scenario 2 builds off of Scenario 1 and assumes that the additional capacity needed to make up for the parasitic loss of the retrofits are supplemented by 79.3 GW of new IGCC plants with recirculating cooling and include carbon capture technologies. Scenario 3 is similar to Scenario 2 except instead of IGCC plants making up the pa rasitic loss, supercritical PC plants are used. The fourth scenario assumes that the additional capacity needed to make up for the parasitic loss of the retrof its are supplemented by 79.3 GW of new nuclear plants with recirculating cooling. The projected results fo r PC plants with scrubbers and IGCC plants with 90% CO 2 capture for the year 2030 show an increase in water withdrawal and consumption. Figure ES-5 shows the additi onal amount of water withdrawal for each Case and Scenario if all forecasted PC plan ts with scrubbers and IGCC plants were to deploy carbon capture technologi es compared to no carbon ca pture deployment across all thermoelectric generation for the projected year 2030. For example, the bar for Case 2 in Figure ES-5 shows that in 2030, 139 BGD of water withdrawal is projected for all thermoelectric plants without carbon capture deployment. By deploying carbon capture technologies on the scrubbed coal-fired flee t and all new builds, an additional 3.6 BGD would be required under Scenario 1, resulting in a total of 142.6 BGD. If Scenario 2 is applied, 0.8 BGD would be added to Scenar io 1, resulting in a total of 143.4 BGD. Scenario 3 would add 2.1 BGD to Scenar io 1 resulting in a total of 144.7 BGD withdrawal. Scenario 4 would add approxi mately an additional 6 BGD to the 139 BGD non capture forecast, 3.6 BGD for the retr ofits and new builds and 2.5 BGD for the additional nuclear plants to make up for the capac ity lost due to the retrofitted coal plants.Freshwater Needs for Thermoel ectric Generation, September 2008

7 Figure ES-5 - Thermoelectric Generation with Ad ditional Water Withdraw al for PC and IGCC Carbon Capture Deployment for Year 2030

0 40 80 120 160Water Withdrawal(BGD)

12345

Case Scenario 4

Scenario 3

Scenario 2

Scenario 1

All Non-Capture Thermoelectric Plants

Figure ES-6 shows the additional amount of water consumption for each Case and Scenarios if all of the forecasted PC with scrubbers and IGCC plants were to deploy carbon capture technologies compared to all th ermoelectric plants w ithout carbon capture technologies. The bar for Case 2 in Figure ES-6 shows that in 2030, 5.1 BGD of water consumption is projected for all ther moelectric plants without carbon capture deployment. By deploying carbon capture tech nologies to the scrubbed coal-fired fleet and all new builds, an additional 2.5 BGD would be required under Scenario 1, resulting in a total of 7.6 BGD. If Scenario 2 is applied, 0.7 BGD would be added to Scenario 1, resulting in a total of 8.3 BGD. Scenario 3 would add 1.6 BGD to Scenario 1 resulting in a total water consumption of 9.2 BGD fo r Scenario 3. Scenario 4 would add approximately an additional 3.8 BGD to the 5.1 BGD non capture forecast, 2.5 BGD for the retrofits and new builds and 1.3 BGD for th e additional nuclear plants to make up for the capacity lost due to the retrofitted coal pl ants. Since recirculating cooling systems are used in three scenarios, additional wate r withdrawal is lower relative to water consumption.Freshwater Needs for Thermoel ectric Generation, September 2008

8 Figure ES-6 - Thermoelectric Generation with Ad ditional Water Consumption for PC and IGCC Carbon Capture Deployment for Year 2030

0 1 2 3 4 5 6 7 8 9 10Water Consumption(BGD)

12345
Case Scenario 3

Scenario 4

Scenario 2

Scenario 1

All Non-Capture Thermoelectric Plants



### Introduction The purpose of this report is to estimate future freshwater needs for thermoelectric power generation. Thermoelectric power plants – co al, oil, natural gas, and nuclear fueled power generators using a steam turbine based on the Rankine thermodynamic cycle – require significant quantities of wa ter for generating electrical energy. b For example, a 500 MW coal-fired power plant uses over 12 million gallons per hour of water for cooling steam turbine exhaust. 3,c The water required for thermoelectric plants is withdrawn primarily from large volume sources, such as lakes, rivers, oceans, and underground aquifers. While both freshwat er (approximately 70%) and saline water (approximately 30%) are currently used for th ermoelectric generation, this report focuses on freshwater because freshwater sour ces are becoming increasingly strained. 4 Water consumption is used to describe the lo ss of that water, typically through evaporation into the air. The United States Geological Surv ey (USGS) estimated that thermoelectric generation accounted for approximately 39% of freshwater withdrawals, ranking only slightly behind agricultural irrigation as the largest source of freshwater withdrawals in the United States in 2000. 4 However, the corresponding wa ter consumption associated with thermoelectric generation accounted for only 2.5% of total U.S. freshwater consumption in 1995. 5 As U.S. population and associated economic development continues to expand, the demand for electricit y will increase. The EIA’s latest forecast estimates U.S. thermoelectric generating cap acity will grow from approximately 700 GW in 2005 to 824 GW in 2030. 6 As such, thermoelectric power plants may increasingly

b Natural gas- and oil-fired combustion turbines are not sources of thermoelectric generation.

c Most of today’s power plants use water as the cooling medium and the amount of water required to condense the steam turbine exhaust is similar whether an open-loop or closed-loop cooling system is used depending on design conditions. Open-loop cooling systems continuously withdraw water from a local water source, and return the same quantity of water to the source. Closed-loop cooling systems circulate a similar total volume of water as open-loop systems for a given plant size, but only withdraw a limited amount of water to replace evaporative loss and blowdo wn. Additional informati on on power plant water requirements can be found in the Water Requirements for Thermoelectric Generation section of this report.Freshwater Needs for Thermoel ectric Generation, September 2008

9 compete for freshwater with other sectors such as domestic, commercial, agricultural, industrial, and in-stream use – particularly in regions of the country with limited freshwater supplies. In addition, current and future water-related environmental regulations and requirements will also challe nge the operation of existing power plants and the permitting of new thermoelectric generation projects.

Energy-Water Issues At the nexus of water and energy lies a wide variety of societal issues, policy and regulatory debate, environmental questions , technological challenges, and economic concerns. Water is emerging as a significant factor in economic development activities. Planning efforts must consider the availability and quality of water resources in a given locality or region to ensure that supplies ar e available to accommoda te existing and future water consumers over the long term. Failure to do so can result in stunted growth, economic flight, inequitable development, and even open conflict. In order for the power industry to be ecologically responsible, te chnologically ready, and economically stable, advanced research is imperative. Energy-wa ter issues have become increasingly visible in recent years, with a variety of concerns on the mind of industry, regulators, Congress, DOE, and the general public. A sampling of th ese issues includes the passing of the Energy Policy Act of 2005; repeated introduc tion of the Energy-Water Efficiency and Supply Technology Bill; increasingly severe regional drought condi tions across the country; additional difficulty siting new power generating facilities in arid regions; and further media attention and public concern over water availability and supply. The following is a brief summary of some of the t echnical, regulatory, and po litical issues that help explain the importance of water to thermoelectric generation. Additional background information on energy-water issu es is presented in Appendix A.

Water Availability Water shortages, potentially the greatest challe nge to face all sectors of the United States in the 21 st century, will be an especially difficult issue for thermoelectric generators due to the large amount of cooling water require d for power generation. According to a GAO 2003 report 7 , national water availability has not been comprehensively assessed in 25 years, thus water availabili ty on a national level is ultimately unknown. However, as the report goes on to say, current trends indica te that demands on the nation’s supplies are growing while the nation’s capacity to stor e surface-water is incr easingly more limited and ground-water is being depleted.

Water availability issues are intensified by the fact that popul ation increases are occurring in water-stressed areas. Figure 1 shows th e percent change in population by state from 1990 to 2000 and Figure 2 displays mean annual precipitation from 1890 to 2002. Comparison of the figures shows that areas wher e precipitation is low, especially in the southwest, are also areas of greatest population growth.Freshwater Needs for Thermoel ectric Generation, September 2008

10 Figure 1 - Percent Change in Population by State: 1990 to 2000 8

Figure 2 - Mean Annual Precipitation, 1890 to 2002 9 , 10

NETL Energy-Water R&D Program The U.S. Department of Energy, Office of Fossil Energy’s National Energy Technology Laboratory (DOE/NETL) is car rying out a comprehensive, integrated research and development (R&D) effort to enhance the e fficiency and environmental performance of the existing fleet of coal-fired power plan ts, which represent more than 300 gigawatts (GW) of generating capacity, and apply novel c oncepts to advanced power systems. The program goal is to ensure that technologies are available for deployment by 2015 that canFreshwater Needs for Thermoel ectric Generation, September 2008

11 reduce power plant freshwater withdrawal and consumption while minimizing the impacts of power plant operation on water quality. To achieve this goal, the energywater interface portion of the Innovations fo r Existing Plants (IEP) program conducts research in four areas: Non-Traditional Sources of Process and Cooling Water; Innovative Water Reuse and Recovery; Adva nced Cooling Technology; and Advanced Water Treatment and Detection Technology. The portfolio of energy-water nexus technology R&D projects enco mpasses laboratory studies, m odeling, and pre-commercial demonstration full-scale testing. Project suc cess is intimately tied to key collaborations and partnerships with industry, federal, st ate, and local agencies, and the academic and research communities. This water needs analysis was conducted in support of the IEP energy-water R&D activity.

Previous Water Needs Analysis In 2004, NETL conducted a similar water needs analysis to estimate how thermoelectric power plants will impact national freshwater resources through 2025. 2 Using the EIA 2004 Annual Energy Outlook’s (AEO) reference cas e forecast for electricity generating capacity, future freshwater requirements for both total and coal-based thermoelectric generation were estimated and compared to current and past water use by the power sector. In 2006, NETL develo ped a new water analysis which used a different methodology and different cases. The co mparisons of the 2004 and 2006 studies are described in more detail in the August 2006 Estimating Freshwater Needs to Meet Future Thermoelectric Generation Requirements study. All post 2004 wate r analyses utilize the same methodology as the August 2006 repor t and use corresponding EIA AEO data.

Water Requirements for Thermoelectric Generation A significant quantity of water is required fo r thermoelectric power plants to support electricity generation. The la rgest demand for water in ther moelectric plants is cooling water for condensing steam. Thermoelectric generation relies on a fu el source (fossil, nuclear, or biomass) to heat water to steam that is used to drive a turbine-generator. Steam exhausted from the turbine is conden sed and recycled to a steam generator or boiler. The steam condensation typically o ccurs in a shell-and- tube heat exchanger known as a condenser. The stea m is condensed on the shell si de by the flow of cooling water through tube bundles loca ted within the condenser. Cooling water mass flow rates of greater than 50 times th e steam mass flow rate are necessary depending on the allowable temperature rise of the cooling water – typically 15-25 oF. The design and operating parameters of the cooling system are critically important to overall power generation efficiency. At higher condenser cooling water inlet temperatures, the steam condensate temperature is higher and subsequen tly turbine backpressu re is higher. The turbine backpressure is invers ely related to power generati on efficiency: the higher the turbine backpressure, the lower the power generation efficiency.

There are three general types of cooling system designs used for thermoelectric power plants: once-through, wet recirculating, and dr y. In once-through systems, the cooling water is withdrawn from a local body of wate r such as a lake, river, or ocean and the warm cooling water is subsequently discharg ed back to the same water body after passingFreshwater Needs for Thermoel ectric Generation, September 2008

12 through the surface condenser. As a result, plants equipped with once-through cooling water systems have relatively high water withdrawal, but low water consumption.

There are two primary technologies used to support wet recirculating cooling systems – wet cooling towers and cooling ponds. The mo st common type of recirculating system uses wet cooling towers to dissipate the heat from the cooling water to the atmosphere (Figure 3). In wet recirculating systems, warm cooling water is pumped from the steam condenser to a cooling tower. The heat from the warm water is tran sferred to ambient air flowing through the cooling tower. In th e process, a portion of the warm water evaporates from the cooling tower and forms a water vapor plume. The cooled water is then recycled back to the condenser. B ecause of evaporative losses, a portion of the cooling water needs to be discharged from the system – known as blowdown

− to prevent the buildup of minerals a nd sediment in the water th at could adversely affect performance. The quantity of blowdown require d for a particular cooling water system is determined by a parameter known as “cycles of concentration”, which is defined as the ratio of dissolved solids in the circulating water to that in the makeup water. As the cycles of concentration increases, the quantit y of blowdown and make up water decreases. For a wet recirculating system , only makeup water needs to be withdrawn from the local water body to replace water lost through evapor ation and blowdown. As a result, plants equipped with wet recirculating systems have relatively low water withdrawal, but high water consumption, compared to once-thro ugh systems. Wet cooling towers are available in two basic designs – mechanical draft and natural draf t. Mechanical draft towers utilize a fan to move ambient air through the tower, wh ile natural draft towers rely on the difference in air density between the wa rm air in the tower and the cooler ambient air outside the tower to draw the air up through the tower. In both designs, the warm cooling water is discharged into the tower fo r direct contact with the ambient air. A cooling pond serves the same purpose as a wet cooling tower, but relies on natural conduction/convection heat transfer from th e water to the atmosphere as well as evaporation to cool th e recirculating water.

Dry cooling systems can use either a direct or indirect air coo ling process. In direct dry cooling, the turbine exhaust steam flows thr ough tubes of an air-cooled condenser (ACC) where the steam is cooled directly via conductiv e heat transfer using a high flow rate of ambient air that is blown by fans across the outside surface of the tubes. Therefore, cooling water is not used in the direct air- cooled system. For indirect dry cooling, a conventional water-cooled surface condenser is used to condense the turbine exhaust steam, but a dry cooling tower, similar in design to an A CC, is used to conductively transfer the heat from the wate r to the ambient air. As a result, there is no evaporative loss of cooling water with an indirect dry cooling system and both water withdrawal and consumption are minimal.Freshwater Needs for Thermoel ectric Generation, September 2008

13 Figure 3 - Wet Recirculating Cooling Wat er System for a 520-MW Coal-Fired Boiler

In the United States, existing thermoelectri c power plants use each of these types of systems, with estimates indicating that 42.7% of generating cap acity is once-through, 41.9% wet recirculating, 0.9% dr y cooling, and 14.5% cooling ponds. 11 Table 1 presents a summary of the current percentage dist ribution of cooling t echnology by generation type. It should be noted that the data for combined cycle plants represents only about 7% of the total combined cycle pl ants currently in operation. Th is is because not all plants provided cooling data, so the table was created using information available at the time. If all plants reported cooling data , it is most likely that dry co oling would repr esent a much smaller percentage of the total combined cycl e cooling. Figure 4 illustrates the location of water dependent cooling systems used for thermoelectric power generation by technology type and water source 12

.
Table 1 - Cooling Technology by Generation Type Percentage (%) Generation Type Wet Recirculating OnceThrough Dry Cooling Pond Coal 48.0% 39.1% 0.2% 12.7%Fossil NonCoal 23.8% 59.2% 0.0% 17.1% Combined Cycle 30.8% 8.6% 59.0% 1.7% Nuclear 43.6% 38.1% 0.0% 18.3% Total 41.9% 42.7% 0.9% 14.5% 3,804,950 lb/hr

Boiler Feedwater Steam

Condensate Warm Water

Cool Water Steam Condenser Evaporation & Drift

Blowdown Water Make-up Water 5,188 gpm 1,297 gpm 25 o F Rise 187,600 gpm 520 MW 3,891 gpm

7,645 gpm Generator Turbine

Cooling Tower BoilerFreshwater Needs for Thermoel ectric Generation, September 2008

14 Historically, the choice of cooling technol ogy for a particular plant depended on the quantity and quality of local water sour ces coupled with co st and performance characteristics of the different systems. The use of closed-loop systems, however, is likely to become much more pronounced in th e future due to the Clean Water Act 316(b) provisions and public pressures. d Although once-through cooling systems can still be legally permitted under 316(b), the complexity of the permitting, analysis and reporting requirements may discourage their use.

Figure 4- Cooling Systems by Technology and Water Source



### Projections of Thermoelectri c Capacity and Generation The EIA publishes its Annual Energy Outlook (AEO) to provide a forecast as to where the energy sector will be in the future, incl uding projections of ther moelectric capacity and generation. The AEO projections ar e based on EIA’s Nati onal Energy Modeling System (NEMS), which is revised yearly to reflect technology advances, supply and demand adjustments, and other market forc es. AEO 2008 projecti ons of capacity and generation to 2030 are used in this analysis to calculate future thermoelectric generation water withdrawal and consumption. Table 2 summarizes projecte d changes in U.S.

d See Appendix A for more details on CWA 316(b).

Water Type

Cooling TypeFreshwater Needs for Thermoel ectric Generation, September 2008

15 electric power generating capacity from 2005 to 2030. Coal-fired generating capacity, including IGCC, is projected to increase by 96 GW from 2005 to 2030.

Table 2 - AEO 2008 Thermoelectric Capa city Projections – 2005 to 2030 2005 2010 2015 2020 2025 2030 Net Generating Capacity Coal Steam 310 316 324 343 372 406
Other Fossil Steam 121 118 94 93 93 93 Combined Cycle 169 190 192 197 206 210
Nuclear 100 101 102 111 116 115 Total Thermoelectric 700 725 712 744 787 824
Cumulative Additions (Planned and Unplanned) - 2005 Baseline Coal Steam 0 8 18 37 66 100
Other Fossil Steam 0 0 0 0 0 0 Combined Cycle 0 13 16 20 29 33
Nuclear 0 0 0 8 13 17 Total Thermoelectric 0 21 33 65 108 150

Cumulative Retirements - 2005 Baseline Coal Steam 0 2 3 4 4 4 Other Fossil Steam 0 1 26 26 27 27 Combined Cycle 0 0 0 0 0 0 Nuclear 0 0 0 0 0 4 Total Thermoelectric 0 3 30 30 31 35Freshwater Needs for Thermoel ectric Generation, September 2008

16 AEO 2008 also includes a breakout of thermo electric capacity and generation by region using boundaries similar to the former 13 No rth American Electric Reliability Council (NERC) control regions, excluding Alaska and Hawaii. This analysis presents the regional data according to the former NERC regions because the data from AEO 2008 uses those regions. These NERC regions are sh own in Figure 5 and a description of the regional abbreviations is provided in Table 3.

Figure 5 - NERC Regions

Table 3 – Description of NERC Regions Region Number Abbreviation Region

1 ECAR East Central Area Reliability Coordination Agreement 2 ERCOT Electric Reliability Council of Texas 3 MAAC Mid-Atlantic Area Council 4 MAIN Mid-America Interconnected Network 5 MAPP Mid-Continent Area Power Pool 6 NPCC/NY Northeast Power Coordinating Council/New York 7 NPCC/NE Northeast Power Coordinating Council/New England 8 FRCC Florida Reliability Coordinating Council 9 SERC Southeastern Electric Reliability Council 10 SPP Southwest Power Pool 11 WECC/NWPP Western Electricity C oordinating Council/Northwest Power Pool 12 WECC/RM Western Electricity Coordinating Council/Rocky Mountains, AZ, NM, southern NV 13 WECC/CA Western Electricity Coordinating Council/California WECC/ NWPP MAPP MAIN

ECAR NPCC/ NY

NPCC/ NE

MACC

FRCC
SPP ERCOT WECC/

RM WECC/ CA SERCFreshwater Needs for Thermoel ectric Generation, September 2008

17 Figure 6 and Figure 7 show that thermoelect ric capacity (GW) a nd generation (billion kWh) will increase in most of the NERC re gions by 2030, reflecting required generation to meet anticipated demand growth. Both ca pacity and generation growth are presented because the two are not necessarily direct ly linked. For example, if under-utilized capacity exists in a regio n, generation can increase w ithout a change to capacity.

Figure 6 - Thermoelectric Capacity, 2005 vs. 2030, by NERC region

0 20 40 60 80 100 120 140 160 180 200

E

CAR

E

RCO T M

AAC MAIN M

APP

NPCC/NY NPCC/N E

FRCC SER C SPP

WECC / NWPP WE CC /R

M

W

EC C/

C

ACapacity (GW)

Thermoelectric Capacity, 2005 Incremental Thermoelectric Capacity, 2005-2030

Figure 8 and Figure 9 present the same in formation for the portion of the total thermoelectric capacity and generation that co rrespond to coal-fired plants. Coal-fired capacity and generation will also increas e in most of the NERC regions by 2030. Regions with greater then 50% increase in incremental capacityFreshwater Needs for Thermoel ectric Generation, September 2008

18 Figure 7 - Thermoelectric Generation, 2005 vs. 2030, by NERC region

0 200 400 600 800 1000 1200

ECAR ERCOT MAAC MAIN M

AP P

N

PCC / N

Y

N

PCC / N

E

F

R

C

C

SERC SPP WEC C/NWPP

W

ECC/RM

W

EC C

/CAGerneration (billion kWh)

Thermoelectric Generation, 2005 Incremental Thermoelectric Generation, 2005-2030

Figure 8 – Coal-Fired Capacity, 2005 vs. 2030, by NERC region

-10

10 30 50 70 90 110

EC A

R ERCO T MAA C M AIN MAP P NPC C

/NY

N

P

CC/N E

FRCC SE R

C S PP

W

E

CC/N W

PP WE C

C/RM

WECC/CACapacity (GW)

Coal-Fired Capacity, 2005 Incremental Coal-Fired Capacity, 2005-2030 Regions with greater then 100% increase in incremental coal-fired capacityFreshwater Needs for Thermoel ectric Generation, September 2008

19 Figure 9 – Coal-Fired Generation, 2005 vs. 2030, by NERC region

-100 0 100 200 300 400 500 600 700 800

ECAR ERCOT MAA C MAIN MAP P

N

PC C/N Y NP CC/ NE FRCC SERC SPP

W

EC C/

NW P

P WE CC /RM

W

E

CC/CAGerneration (billion kWh)

Coal-Fired Generation, 2005 Incremental Coal-Fired Generation, 2005-2030



### Assumptions and Methodology Using the electricity capacity and genera tion forecasts provided by AEO 2008 and the water use estimates provided by EIA-767, an estimate of freshwater consumption and withdrawal was obtained for the U.S. ther moelectric power generation industry through 2030. Table 4 lists the resources used fo r this analysis, and summarizes how each resource supported the analysis.

These sources provided data from which wa ter withdrawal and consumption factors (water-use scaling factors) could be calcula ted for a given category of power plant in a given region. The water use scaling factors in dicate average rate of water use per unit of electrical output – gallons pe r hour per kilowatt (gal/kWh).

Figure 10 provides a flowchart depiction of the methodology used to conduct the analysis. A brief description of each step in the process is presented below. A more detailed discussion of the methodol ogy is provided in Appendix B.Freshwater Needs for Thermoel ectric Generation, September 2008

20 Table 4 – Data Resources Resource Type of Data EIA Annual Energy Outlook (AEO) • Projections of capacity and generation by NERC region for coal, non-coal fossil, and nuclear plants

• Coal capacity, generation, and capacity factor

breakdown by four categories: existing unscrubbed, existing scrubbed, new PC (scrubbed), and IGCC NETL 2005 Coal Power Plant Database – Including data from 2003 EIA-767 • Plant generation

• Average water withdrawal and consumption

• Cooling water source

• Type of cooling water system

• Type of boiler

• Type of FGD system EIA-860 • Plant location by NERC region

• Plant summer capacity CMU/NETL – Integrated Environmental Control Model (IECM) • Water use factors for wet FGD and dry FGD

Power Plant Water Consumption Study, August 2005 – DOE/NETL • Water use factors for boiler make-up

Cost and Performance Comparison Baseline for Fossil Energy Power Plants, Volume 1: Bituminous Coal and Natural Gas to Electricity. April 2007, DOE/NETL. • Water use factors for IGCC plants

• Water use for PC and IGCC plants employing

carbon capture technologies

Figure 10 - Methodology for the 2006 Water Needs Analysis

Develop model plants to represent existingthermoelectric fleet Calculate water withdrawal and consumption factors Quality control and model validation Develop future cases to evaluate Calculate regional withdrawal and consumption to 2030 Step 1 Step 2 Step 3 Step 4 Step 5

Step 1: Develop model plants To obtain the resolution desired for this analysis, water withdrawal and consumption factors were determined for a large number of plant configurati ons, based on location, generation type, cooling water source, cooli ng system type, and where applicable, boiler type and type of FGD system. The existi ng thermoelectric fleet was segregated into numerous configurations, called “model plants” using data contained in several sources: the NETL Coal Plant Database, EIA-767, and EIA-860.

Fresh versus Saline Water The analysis focuses on freshwater impacts asso ciated with future thermoelectric power plants. It is recognized that saline water is used at a number of power plants in oncethrough cooling systems. However, in light of 316(b) regulations for new facilities thatFreshwater Needs for Thermoel ectric Generation, September 2008

21 favor recirculating systems and siting difficu lties for coastal-based power plants, the percentage of saline-based cooling systems at new plants is expected to be relatively small. Furthermore, no distinction is made between surface and groundwater; both are included as freshwater.

Step 2: Calculate water withdr awal and consumption factors For each model plant defined in Step 1, water withdrawal and consumption factors were calculated using the data sources outlined above. For coal-fired plants, the water withdrawal and consumption factors were based on the sum of three components: 1) boiler make-up water; 2) FGD make-up wate r; and 3) cooling wa ter. Average water withdrawal (gal/hr), average water consump tion (gal/hr), and summer capacity were used to calculate average withdrawal and cons umption scaling factors (gal/kWh) for each model plant in each of the NERC regions. Nu clear, oil steam, gas steam, and natural gas combined-cycle plants were classified ac cording to NERC region, cooling water source (fresh or saline), and cooli ng water system (recirculating or once-through). A summary of the regional water withdrawal and consump tion factors used in the analysis is included in Appendix D.

The following is a brief discussion of the more important assumptions made in calculating the water use factors.

Evaporative Loss Associated with Once-Through Cooling Systems One important point needs to be made rega rding consumption levels for once-through cooling systems. Although once-through consum ption levels are extremely small at the plant boundaries, downstream consumption (eva poration) due to the elevated discharge temperature is not insignificant. An Elect ric Power Research Institute (EPRI) study estimated that once-through consumpti on levels, when including downstream evaporation, are less than, but of the same magnitude as, wet recirculating cooling system consumption levels. 13 EPRI estimated once-through fossil plant water consumption levels of 300 gal/MWh versus closed-loop water consumption levels of 480 gal/MWh. For nuclear plants, the corresponding num bers are 400 gal/MWh and 720 gal/MWh. However, since this analysis relies on th e water withdrawal and consumption data reported by power plants to EIA, it does not account for this downstream evaporative loss.

Subcritical versus Supercritical Boiler for New Coal-Fired Power Plants The analysis uses different water use scaling factors for coal-fired power plants based on boiler type. A supercritical boiler is more efficient and therefore requires less cooling water flow than a subcritical boiler for an equivalent amount of electrical generation output. Future coal-fired plant capacity is assumed to be split as 75 supercritical and 25 subcritical for the water analysis. Appendix C provi des additional background information and justifica tion for this assumption.Freshwater Needs for Thermoel ectric Generation, September 2008

22 Flue Gas Desulfurization Systems for Retrofit and New Coal-Fired Power Plants The FGD make-up water requirement depends on the type of FGD system – either wet or dry. Dry FGD systems require much less water than wet FGD systems, for example, so different factors were used. The FGD make-up water factors were calculated using material balance data contained in Ca rnegie Mellon University’s Integrated Environmental Control Model (IECM). 14 The amount of existing non-scrubbed capacity projected to be retr ofit with FGD was obtained from EIA based on AEO2007 data. It was further assumed that all new coal-fired plants would be equipped with FGD. Since emission regulations do not dictate technol ogy selection, the anal ysis apportions FGD type to retrofit and new capacity additions ba sed on the existing split in the coal-fired power fleet (by summer capacity), which is 90% wet/10% dry.

Integrated Gasification Combined Cycle Plants Water requirements for integrated gasification combined cycle (IGCC) plants were obtained from a baseline study conducted by DOE/NETL in 2007. 16 The average withdrawal and consumption estimates of th ree IGCC processes in the study were used for this analysis. The water requirements for IGCC facilities differ from those at pulverized coal facilities. While both require cooling water, IGCC requires substantially less since a large fraction of the output fr om an IGCC plant is produced from the combustion turbines, which require minimal water. Moreover, since IGCC relies on water for significant process (non-cooling) use, it is unlikely that a saline water source would be desirable. The model IGCC coal plant, therefore, is restricted to freshwater use.

Natural Gas Combined Cycle Plants In calculating water withdrawal and consump tion quantities for combined-cycle plants, an adjustment was made to account for the f act that the gas turbine portion of the plant does not require cooling water. The design capacity of the gas turbine portion of a combined-cycle facility is typically twice that of the steam turbine portion; in other words, two-thirds of a combined-cycle plant’s total output is derived from the gas turbine(s). Therefore, only about one-third of the plan t output is used for steam generation, with its associated water requireme nts. For this analysis, water withdrawal and consumption factors were applied to only one-third of the combined-cycle capacity. Appendix E provides additional background in formation and justification for this assumption.

Step 3: Quality Control and Model Validation Step 3 represents efforts desi gned to ensure quality control for the analysis. The water withdrawal and consumption factors that were used in the model were obtained through a rigorous statistical evaluation of data from EI A. SPSS statistical software was utilized to generate boxplots of da ta that were used to identify outliers. These outliers were not considered during the calculation of water wi thdrawal and consumption factors. The following is a detailed description of the process used to identify outliers.Freshwater Needs for Thermoel ectric Generation, September 2008

23 For each coal, fossil non-coal, and nuclear plant identified in EIA-767, a withdrawal usage factor (gal/MWh) was calculated. The plants were then segregated into the following groups by fuel, cooling system type , and boiler type (where applicable):

• Coal Recirculating Subcritical

• Coal Recirculati ng Supercritical

• Coal Once-Through Subcritical

• Coal Once-Through Supercritical

• Coal Cooling Pond Subcritical

• Coal Cooling Pond Supercritical

• Fossil Non-Coal Recirculating

• Fossil Non-Coal Once-Through

• Fossil Non-Coal Cooling Pond

• Nuclear Recirculating

• Nuclear Once-Through

For once-through and cooling pond plants, with drawal usage factors were multiplied by the corresponding cooling system design temp erature rise to norma lize the data. For recirculating plants, this step was not taken since the temperature rise would affect the size of the cooling tower, but not the amount of evapora tive loss or blowdown that determine the make-up withdrawal rate.

The appropriate data (gal/MWh for recirculating plants and gal/MWh x Δ T for oncethrough plants) for the above categories was coll ected and inserted in to SPSS to generate boxplots of the data in each of the above categories to identify outliers. An outlier is a data point "far away" from the rest of the data. Some of the water usage data points calculated from the EIA databases were furt her away from the general data population than what seems reasonable. The outliers ca n indicate faulty data entry, or possibly unusual operation conditions. For purposes of calculating the re gional water usage factors for this study, it was decided to identi fy and eliminate the st atistically significant outliers using the box plot technique described below.

Boxplots are a graphical tool used to identify the center, spread, exte nt and nature of any departure from symmetry, and outliers contained in a data set. To construct such a plot, data must be ordered in value from smallest to largest. The lower fourth and upper fourth of the data can then be identified. The lowe r fourth is the median of the smallest n/2 observations when n is even, and the median of the smallest (n+1)/2 observations when n is odd. The upper fourth is the median of the largest n/2 observations when n is even, and the median of the largest (n+1)/2 observati ons when n is odd. The fourth spread, f s , is the difference between the upper and lower fourths. Any observation farther than 1.5f s from the closest fourth is a mild outlier while those observations farther than 3f s from the closest fourth are extreme outliers 26

. Figure 11 provides an example of a typical boxpl ot. In this plot, th e upper edge of the box represents the upper fourth, while the lowe r edge represents the lower fourth. TheFreshwater Needs for Thermoel ectric Generation, September 2008

24 horizontal line passing thr ough the box indicates the median value of the data. The circles above and below the box indicate outlie rs while the vertical lines extending above and below the box represent the highest and lo west observations not considered outliers.

Figure 11 – Example Boxplot 27

Outliers identified by SPSS boxplots were elimin ated from the calculation of water usage factors. Table 5 presents th e number of data points availa ble as well as the number of outliers identified in each of the 11 categories considered.

Table 5 – Data Points and Outli er Totals for QA/QC Categories Category Data Points Available Outliers Eliminated Coal Recirculating Subcritical 199 51 Coal Recirculating Supercritical 46 7 Coal Once-Through Subcritical 400 71 Coal Once-Through Supercritical 40 3

Coal Cooling Pond Subcritical 62 0 Coal Cooling Pond Supercritical 9 4 Fossil Non-Coal Recirculating 88 34 Fossil Non-Coal Once-Through 289 55 Fossil Non-Coal Cooling Pond 6 0 Nuclear Recirculating 39 7 Nuclear Once-Through 55 9

Appendix F presents SPSS boxplots generated fr om the original data for each of the above categories as well as boxplots generate d after outliers were eliminated from the data set.

Step 4: Develop Future Cases Future water withdrawal and consumption fo r the U.S. thermoelectric generation sector are estimated for five cases – one reflecti ng status quo conditions, two reflecting varyingFreshwater Needs for Thermoel ectric Generation, September 2008

25 levels of regulations regarding cooling wate r source, one incorpora ting dry cooling, and one reflecting regulatory pressures to c onvert existing once- through capacity to recirculating capacity. Table 6 presents the description and rationale for the five selected

cases.

Table 6 – Case Descriptions for the Water Needs Analysis Case Description Rationale Case 1: Additions and retirements proportional to current water source and type of cooling system. Status quo scenario case. Assu mes additions and retirements follow current trends.

Case 2: All additions use freshwater and wet recirculating cooling, while retirements are proportional to current water source and cooling system. Regulatory-driven case. Assumes 316(b) and future regulations dictate the use of recirculatin g systems for all new capacity. Retirement decisions hinge on age and operational costs rather than water source and type of cooling system.

Case 3: 90% of additions use freshwater and wet recirculating cooling, and 10% of additions use saline water and once-through cooling, while retirements are proportional to current water source and cooling system. Regulatory-light case. New additions favor the use of freshwater recirculating systems, but some saline capacity is permitted. Retirement decisions remain tied to age and operational costs, tracking current source withdrawals.

Case 4: 25% of additions use dry cooling and 75% of additions use freshwater and wet recirculating cooling. Retirements are proportional to current water source and cooling system. Dry cooling case. Regulatory an d public pressures result in significant market penetration of dry cooling technology. Retirement decisions remain tied to age and operational costs, tracking current source withdrawals.

Case 5: Additions use freshwater and wet recirculating cooling, while retirements are proportional to current water source and cooling system. 5% of existing freshwater once-through cooling capacity retrofitted with wet recirculating cooling every 5 years starting in 2010. Conversion case. Same as Case 2, except regulatory and public pressures compel state agencies to dictate the conversion of a significant amount of existing freshwater once-through cooling systems to wet recirculating.

The five cases were selected to cover the range of possible design choices for new power plants including the source of water (fresh or saline) and t ype of cooling system (wet recirculating or dry). In addition, Case 5 a ssumes that 25% of exis ting power plants with a once-through cooling system are retrofit with a wet recirculating system. For all five cases, it is assumed that plant retirements o ccur proportional to current water source and cooling system type.Freshwater Needs for Thermoel ectric Generation, September 2008

26 Step 5: Calculate regional w ithdrawal and consumption to 2030 Step 5 integrates the water withdrawal and c onsumption factors calculated in Step 2 with the various cases defined in Step 4 to a ssess the regional and national impacts on water withdrawal and consum ption out to 2030. The Annual Energy Outlook provides projections of future electri city generating capacity by year , by generation type and by NERC region. Apportioning this capacity among the chosen model plants for a given case and then applying the water withdraw al and consumption factors enabled the calculation of estimated water withdrawal a nd consumption trends for each of the five future cases.

Water Use for CO 2 Capture Equipped Coal-Fired Power Plants Carbon capture technologies could increase the water demand on thermoelectric power plants. With increasing political and public interest regarding “climate change” and CO 2 mitigation, coupled with future water usage co ncerns, it is of intere st to estimate and explore the possible effects CO 2 mitigation will have on fu ture water demands. EIA forecasts a 31% increase in coal -fired generation by the year 2030 1 . Current carbon capture technologies under development for coal-based power generation require large amounts of water. This analysis assumes th at aggressive carbon m itigation policies will be put in place in the near future that woul d require all new and ex isting PC plants with scrubbers and IGCC plants to utilize carbon capture technol ogies by 2030. The deployed carbon capture technologies used in this analysis remove a nominal 90% of the CO 2 that would be generated from the fuel carbon. Ca rbon capture technologies are applied in the year 2020. The analysis follows the EIA AE O 2008 forecast and assumes the generation mix would not change under such a climate control scenario. This analysis provides an upper boundary of the estimated additional water usage for ca rbon capture. Decisions to retrofit existing plants are co mplicated and involve many factor s such as plant age, plant size, capacity, economic viabili ty, land restraints, and loca tion to carbon sink and are outside of the scope of this work.

AEO 2008 projects that in th e year 2030, 73 MW of power wi ll be generated from PC plants that do not have scrubbers for sulfur control. Therefore, this analysis does not include those plants for CO 2 capture. It is assumed that the PC plants without scrubbers are the oldest plants and that it is not feasible to retrofit them with CO 2 capture technologies. Therefore these plants would be subjected to carbon trading.

The carbon capture section of this analysis uses a 1 st order approach derived from a recent NETL study of the cost and perfor mance impacts associated with CCS technologies on coal-based power plants. 16 Water consumption and withdrawal factors, gallons used per energy genera ted on a net generation basis, from the detailed study were developed for the subcritical and supercriti cal plants. The wate r use for the carbon capture ready IGCC plants was the average of the three gasificati on technologies studied in the detailed report since the types of gasifiers used are notknown for future generation. The water requirements, at full load, for PC and IGCC plants with and without carbon capture derived from the detail performance st udy and used in this an alysis is shown in Figure 12. All additional cooling systems re quired for the retrofits and all new PC andFreshwater Needs for Thermoel ectric Generation, September 2008

27 IGCC capture ready plants are assumed to be recirculating systems based on current regulations and concerns with once-through systems.

Figure 12 - Relative Water Usage for new PC and IGCC Plants

0 200 400 600 800 1,000 1,200 1,400 1,600Water (gal/MWhr)

Subcr itical PC Subcr itical PC w/ CO2 Captur e Super cr itical PC Super cr itical PC w/ CO2 Captur e IGCC IGCC w/ CO2 Captur e Withdrawal Consumption

* IGCC data are the averages of three different gasification technologies
Carbon capture technologies require auxiliary power also termed “parasitic” load, which lowers the net exported power. This analys is assumes that all new additions include carbon capture technologies and that these new builds will meet the required capacity by accounting for their own parasitic load. The existing PC plants th at will be retrofitted with carbon capture technologies will be de-rate d due to the parasitic load. Net outputs from retrofitted PC plants are de-rated by approximately 30% 15 , resulting in 79.3 GW of required replacement power. Since the EIA data did not include additions for a carbon capture case, this analysis looks at three possible scenar ios to account for the capacity loss.

Scenario 1 only accounts for the increased water requirements for the carbon capture technologies used for the retrofits and ne w builds and does not account for the 79.3 GW of reduced capacity due to the retrofits. For this analysis, it is assumed that the reduced capacity will be replaced with some other “non-thermoelect ric” generation that doesn’t require cooling water. The additional water requirements, if applicable, for these other technologies are not accounted for in this scenario. This scenar io is the lower estimate to serve as the lower boundary of th e projections and as the initi al step for the incremental water increase for scenarios 2 and 3 to build off of.

Scenario 2 builds off of scenario 1 and assu mes that the additional capacity needed to make up for the parasitic loss of the retrof its is supplemented by 79.3 GW of new IGCCFreshwater Needs for Thermoel ectric Generation, September 2008

28 plants with recirculating cooling and include carbon capture technologies. Cases 3 and 4 are applicable to these new builds where 10% of the new IGCC builds us saline water (Case 3) and 25% of the new builds use dry cooling (Case 4).

Scenario 3 is similar to scenar io 2 except it assumes that the additional capacity needed to make up for the parasitic loss of the retrofits is supplemented by 79.3 GW of new supercritical PC power plants with reci rculating cooling and include carbon capture technologies. Cases 3 and 4 are applicable to these new builds where 10% of the new supercritical builds us saline water (Case 3) and 25% of the new builds use dry cooling (Case 4).

Scenario 4 builds off of scenario 1 and assu mes that the additional capacity needed to make up for the parasitic loss of the retrof its is supplemented by 79.3 GW of new nuclear plants with recirculating cooling. This scenar io is only applied to Case 2 for this study.

PC and IGCC carbon capture techno logies increase the plants overall water use. For the PC cases with carbon capture, the increase in water consumption, compared to a plant without carbon capture, is greatly influenced by the cooling water requirements of the CO 2 capture process. The cooling water for the overall CO 2 capture process is required to reduce the flue gas temperature exiting th e FGD down to below 100°F, remove heat input by the stripping steam to cool the solv ent, remove heat input from the auxiliary electric loads, and remove heat in the CO 2 compressor intercoolers. 16 The increased water use for the IGCC plants in largely due to the steam used in the water gas shift reaction. More detail regarding the carbon capture tec hnologies used for this analysis is described in Appendix G.



### Results Both national and regional water withdrawal and consumption projections for each of the five cases are presented below for total th ermoelectric generation and the coal-fired generation component of thermoelectric ge neration. The increased water use for capturing CO 2 nationally in the ye ar 2030 is also shown.

Thermoelectric Generation – National Level Summary The analysis projects that by 2030, average daily national freshwater withdrawals required to meet the needs of U.S. thermo electric power genera tion could range from 112.4 BGD to 153.7 BGD depending upon case assump tions. The 2005 baseline value of 146 BGD compares incrementally to the USGS estimates that thermoelectric power plants withdrew approximately 132 BGD of freshwater in 1995 and approximately 136 BGD of freshwater in 2000. Table 7 presen ts the range of average daily national freshwater withdrawal for each of the five cases from 2005 through 2030. This same data is presented graphically in Figure 13.Freshwater Needs for Thermoel ectric Generation, September 2008

29 Table 7 – Average National F reshwater Withdrawal for Thermoel ectric Power Generation (BGD)

2005 2010 2015 2020 2025 2030

Case 1 146.3 148.1 143.2 149.6 153.5 153.7
Case 2 146.3 146.3 139.4 140.1 140.3 139.0
Case 3 146.3 146.2 139.4 140.0 140.2 138.9
Case 4 146.3 146.1 139.1 139.6 139.5 138.1
Case 5 146.3 140.2 127.5 122.9 118.3 112.4

Minimum 146.3 140.2 127.5 122.9 118.3 112.4

Maximum 146.3 148.1 143.2 149.6 153.5 153.7

Figure 13 – Average Daily National Freshwater Withdrawal for Thermoelectric Power Generation

0 40 80 120 160 200

2005 2010 2015 2020 2025 2030

YearDaily Withdrawals (BGD)

600 650 700 750 800 850 900ThermoelectricGenerating Capacity (GW)

Case 1

Case 2

Case 3

Case 4

Case 5

Generation

The analysis projects that by 2030, averag e daily national freshwater consumption resulting from U.S. thermoelectric power ge neration could range fr om 4.7 BGD to 5.5 BGD depending upon case assumptions. This compares with USGS estimates that in 1995, freshwater consumption by U.S. thermoel ectric power plants was approximately 3.3 BGD. Table 8 presents th e range of average daily national freshwater consumption for each of the five cases from 2005 thr ough 2030. This same data is presented graphically in Figure 14 along wit the gene rating capacity for each of the years.Freshwater Needs for Thermoel ectric Generation, September 2008

30 Table 8 – Average National Freshwater Consumpt ion for Thermoelectric Power Generation (BGD)

2005 2010 2015 2020 2025 2030

Case 1 3.7 3.8 4.0 4.2 4.5 4.7
Case 2 3.7 3.9 4.0 4.4 4.8 5.1
Case 3 3.7 3.9 4.0 4.4 4.7 5.0
Case 4 3.7 3.8 4.0 4.3 4.5 4.8
Case 5 3.7 3.9 4.2 4.6 5.1 5.5

Minimum 3.7 3.8 4.0 4.2 4.5 4.7

Maximum 3.7 3.9 4.2 4.6 5.1 5.5

Though the report primarily focuses on freshwater use, saline water usage is modeled and the results are included at the national leve l. Figure 15 and Figure 16 are similar to Figure 13 and Figure 14, except salin e water usage is added to th e graphs illustrating that nationally saline water withdrawals are appr oximately one-third th at of freshwater withdrawals. Saline water consumption for the thermoelectric plants is negligible compared to freshwater consumption, since mo st plants using saline water utilize a oncethrough cooling system.

Figure 14 – Average Daily Nation al Freshwater Consumption for Thermoelectric Power Generation

0 2 4 6

2005 2010 2015 2020 2025 2030

YearWater Consumption (BGD)

600 650 700 750 800 850 900ThermoelectricGenerating Capacity (GW)

Case 1

Case 2

Case 3

Case 4

Case 5

Generation

Thermoelectric Generation - National Level Results by Case

Case 1 Total thermoelectric generation freshwater w ithdrawal is projected to remain relatively constant from 2005 through 2030 for Case 1 – increasing slightly from 146.3 BGD to 153.7 BGD – despite the overall 18% increase in generation capacity from 700 GW toFreshwater Needs for Thermoel ectric Generation, September 2008

31 824 GW. At first glance this result seems in consistent with the Case 1 status quo assumptions that additions and retirements are proportional to curr ent water source and type of cooling water system. The explanatio n for this apparent inconsistency is that AEO2008 projects capacity retirements prim arily from the non-FGD coal and non-coal fossil generation categories, which have a relatively high propor tion of once-through cooling systems, while capacity additions are primarily in the FGD coal, IGCC, and NGCC generation categories, which have a rela tively high proportion of wet recirculating cooling systems. In addition, the steam cycle portion of IGCC and NGCC plants is only one-third of their total capacity. Since av erage freshwater withdrawal for once-through cooling is significantly higher than wet reci rculating cooling – a pproximately 25 gal/kWh versus 0.5 gal/kWh – the net effect is no significant change in overall freshwater withdrawal over the next 25 years.

Figure 15 – Average Daily National Freshwater and Saline Withdrawals fo r Thermoelectric Power Generation

0 20 40 60 80 100 120 140 160 180

2005 2010 2015 2020 2025 2030Water Withdrawals (BGD) FW Case1

FW Case 2

FW Case 3

FW Case 4

FW Case 5

SW Case 1

SW Case 2

SW Case 3

SW Case 4

SW Case 5Freshwater Needs for Thermoel ectric Generation, September 2008

32 Figure 16 – Average Daily National Freshwater and Saline Consumption fo r Thermoelectric Power Generation

0 1 2 3 4 5 6

2005 2010 2015 2020 2025 2030Water Consumption (BGD) FW Case1

FW Case 2

FW Case 3

FW Case 4

FW Case 5

SW Case 1

SW Case 2

SW Case 3

SW Case 4

SW Case 5

National freshwater withdrawal for each fuel type in Case 1 is presented in Figure 17. The figure shows the relatively unchanged total withdrawal, and the mirroring of scrubbed and unscrubbed coal (with scr ubbed increasing over time as unscrubbed decreases). There is a slight decrease in fossil non-coal with drawal and a slight increase in nuclear withdrawal.

Total thermoelectric generation freshwater consumption is projected to increase 27% from 2005 through 2030 for Case 1 – growing from 3.7 BGD to 4.7 BGD – consistent with the increase in generation capacity fr om 700 GW to 824 GW. Since once-through cooling systems have minimal water consump tion, the retirement of these systems does not have the same effect on na tional consumption levels as they do on withdrawal levels as described above.Freshwater Needs for Thermoel ectric Generation, September 2008

33 Figure 17 - Average Daily National Freshwater Withdrawal by Fuel for Thermoelectric Power Generation – Case 1

0 20 40 60 80 100 120 140 160

2005 2010 2015 2020 2025 2030

YearWithdrawal (BGD) TOTAL

Coal Unscrubbed Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

The changes in results over time reveal some interesting trends. Although total water withdrawal increases sligh tly between 2005 and 2030, the incr ease is not uniform. There is a dip in water withdrawal in the year 2015. This dip is dir ectly related to the dip in the total thermoelectric generation capacity wher e the initial decline is due to significant retirement of fossil non-coal capacity (more th an 24 GW) and the subsequent increase is due to new coal and combined-cycle additi ons (more than 12 GW). This difference appears in the other cases as well, alt hough to a lesser degree because of competing influences unique to each specific case.

The growing importance of IGCC technology is evident in the re sults over time. From a level of less than 500 MW in 2005, IGCC is expected to account for 29.5 GW by 2030. While this capacity impact is large, the wate r impact is remarkably small – due primarily to the assumption that all new IGCC capacity will be equipped with wet recirculating cooling. In 2030, water wit hdrawal for IGCC is only 0.264 BGD and water consumption is 0.205 BGD.

National freshwater consumption for each fuel t ype in Case 1 is presented in Figure 18. The effects of increased use of NGCC and IGCC can more clearly be seen in the consumption graph than in the previous with drawal graph. Consumption increases for each fuel type except unscrubbed coal and fossil non-coal, which decrease. Nuclear water consumption remains constant until 2020 when new additions are expected to be online.Freshwater Needs for Thermoel ectric Generation, September 2008

34 Figure 18 - Average Daily National Freshwater Consumption by Fuel fo r Thermoelectric Power Generation – Case 1

0 1 2 3 4 5

2005 2010 2015 2020 2025 2030

YearConsumption (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Case 2 Total thermoelectric generation freshwater withdrawal is pr ojected to decrease approximately 5% (146.3 BGD to 139 BGD) from 2005 through 2030 for Case 2. This trend is consistent with the assumptions that all capacity additions use freshwater and wet recirculating cooling systems, while capac ity retirements are pr oportional to current water source and type of cooling water system.

Figure 19 displays Case 2 nationa l withdrawal for each fuel t ype. The decrease in total withdrawal can be seen along with a decrease in fossil non-coal. The line representing the combination of scrubbed and unscrubbed co al remains relatively constant. Again scrubbed coal increases, while unscrubbed decreases.

Similar to Case 1, total thermoelectric generati on freshwater consump tion is projected to increase – growing 40% from 3.7 BGD to 5.1 BGD between 2005 and 2030 – consistent with both the 18% increase in generation cap acity and increased use of wet recirculating cooling water systems.

Figure 20 displays Case 2 national consum ption for each fuel type. Consumption increases are seen in every fuel type excep t unscrubbed coal, combined cycle, and fossil non-coal, which decrease.Freshwater Needs for Thermoel ectric Generation, September 2008

35 Figure 19 - Average Daily National Freshwater Withdrawal by Fuel for Thermoelectric Power Generation – Case 2

0 20 40 60 80 100 120 140 160

2005 2010 2015 2020 2025 2030

YearWithdrawal (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Case 3 The Case 3 assumptions are similar to Case 2, except that 90% of capacity additions use freshwater and wet recirculating cooling and 10% use saline wa ter with once-through cooling. As might be expected, both ther moelectric generation freshwater withdrawal and consumption levels for Case 3 are slight ly less than the respective values from Case 2. In 2030, freshwater withdrawal is 139 BGD in Case 2 compared to 138.9 in Case 3. Similarly, freshwater consumption in 2030 is 5.1 BGD and 5.0 BGD for Cases 2 and 3, respectively.

National freshwater withdrawal for each fuel type in Case 3 is presented in Figure 21. As the figure shows, total withdrawal decreas es over time. Fossil non-coal and coal unscrubbed also display a noticeable decrease. National freshwater consumption for each fuel type in Case 3 is presented in Figur e 22. Freshwater consumption is shown to increase over time. As with previous consumption cases, only coal unscrubbed and fossil non-coal consumption decreases from 2005 to 2030.Freshwater Needs for Thermoel ectric Generation, September 2008

36 Figure 20 - Average Daily National Freshwater Consumption by Fuel fo r Thermoelectric Power Generation – Case 2

0 1 2 3 4 5 6

2005 2010 2015 2020 2025 2030

YearConsumption (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Figure 21 - Average Daily National Freshwater Withdrawal by Fuel for Thermoelectric Power Generation – Case 3

0 20 40 60 80 100 120 140 160

2005 2010 2015 2020 2025 2030

YearWithdrawal (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

NuclearFreshwater Needs for Thermoel ectric Generation, September 2008

37 Figure 22 - Average Daily National Freshwater Consumption by Fuel fo r Thermoelectric Power Generation – Case 3

0 1 2 3 4 5 6

2005 2010 2015 2020 2025 2030

YearConsumption (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Case 4 The potential impact of dry cooling systems on water demand is evident in the results of Case 4, where 25% of new capacity is assumed to be equipped with dry cooling, rather than wet recirculating cooling. Thermoelect ric generation freshwater withdrawal and consumption levels for Case 4 are less than the respective values from Case 2. By 2030, freshwater withdrawal is proj ected to be approximately 1% less in Case 4 compared to Case 2 – 138.1 BGD vs. 139.0 BGD. More si gnificantly, freshwater consumption is projected to be approximately 6% less – 4.8 BGD in Case 4 vs. 5.1 BGD in Case 2. The results suggest that dry cooling has the poten tial to play a significant roll in minimizing freshwater consumption in future years if technology is developed to cost effectively build and operate dry cooling plants.

Figure 23 displays Case 4 national withdrawal for each fuel type. The total freshwater withdrawal decreases over time, as does coal unscrubbed and fossil non-coal. The line representing the combination of scrubbed a nd unscrubbed coal remains rather constant over the time period. Figure 24 displays Case 4 national consumption for each fuel type. Total consumption is shown to increase from 2005 to 2030, with only coal unscrubbed and fossil non-coal decrea sing during that period.Freshwater Needs for Thermoel ectric Generation, September 2008

38 Figure 23 - Average Daily National Freshwater Withdrawal by Fuel for Thermoelectric Power Generation – Case 4

0 20 40 60 80 100 120 140 160

2005 2010 2015 2020 2025 2030

YearWithdrawal (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Figure 24 - Average Daily National Freshwater Consumption by Fuel fo r Thermoelectric Power Generation – Case 4

0 1 2 3 4 5 6

2005 2010 2015 2020 2025 2030

YearConsumption (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Case 5 The Case 5 assumptions for capacity additions and retirements are the same as Case 2. However, Case 5 also assumes that 25% of existing freshwater once-through cooling capacity is converted to wet reci rculating cooling. As a result, Case 5 represents the most extreme conditions of the analysis and si gnificantly impacts projections for both freshwater withdrawal and consumption. By 2030, total thermoelectric generation freshwater withdrawal is proj ected to be approximately 19% less in Case 5 compared to Case 2 – 112.4 BGD vs. 139.0 BGD – while consumption is projected to be approximately 8% more – 5.5 BGD in Case 5 vs. 5.1 BGD in Case 2.Freshwater Needs for Thermoel ectric Generation, September 2008

39 Figure 25 - Average Daily National Freshwater Withdrawal by Fuel for Thermoelectric Power Generation – Case 5

0 20 40 60 80 100 120 140 160

2005 2010 2015 2020 2025 2030

YearWithdrawal (BGD) TOTAL

Coal Unscrubbed Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

Figure 26 - Average Daily National Freshwater Consumption by Fuel fo r Thermoelectric Power Generation – Case 5 p

0 1 2 3 4 5 6

2005 2010 2015 2020 2025 2030

YearConsumption (BGD) TOTAL

Coal Unscrubbed

Coal Scrubbed

Coal w / & w /out Scrubber Fossil Non-Coal

Combined Cycle

IGCC

Nuclear

National freshwater withdrawal for each fuel type in Case 5 is presented in Figure 25. Total freshwater withdrawal decreases over ti me, as does withdrawal for all fuel typesFreshwater Needs for Thermoel ectric Generation, September 2008

40 except scrubbed coal (which increases as unscrubbed coal decreases). National freshwater consumption for each fuel type in Case 5 is presented in Figure 26. As with previous consumption cases, total freshwate r consumption increases and unscrubbed coal and fossil non-coal are the only fuel types shown to decrease. Thermoelectric Generation – Regional Results

Figure 27 through Figure 31 show the results of the regional freshwater withdrawal analysis for total U.S. thermoelectric gene ration comparing 2005 to 2030 for each of the five cases. The graphs show the SERC re gion has the largest increase in water withdrawal generally among the cases. The ECAR and ERCOT regions experience the largest decreases in water withdrawal in each case. Figure 32 through Figure 36 show the results of the regional freshwater consumpti on analysis for total U.S. thermoelectric generation comparing 2005 to 2030 for each of the five cases. All regions, except California, show an increase in water cons umption. Inverse to the water withdrawal regional data, the regional consumption gr aphs indicate that the ECAR and ERCOT regions, along with the western regions WECC/NWPP and WECC/RM are all increasing water consumption significantly.

Case 1 As discussed previously, total thermoelect ric generation freshwater withdrawal is projected to remain relativel y constant from 2005 through 2030 for Case 1 – increasing slightly from 146.3 BGD to 153.7 BGD On a regional basis, freshwater withdrawal increases in the MAIN, MAPP, WPCC/ NE FRCC, SERC, SPP, WECC/NWPP, WECC/RM, and WECC/CA regions. The FRCC region shows the greatest relative water withdrawal increase, 77% by the year 2030. Decr eases occurred in all other regions, with the most significant decreases in the NPCC/ NY, ECAR, and ERCOT regions (Figure 27).

Total thermoelectric generation freshwater consumption is projected to increase 28% from 2005 through 2030 for Case 1 – growing from 3.7 BGD to 4.7 BGD. Freshwater consumption increases in 12 of the 13 regions, with relatively large percentage increases occurring in the NPCC/NY (204%), FRCC (86%), and WECC/RM (82%) WECC/CA shows a (27%) decrease in wa ter consumption (Figure 32).Freshwater Needs for Thermoel ectric Generation, September 2008

41 Figure 27 – Average Daily Regional Freshwater Wi thdrawal for Thermoelectric Power Generation – Case 1

-10

0 10 20 30 40 50 60

EC A

R
E RC

O

T MA AC M AIN M AP

P

N

PCC / N Y

N

PC

C/

N

E FR C

C SE R C SPP

W

E C

C/

N WP

P WECC / RM

WECC / C AWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030

Figure 28 – Average Daily Regional Freshwater Wi thdrawal for Thermoelectric Power Generation – Case 2

-10

0 10 20 30 40 50

E CA

R
E RC

O

T MA A C M AIN M AP

P

N

PC

C/

N Y

N

PC

C/

N

E
F RC

C S ER

C S P

P

W

E C

C/

N W

P P

W

E

C

C/

R

M

W

E

C

C/

C AWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

42 Figure 29 – Average Daily Regional Freshwater Wi thdrawal for Thermoelectric Power Generation – Case 3 Case 3

-10

0 10 20 30 40 50

ECA R
E RC

O

T MA AC M AI

N M APP

N

PCC / NY

NP

C

C/

N

E FRC C SE RC S P

P

W

EC

C / NW

P P

W

E CC

/ RM

W

E CC

/ CAWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030

Figure 30 – Average Daily Regional Freshwater Wi thdrawal for Thermoelectric Power Generation – Case 4

-10

0 10 20 30 40 50

ECAR
E R

CO

T M AA

C M A

IN M A

PP

N

PCC / N Y

N

PC

C/

N

E FRCC SE R

C SP P

W

E

CC

/ NWP P

W

E CC

/ R

M

W

E CC

/ C

AWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

43 Figure 31 – Average Daily Regional Freshwater Wi thdrawal for Thermoelect ric Power Generation – Case 5

-20 -10

0 10 20 30 40 50

ECA R
E R

CO

T M AA

C MAIN MA P P

NPC C /N

Y

N

P CC/NE FRC C SER C SP P WE

C

C/NW P P WEC C /R

M WEC C /C

AWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030

Figure 32 – Average Daily Regional Freshwater Consumption for Thermoelect ric Power Generation – Case 1

-0.5 0.0 0.5 1.0 1.5 2.0

E C

AR
E RCOT MAAC MAIN M A

PP

NP

C

C/

N Y

N

PCC / NE
F R

CC SE RC SPP WECC/N W

P P WECC/RM

W

E

C

C/

C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

44 Figure 33 – Average Daily Regional Freshwater Consumption for Thermoelect ric Power Generation – Case 2

-0.5 0.0 0.5 1.0 1.5

ECAR ER C

O

T M AA

C MA I N MAPP

N

PCC / N Y

N

P CC

/ NE
F RC

C SERC SP P WECC/NWP P

W

E CC

/ R

M WEC C /CAConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030

Figure 34 – Average Daily Regional Freshwater Consumption for Thermoelect ric Power Generation – Case 3

-0.5 0.0 0.5 1.0 1.5

ECAR ER C

OT MAAC M A

IN MA P P

NPCC/NY NP

CC

/ N

E FRCC SERC S PP

W

E

C

C/

N W

P P WEC C / R

M WECC/C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

45 Figure 35 – Average Daily Regional Freshwater Consumption for Thermoelect ric Power Generation – Case 4

-0.5 0.0 0.5 1.0 1.5 2.0

EC A

R ERC O

T MAAC M AI

N M A

PP

N

P CC/NY

N

PCC / NE
F R

CC SE R C SPP

W

E CC

/ NWP P WECC/RM

W

E

C

C/

C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030

Figure 36 – Average Daily Regional Freshwater Consumption for Thermoelect ric Power Generation – Case 5

-0.5 0.0 0.5 1.0 1.5

EC A

R ERCOT M A

AC MAIN MAPP NP

CC

/ NY

NP

CC

/ N

E FRCC SE R C S P

P

W

E CC

/ NWP P WECC/RM

W

E

C

C/

C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

46 Case 2 Total thermoelectric generation freshwater withdrawal is pr ojected to decrease approximately 5% (146.3 BGD to 139.0 BGD) from 2005 through 2030 for Case 2. Similar to Case 1, total thermoelectric generati on freshwater consump tion is projected to increase – growing 40% from 3.7 BGD to 5.1 BGD between 2005 and 2030. On a regional basis, freshwater withdrawal in creases slightly in the FRCC, NPCC/NE, WECC/RM, WECC/CA, and WECC/NWPP re gions; and decreases in the ECAR, ERCOT, MAAC, MAIN, MAPP, NPCC/NY, and SPP regions (Figure 28). Similar to Case 1, freshwater consumption increases in al l of the regions, excep t in WECC/CA, with relatively large percentage increases occurr ing in the NPCC/NY (207%), FRCC (336%), NPCC/NE (93%), and WECC/NW PP (80%) regions (Figure 33).

Case 3 Both thermoelectric generation freshwater wi thdrawal and consumption levels for Case 3 are slightly less than the respective values from Case 2. In 2030, freshwater withdrawal is 139.0 BGD in Case 2 compared to 138.9 in Ca se 3. Similarly, freshwater consumption in 2030 is 5.1 BGD and 5.0 BGD for Cases 2 a nd 3, respectively. On a regional basis, freshwater withdrawal and c onsumption increases and decreases are also similar to Case 2 (Figure 29 and Figure 34).

Case 4 Thermoelectric generation freshwater withdraw al and consumption levels for Case 4 are less than the respective values from Case 2. By 2030, freshwater with drawal is projected to be approximately 1% less in Case 4 co mpared to Case 2 – 138.1 BGD vs. 139.0 BGD. More significantly, freshwater consumption is projected to be approximately 6% less – 4.8 BGD in Case 4 vs. 5.1 BGD in Case 2. On a regional basis, freshwater withdrawal and consumption increases and decreases are al so similar to Case 2 (Figure 30 and Figure 35).

Case 5 The Case 5 assumptions for capacity additions and retirements are the same as Case 2, but Case 5 also assumes that 25% of existi ng freshwater once-through cooling capacity is converted to wet recirculating cooling. By 2030, total thermoelectric generation freshwater withdrawal is proj ected to be approximately 19% less in Case 5 compared to Case 2 – 112.4 BGD vs. 139.0 BGD – while consumption is projected to be approximately 8% more – 5.5 BGD in Case 5 vs. 5.1 BGD in Case 2. On a regional basis, freshwater withdrawal increases in the FRCC (31%) and WECC/NWPP (27%) regions; and decreases in all other regions, w ith significant decrease s 25% or greater in the NPCC/NY (35%), ECAR (24%), and ERCO T (37%) regions (Figure 31). Freshwater consumption increases in all of the regions, with relatively large percentage increases occurring in the NPCC/NE (103%), NPCC/NY (387%), and FRCC (337%) regions (Figure 36). Freshwater consump tion for WECC/CA decreased (20%).

Saline Regional ResultsFreshwater Needs for Thermoel ectric Generation, September 2008

47 Figure 37 shows the regional saline water wi thdrawal and Figure 38 shows the saline water consumption analyses for total U.S. thermoelectric generation comparing 2005 to 2030 for Case 3. The 2008 water analysis primar ily focuses on freshwater usage. These are the only two regional figures representing saline water use in this study. Only Case 3 was chosen to show the regiona l saline water uses because this case has the highest saline water withdrawal and consump tion of the five cases.

On a regional basis, saline water withdrawal increases in ten regions , with relatively large percentage increases occurring in the EC AR (379%), MAPP (112%), and WECC/NWPP (176%) regions; and only slight ly decreases in the other three regions. (Figure 37). Saline water consumption increases in 12 of the 13 regions, with relatively large percentage increases occurring in the NPCC/NE (543%), WECC/NWPP (246%, MAPP (141%), SPP (131%), ERCOT (111%), a nd MAIN (195%) regions (Figure 38).Freshwater Needs for Thermoel ectric Generation, September 2008

48 Figure 37 – Average Daily Regional Saline Wate r Withdrawal for Thermoel ectric Power Generation – Case 3

-2 0 2 4 6 8 10 12

E CA

R
E RC

O

T M A

AC M AIN M APP

N

PCC / NY

NP

C

C/

N

E
F RCC S ERC S PP WECC/NWP P WECC/RM WECC / CAWithdrawals (BGD)

Water Withdrawal, 2005 Incremental Water Withdrawal, 2005 - 2030

Figure 38 – Average Daily Regional Saline Water Consumption for Thermoelectric Power Generation – Case 3

-0.02 -0.01 0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07

EC A

R ERCOT M A

AC MAIN M A

PP

N

P CC

/ NY

N

PCC/N E FR CC SE R C S PP WECC/N W

P P

W

E

CC

/ R

M WECC/CAConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

49 Conventional Coal-Fired Generation – National Level Summary Conventional coal-fired (not including IGCC) generating capac ity is projected to increase by 67 GW from 2005 to 2030. The analysis pr ojects that by 2030, average daily national freshwater withdrawals required to meet th e needs of the U.S. coal-fired generation component of thermoelectric generation may d ecrease to 76.9 BGD (1 7%) or increase to 103.7 BGD (12.8%) depending upon case assumptions . Table 9 presents the range of average daily national freshw ater withdrawal for each of the five cases from 2005 through 2030. This same data is pr esented graphically in Figure 39.

Table 9 –Average National Freshwater Withdrawal for Conventional Coal Power Generation (BGD)

2005 2010 2015 2020 2025 2030

Case 1 91.9 94.2 96.0 98.0 102.0 103.6
Case 2 91.9 92.3 92.2 92.4 92.6 92.8
Case 3 91.9 92.3 92.2 92.4 92.5 92.7
Case 4 91.9 92.1 91.9 92.0 92.0 92.0
Case 5 91.9 88.8 85.2 82.2 79.4 76.7

Maximum 91.9 94.2 96.0 98.0 102.0 103.6

Minimum 91.9 88.8 85.2 82.2 79.4 76.7

Figure 39 –Average Daily National Freshwater Withdrawal for Conventional Coal Power Generation

0 20 40 60 80 100 120

2005 2010 2015 2020 2025 2030
YearWater Withdrawal (BGD)

250 300 350 400Coal-Fired Generation (GW)

Case 1

Case 2

Case 3

Case 4

Case 5

Coal Generation

The analysis projects that by 2030, averag e daily national freshwater consumption resulting from U.S. coal-fired power ge neration could range fr om 3.3 BGD to 3.7 BGD depending upon case assumptions. This represen ts an increase of 36% and 55 % respectively. Table 10 presents the range of average daily national freshwaterFreshwater Needs for Thermoel ectric Generation, September 2008

50 consumption for each of the five cases fr om 2005 through 2030. This same data is presented graphically in Figure 40.

Table 10 – Average National F reshwater Consumption for Conventi onal Coal Power Generation (BGD)

2005 2010 2015 2020 2025 2030

Case 1 2.4 2.5 2.6 2.9 3.1 3.3
Case 2 2.4 2.5 2.7 3.0 3.3 3.5
Case 3 2.4 2.5 2.7 3.0 3.2 3.4
Case 4 2.4 2.5 2.7 2.9 3.1 3.3
Case 5 2.4 2.6 2.8 3.1 3.5 3.7

Maximum 2.4 2.6 2.8 3.1 3.5 3.7

Minimum 2.4 2.5 2.6 2.9 3.1 3.3

Figure 40 – Average Daily National Freshwater Consumption for Conventional Coal Power Generation

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5

2005 2010 2015 2020 2025 2030

YearWater Consumption (BGD)

250 300 350 400Coal-Fired Generation (GW)

Case 1

Case 2

Case 3

Case 4

Case 5

Coal Generation

Conventional Coal-Fired Generation - National Level Results by Case

Case 1 The conventional coal portion of thermoelectri c generation freshwater withdrawal is projected to increase approximately 13% from 2005 through 2030 for Case 1 – from 91.9 BGD to 103.6 BGD – consistent with the overall 22% increase in generation capacity from 309 GW to 3376 GW and roughly equa l distribution of once-through and wet recirculating cooling water systems. More significantly, conventional coal generation freshwater consumption is projected to in crease 38% from 2005 through 2030 for Case 1Freshwater Needs for Thermoel ectric Generation, September 2008

51 – growing from 2.4 BGD to 3.3 BGD. See Figure 17 and Figure 18 for plots of coal withdrawal and cons umption from 2005-2030.

Case 2 Conventional coal generation freshwater withdr awal is projected to slightly increase by less than 1% (91.9 BGD to 92.8 BGD) from 200 5 through 2030 for Case 2. This trend is consistent with the assumptions that all capacity additions use freshwater and wet recirculating cooling systems, while capac ity retirements are pr oportional to current water source and type of cooling water system.

Similar to Case 1, conventional coal generatio n freshwater consumption is projected to increase in Case 2 – growing 46% fr om 2.4 BGD to 3.5 BGD between 2005 and 2030 – consistent with both the 22% increase in generation capacity and increased use of wet recirculating cooling water systems. S ee Figure 19 and Figure 20 for plots of coal withdrawal and cons umption from 2005-2030.

Case 3 The Case 3 assumptions are similar to Case 2, except that 90% of capacity additions use freshwater and wet recirculating cooling and 10% use saline wa ter with once-through cooling. As might be expected, both convent ional coal generation freshwater withdrawal and consumption levels for Case 3 are slight ly less than the respective values from Case 2. In 2030, freshwater withdrawal is 92.8 BGD in Case 2 compared to 92.7 in Case 3. Similarly, freshwater consumpti on in 2030 is 3.5 BGD and 3.3 BGD for Cases 2 and 3, respectively. See

Figure 21 and Figure 22 for plots of coal withdrawal and consumption from 2005-2030.

Case 4 The potential impact of dry cooling systems on water demand is evident in the results of Case 4, where 25% of new conventional coal ca pacity is assumed to be equipped with dry cooling, rather than wet recirculating cooli ng. Conventional coal generation freshwater withdrawal and consumption levels for Case 4 are less than the respective values from Case 2. By 2030, freshwater withdrawal is proj ected to be slightly less in Case 4 – 92.0 BGD compared to Case 2 – 92.8 BGD. Fres hwater consumption is projected to be approximately 7% less – 3.3 BGD in Case 4 vs. 3.5 BGD in Case 2. See Figure 23 and Figure 24 for plots of coal withdr awal and consumption from 2005-2030.

Case 5 The Case 5 assumptions for conventional coal capacity additions and retirements are the same as Case 2. However, Case 5 also a ssumes that 25% of existing freshwater oncethrough cooling capacity is converted to wet recirculating cooling. As a result, Case 5 represents the most extreme conditions of the analysis and significantly impacts projections for both freshwater withdr awal and consumption. By 2030, total conventional coal generation freshwater withdr awal is projected to be approximately 17%Freshwater Needs for Thermoel ectric Generation, September 2008

52 less in Case 5 compared to Case 2 – 76.7 BGD vs. 92.8 BGD – while consumption is projected to be approximately 6% more – 3.7 BGD in Case 5 vs. 3.5 BGD in Case 2. See Figure 25 and Figure 25 for plots of coal withdrawal and consumption from 2005-2030.

Conventional Coal-Fired Generation – Regional Results Figure 41 through Figure 45 shows the results of the regional water withdrawal analysis for total U.S. coal-fired generation compari ng 2005 to 2030 for each of the five cases. With each successive case, the water withdr awal of the regions displays greater decreases, with Case 5 showing the largest ov erall decrease in water withdrawal. Figure 46 through Figure 50 show the results of the regional water consumption analysis for total U.S. coal-fired generation comparing 2005 to 2030 for each of the five cases. Aside from Case 5, where water consumption incr eases more than other cases, the water consumption regionally st ays rather consistent.

Case 1 Conventional coal generation freshwater withdrawal is projected to increase approximately 13% from 2005 through 2030 fo r Case 1 – from 91.9 BGD to 103.6 BGD. Conventional coal freshwater consumption is projected to incr ease 38% from 2005 through 2030 for Case 1 – growing from 2.4 BGD to 3.3 BGD. On a regional basis, freshwater withdrawal increases in all re gions except in the NPCC/NY region (Figure 41). Freshwater consumption increases in a ll of the regions, except in WECC/CA, with relatively large percentage increases occu rring in the FRCC (145%), ERCOT (113%), and WECC/RM (120%) regions (Figure 46).

Case 2 Conventional coal generation freshwater withdrawal is proj ected to decrease approximately 1% (91.9 BGD to 92.8 BGD) from 2005 through 2030 for Case 2. Similar to Case 1, conventional coal generation freshw ater consumption is projected to increase in Case 2 – growing 46% from 2.4 BGD to 3.5 BGD between 2005 and 2030. On a regional basis, freshwater withdrawal incr eases in all regions except for ECAR, MAIN, and NPCC/NY (Figure 42). Simila r to Case 1, freshwater cons umption increases in all of the regions, except for WECC/CA with relativel y large percentage increases occurring in the ERCOT (276%), FRCC (341%), and WECC/RM (110%) regions (Figure 47).

Case 3 Both conventional coal generation freshwater withdrawal and consumption levels for Case 3 are slightly less than the respective values from Ca se 2. In 2030, freshwater withdrawal is 92.8 BGD in Case 2 compared to 92.7 in Case 3 (Figure 43). Similarly, freshwater consumption in 2030 is 3.5 BGD and 3.4 BGD for Cases 2 and 3, respectively (Figure 48). On a regional basis, freshwat er withdrawal and consumption increases and decreases are also similar to Case 2.Freshwater Needs for Thermoel ectric Generation, September 2008

53 Figure 41 – Average Daily Regional Freshwater Withdrawal for Coal-Fired Power Generation – Case 1

-5 0 5 10 15 20 25 30 35

EC A

R ERC O

T M AAC M A

IN MAPP NPC C / NY NPCC/NE FR CC SE RC SPP WECC/N W

P P WEC C / R

M

W

E C

C/CAWithdrawals (BGD)

Water Withdrawl, 2005 Incremental Water Withdraw, 2005 - 2030

Figure 42 – Average Daily Regional Freshwater Withdrawal for Coal-Fired Power Generation – Case 2

-5 0 5 10 15 20 25 30

E CA

R
E R

COT M A

AC MA I N M A

PP

N

PC

C/

N Y

NPCC/NE FR C

C S ER

C SPP

W

E

CC/NWP P WEC C /R

M

W

E C

C/

C

AWithdrawals (BGD)

Water Withdrawl, 2005 Incremental Water Withdraw, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

54 Figure 43 – Average Daily Regional Freshwater Withdrawal for Coal-Fired Power Generation – Case 3

-5 0 5 10 15 20 25 30

ECAR ERCOT M A

AC MA I N MA PP NPC C /N

Y

N

P CC/NE FR C

C SE R

C SP P

W

E

CC

/ N W

P P WECC/RM WECC/CAWithdrawals (BGD)

Water Withdrawl, 2005 Incremental Water Withdraw, 2005 - 2030

Figure 44 – Average Daily Regional Freshwater Withdrawal for Coal-Fired Power Generation – Case 4

-5 0 5 10 15 20 25 30

EC A

R
E RCOT MA AC MAI N MAPP NPC C / NY NPC C / NE FR C

C SER C SPP WECC / N W

P P

W

EC

C / R

M WE

C

C/CAWithdrawals (BGD)

Water Withdrawl, 2005 Incremental Water Withdraw, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

55 Figure 45 – Average Daily Regional Freshwater Withdrawal for Coal-Fired Power Generation – Case 5

-10

-5 0 5 10 15 20 25 30 35

E C

AR
E RCOT MA A C MAIN M AP

P

N

P CC/NY

N

PCC / N

E FR C

C S E

RC SP P WEC C / NW

P P WECC/RM

W

E

CC

/ CAWithdrawals (BGD)

Water Withdrawl, 2005 Incremental Water Withdraw, 2005 - 2030

Figure 46 – Average Daily Regional Freshwater Consumption for Coal-Fired Power Generation – Case 1

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

E

C

AR ERCOT MA A

C MA I N MAPP NPCC/ N

Y

N

P

CC / NE FRCC S E

RC SPP WECC/NWPP WE CC / RM WECC/CAConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

56 Figure 47 – Average Daily Regional Freshwater Consumption for Coal-Fired Power Generation – Case 2

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

ECAR ERCOT M AAC M A

IN MAPP NPCC/NY

N

P CC

/ NE FRC C SER C SP P WECC/NWP P WEC C / R

M WECC/ C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030

Figure 48 – Average Daily Regional Freshwater Consumption for Coal-Fired Power Generation – Case 3

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

E CA

R ERC O

T MAAC M A

IN M A

PP

N

P CC/NY

N

PCC / NE FRCC SERC SP P WECC/NWP P

W

EC

C / RM

W

EC

C / C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

57 Figure 49 – Average Daily Regional Freshwater Consumption for Coal-Fired Power Generation – Case 4

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7

EC A

R ERC O

T M AAC M A

IN MAPP NPC C / NY

N

P CC

/ NE FRC C SE R

C SPP WECC / N W

P P WEC C / R

M WECC/ C AConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030

Figure 50 – Average Daily Regional Freshwater Consumption for Coal-Fired Power Generation – Case 5

-0.1 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8

E C AR ER COT M A

AC MA IN MAP P

NPCC/N Y

NPCC/NE FR C

C SERC S PP WEC C/

NWP P WECC/RM WECC / CAConsumption (BGD)

Water Consumption, 2005 Incremental Water Consumption, 2005 - 2030Freshwater Needs for Thermoel ectric Generation, September 2008

58 Case 4 Conventional coal generation freshwater wit hdrawal and consumption levels for Case 4 are less than the respective values from Ca se 2. By 2030, freshwater withdrawal is projected to be slightly less in Case 4 compared to Case 2 – 92.8 BGD vs. 92.0 BGD (Figure 44). Freshwater consumption is pr ojected to be approximately 6% less – 3.3 BGD in Case 4 vs. 3.5 BGD in Case 2 (Fi gure 49). On a regional basis, freshwater withdrawal and consumption increases and decreases are also similar to Case 2.

Case 5 By 2030, total conventional coal generation fre shwater withdrawal is projected to be approximately 17% less in Case 5 compared to Case 2 – 76.7 BGD vs. 92.8 BGD – while consumption is projected to be approximate ly 6% more – 3.7 BGD in Case 5 vs. 3.5 BGD in Case 2. On a regional basis, freshwater withdrawal increases very slightly in the ERCOT , FRCC, WECC/NWPP, WECC/RM and WECC/CA regions; and decreases significantly in the NPCC/NY (32%), ECAR (20%), and MAAC (20%) regions (Figure 45). Freshwater consumption increases in all of the regions, with relatively large percentage increases occurring in the NPCC/NE (285%), NPCC/NY (319%), ECAR (35%), MAIN (115%), SERC (28%), FRCC (344%), ERCOT (276%), WECC/RM (110%), and WECC/NWPP (92%) regions (Figure 50).

Carbon Capture Deployment Analysis

The carbon capture deployment analysis uses th e same five cases for the types of cooling systems for the new plant additions. All wa ter withdrawal and c onsumption results in this analysis are for freshwater. The analysis also assumes four aggressive scenarios for the additions required to supplement the decrease in capacity for the PC plants retrofitted with carbon capture technologies as described in the Assumptions and Methodology section of this report. The pr ojected results of a ll of the scenarios for PC plants with scrubbers and IGCC plants with 90% CO 2 capture, for the year 2030, show an increase in water withdrawal and consumption over the non-capture scenario. Figure 51 and Figure 53 show the results for the five cases and four scenarios with respect to all thermoelectric generation.

Figure 51 shows the additional amount of water withdrawal if all of the forecasted PC plants with scrubbers and IGCC plants were to depl oy carbon capture technologies, compared to all thermoelectric plants without carbon capture technologies for the projected year 2030. The Case 2 column in Figure 51 shows that in 2030, 139 BGD of water withdrawal is projected for all ther moelectric plants without carbon capture deployment. Scenario 1 shows by retrofitti ng carbon capture technolog ies to the existing scrubbed coal-fired fleet and deploying capture ready technologies to all new additions, an additional 3.6 BGD would be required, resul ting in a total of 142.6 BGD. If Scenario 2 is applied, building all IGCC plants for th e replacement power lost to the retrofits, 0.8 BGD would be added to Scenario 1, result ing in a total of 143.4 BGD. Scenario 3, building all PC supercritical plants for the replacement power, would add 2.1 BGD to Scenario 1 resulting in a to tal of a 144.7 BGD withdrawal. Scenario 4 withdrawals theFreshwater Needs for Thermoel ectric Generation, September 2008

59 most water of the four scenarios, adding 2.5 B GD to Scenario 1 and resulting in a total of 145 BGD withdrawal. Since reci rculating cooling systems are used in all scenarios, water withdrawal is low rela tive to water consumption.

Figure 51 - Thermoelectric Generation with Addi tional Water Withdraw al for PC and IGCC Carbon Capture Deployment for Year 2030

0 40 80 120 160Water Withdrawal(BGD)

12345

Case Scenario 4

Scenario 3

Scenario 2

Scenario 1

All Non-Capture Thermoelectric Plants

Figure 52 illustrates the breakdow n of Scenario 1, a closer look at scenarios 2 and 3, and presents the results for scenario 4 as applied to Case 2. The bottom section of the blue bars represent the additional wa ter withdrawal required for th e existing PC retrofits, 2.8 BGD. The top section of the blue bars repres ent the additional water withdrawal required for the carbon capture techno logies of the new PC a nd IGCC capacity, 0.7 BGD. Therefore, Scenario 1 would require a total of 3.5 BGD. Scenario 2 would include the 3.5 BGD plus an additional 0.8 BGD of water withdrawal for the new IGCC plants built to replace the power lost to the retrofits fo r a total 4.3 BGD. Scen ario 3 is similar to Scenario 2 except instead of IGCC plants bu ilt to make up the power loss, supercritical PC plants would be built. These supercri tical PC plants woul d require 2.1 BGD water withdrawal and combined with the Scenario 1 demand, woul d require a total 5.6 BGD. Scenario 4, additional nuclear plants built to replace the power lost to the retrofits, would add 2.5 BGD to scenario1 for a tota l water withdrawal of 6.0 BGD.Freshwater Needs for Thermoel ectric Generation, September 2008

60 Figure 52 – Additional Water Withdrawal of CO 2 Capture Scenarios – Case 2

0 1 2 3 4 5 6 7Water Withdrawal(BGD)

1234

Scenario New Nuclear Replacement Power New PC Replacement Power New IGCC Replacement Power
New PC and IGCC with CO2 Existing PC Retrofits with CO2

Figure 53 shows the additional amount of water consumption if all of the forecasted PC with scrubbers and IGCC plants were to de ploy carbon capture technologies compared to all thermoelectric plants without carbon capture technologies. The Ca se 2 data in Figure 53 shows that in 2030, 5.1 BGD of water consum ption is projected for all thermoelectric plants without car bon capture deployment. Scenar io 1 shows by deploying carbon capture technologies to the scrubbed coal-fired fleet, an additional 2.5 BGD would be required, resulting in a total of 7.6 BGD. If Scenario 2 is applied, 0.7 BGD would be added to Scenario 1, resulting in a total of 8.3 BGD. Scenario 3 would add 1.6 BGD to Scenario 1 resulting in a total water consump tion of 9.2 BGD for Scenario 3. Scenario 4 adds 1.3 BGD to Scenario 1 and results in a total of 8.9 BGD consum ed. Scenarios 3 and 4 consume the same amount of water when a pplied to Case 4 and are plotted as one column segment noted by the two-colored bars.

Figure 53 - Thermoelectric Generation with Addi tional Water Consumpt ion for PC and IGCC Carbon Capture Deployment for Year 2030

0 1 2 3 4 5 6 7 8 9 10Water Consumption(BGD)

12345
Case Scenario 3

Scenario 4

Scenario 2

Scenario 1

All Non-Capture Thermoelectric PlantsFreshwater Needs for Thermoel ectric Generation, September 2008

61 Figure 54 illustrates the breakdown of Scenario 1 and a closer look at the other scenarios for Case 2. The bottom section of the blue bars are the additional water consumption required for the existing PC retrofits, 1.9 BGD. The top section of the blue bars is the additional water consumption required for th e carbon capture technolog ies of the new PC and IGCC capacity, 0.5 BGD. Therefore, Scenar io 1 would require at total of 2.4 BGD. Scenario 2 would include the 2.4 BGD plus an additional 0.7 BGD of water consumption for the new IGCC plants built to replace the power lost to the retrofits for a total 3.1 BGD. Scenario 3 is similar to Scenario 2 ex cept instead of IGCC plants built to make up the power loss, supercritical PC plants would be built. Th ese supercritical PC plants would require 1.6 BGD water consumption and combined with the Scenario 1 demand, would require a total 4.0 BGD. Scenario 4, ad ditional nuclear plants built to replace the power lost to the retrofits, would add 1.3 B GD to scenario1 for a total water consumption of 3.7 BGD.

Figure 54 - Additional Water Consumption of CO 2 Capture Scenarios – Case 2

0 1 2 3 4 5Water Consumption(BGD)

1234

Scenario New Nuclear Replacement Power New PC Replacement Power New IGCC Replacement Power
New PC and IGCC with CO2 Existing PC Retrofits with CO2

Figure 55 and Figure 56 show the water withdr awal and consumption for the five cases and three coal-fired scenarios with resp ect to just the coal-fired fleetFreshwater Needs for Thermoel ectric Generation, September 2008

62 Figure 55 - PC and IGCC Generation with Additional Water Withdrawal for PC and IGCC Carbon Capture Deployment for Year 2030 –

1 2 3 4 5 Scenario 2

Non CO2 Capture

0 20 40 60 80 100Water Withdrawal(BGD)

Case Non CO2 Capture
Scenario 1
Scenario 2
Scenario 3

Figure 56 - PC and IGCC Generation with A dditional Water Consumption for PC and IGCC Carbon Capture Deployment for Year 2030

1 2 3 4 5 S

c

e

n a r i o 3 S

c

e

n a r i o 2

Scenario 1

Non CO2 Capture 0 2 4 6 8Water Consumption(BGD)

Case

The results for the three scenarios for tota l water withdrawal and consumption for PC plants with scrubbers and IGCC plants with carbon capture technolog ies are presented in Table 11 and Table 12 respectively. The baseline va lues listed in the tables are used as a reference for non-capture PC plants w ith scrubbers and IGCC plants.Freshwater Needs for Thermoel ectric Generation, September 2008

63 Table 11 – Scenarios for Year 2030 Total Wat er Withdrawal for Scrubbed PC and IGCC with CO 2 Capture and No Capture Baseline Reference

Water Withdrawal (BGD) Scenario Case 1 Case 2 Case 3 Case 4 Case 5 No CO 2 Capture Baseline 76.9 66.1 66.0 65.8 56.2 1. No Water Based Generation Retrofit load not accounted for using water intensive generation types 80.5 69.7 69.2 68.5 59.8

2. IGCC Recirculating Additions Fixed Additions accounts for retrofit load 81.3 70.5 70.0 69.2 60.6

3. Supercritical Recirculating Additions Fixed Additions accounts for retrofit load 82.6 71.8 71.1 70.8 61.9

4. Nuclear Recirculating Additions Fixed Additions accounts for retrofit load 83.0 72.1 71.4 70.8 62.2

Table 12 – Scenarios for Year 2030 Total Wat er Consumption for Scrubbed PC and IGCC with CO 2 Capture and No Capture Baseline Reference

Water Consumption (BGD) Scenario Case 1 Case 2 Case 3 Case 4 Case 5 No CO 2 Capture Baseline 3.0 3.2 3.1 2.9 3.3 1. No Water Based Generation Retrofit load not accounted for using water intensive generation types 5.4 5.6 5.5 4.8 5.8

2. IGCC Recirculating Additions Fixed Additions accounts for retrofit load 6.1 6.3 6.1 5.3 6.4

3. Supercritical Recirculating Additions Fixed Additions accounts for retrofit load 7.0 7.2 6.9 6.0 7.3

4. Nuclear Recirculating Additions Fixed Additions accounts for retrofit load 6.7 7.0 6.7 6.0 7.1

Depending on the cases and scenarios for pl ant additions, deployi ng carbon capture technologies in PC plants with scrubbers and IGCC plants in the year 2030 would increase water withdrawal anywhere from 2.7 BGD to 6.0 BG D where the average increased water withdrawal for all scenario s and cases is 7%. The increase in water consumption could range from 1.9 BGD to 4.0 BGD and the aver age increased water consumption for all scenarios and cases is 103%.

Comparison of 2007 & 2008 Study Projections

The 2007 and 2008 water needs analyses evaluated the same five cases. The baseline thermoelectric water withdrawal (year 2005) for the 2008 analysis was approximately two-tenth of a percent lower than the 2007 analysis - 146.6 BGD for the 2007 analysis and 146.3 BGD for the 2008 analysis. Water co nsumption for the 2005 baseline year was identical for the 2007 and 2008 results, 3.7 B GD. The 2008 analysis shows lower waterFreshwater Needs for Thermoel ectric Generation, September 2008

64 withdrawal and consumption for all years and all five cases compared to the 2007 analysis. Table 13 presents the difference in water withdrawal and consumption for the 2008 update compared to the 2007 report at the national level. Table 14 shows the percent cha nges from the 2007 results.

Overall, there are many parameters that affected the results. The larg est factor to account for the decrease in overall thermoelectric water withdrawal and consumption this year is EIA’s decrease in thermoelectric capacity co mpared to the previous year. The EIA’s AEO 2008 forecast estimates U.S. thermoelect ric generating capacity will grow from approximately 700 GW in 2005 to 824 in 2030, compared to the AEO 2007 forecast which was 708.7 GW in 2005 to 861.7 GW in 2030; a 4% decrease by 2030 17 . The 2008 forecasts for coal and combined cycle capac ities are expected to increase by 2030 but less then the 2007 forecast. The forecasted capa city for other fossil steam and nuclear is higher for the AEO 2008, however the lowe r amount of coal and combined cycle capacity is greater and lowers the overall thermoelectric capac ity. The AEO 2008 data forecasts less thermoelectric additions and fewer retirements than AEO 2007.

At the regional level, WECC/CA showed d ecreases in water consumption for all five cases whereas the other regions showed an increase in water consumption. Combined cycle plants are the only thermoelectric additions to that region through 2030. The forecasted capacity factor of the combined cycle plants in the WECC/CA region is decreased by the year 2030. The forecasted ca pacity factor and the base year capacity factor are used to develop the F-factor, which accounts for the growth in generation. Further explanation of the F-factor is in Appendix B. The magnitude of the F-factor affects the water consumption of plants that have recirculation cooing systems. A lower F-factor reduces the amount of water consumed.

The 2008 report presented a higher amount of make up power for the parasitic loss due to the carbon capture retrofits (79.3 GW) compared to the 2007 report (72.7 GW). This is due to the change in the year that the carbon capture techno logy would be implemented. The 2007 report assumed that the implementation would st art in 2010 and the 2008 report assumes the year 2020. This additional ten years for the implementation increases the number of plants that would have to be retrofitted by 2030 for the analysis. However overall water withdrawal and consumption re quired for the 3 carbon capture scenarios is less then the 2007 report due to EIA’s decrease in PC and IGCC forecasted capacity.Freshwater Needs for Thermoel ectric Generation, September 2008

65 Table 13 - Results Comparison, Difference fr om 2007 vs. 2008 Wa ter Needs Analysis

The 2008 analysis show the same general tr ends among the 5 cases as seen in the 2007 analysis. For cases 2 though 5, withdrawal is exp ected to decline, and consumption for all 5 cases is expected to increase. Thes e results are consistent with current and anticipated regulations and industry practice, which favor the use of freshwater recirculating cooling systems that have lower withdrawal requirements, but higher consumption requirements, than once-through co oling systems. Case 5 provides the most extreme water consumption impacts. Conver ting a significant shar e of existing oncethrough freshwater power plants to recirc ulating freshwater pl ants reduces water withdrawal, but increases water consumption. Case 4 indicates that dry cooling could have a significant impact on water consumption; compared to Cases 1-3, which have an average consumption of 5 BGD, Case 4 results in an almost 4% decline, equivalent to more than 70 billion gallons per year.

Table 14 - Results Comparison, Percent Ch anges from 2007 Water Needs Analysis Percent Change from 2007 Results 2005 2010 2015 2020 2025 2030 Withdrawal -0.2% -1.2% -1.0% -1.1% -0.9% -1.1% Case 1 Consumption -0.4% -2.5% -4.5% -6.1% -9.1% -11.8% Withdrawal -0.2% -0.4% -1.1% -1.1% -1.1% -1.6% Case 2 Consumption -0.4% -2.8% -4.0% -5.6% -7.7% -9.5% Withdrawal -0.2% -0.4% -1.1% -1.1% -1.1% -1.6% Case 3 Consumption -0.4% -2.7% -4.0% -5.4% -7.6% -9.6% Withdrawal -0.2% -0.4% -1.1% -1.0% -1.0% -1.4% Case 4 Consumption -0.4% -2.5% -3.8% -5.0% -6.9% -8.3% Withdrawal -0.2% -0.4% -1.1% -1.1% -1.2% -1.8% Case 5 Consumption -0.4% -2.8% -4.1% -5.5% -7.5% -9.2% Difference Between 2007 and 2008 Results (BGD) 2005 2010 2015 2020 2025 2030 Withdrawal -0.3 -1.8 -1.4 -1.6 -1.4 -1.7 Case 1 Consumption 0.0 -0.1 -0.2 -0.3 -0.4 -0.6 Withdrawal -0.30 -0.61 -1.5 -1.5 -1.6 -2.2 Case 2 Consumption 0.0 -0.1 -0.2 -0.3 -0.4 -0.5 Withdrawal -0.30 -0.61 -1.5 -1.5 -1.5 -2.2 Case 3 Consumption 0.0 -0.1 -0.2 -0.2 -0.4 -0.5 Withdrawal -0.30 -0.6 -1.5 -1.4 -1.4 -2.0 Case 4 Consumption 0.0 -0.1 -0.2 -0.2 -0.3 -0.4 Withdrawal -0.305 -0.6 -1.5 -1.4 -1.4 -2.0 Case 5 Consumption 0.0 -0.1 -0.2 -0.3 -0.41 -0.6Freshwater Needs for Thermoel ectric Generation, September 2008

66 

### Conclusions Population shifts, increasing power demand, an d greater competition for water resources has heightened interest in the link between energy and wa ter. The EIA projects about a 22% increase in total genera ting capacity by 2030 compared to 2005. Of the 207 GW of new capacity projected to come on-line by 2030, more than 124 GW will be thermoelectric generation.

On a national basis, this analysis indicates that the potential impacts on future freshwater withdrawals to meet forecasted increases in electricity generati ng capacity would be relatively low, with most cases exhib iting a decrease in daily withdrawals.

To operate the 124 GW of new thermoelect ric generating capacity in 2030, excluding Case 1:

• Freshwater withdrawal requi rements will decrease by 5.0% to 23% compared to freshwater withdrawals in 2005

• Freshwater consumption in 2030 will in crease by 30.7% to as much as 49% compared to 2005

Similar trends in freshwater withdrawal a nd consumption are projected for the additional coal-based generating capacity that will come on line by 2030:

• Freshwater withdrawal requirements will range from a 17% decrease to an 1% increase

• Freshwater consumption requirements will increase ranging from 36% to a 55%

While thermoelectric water consumption could increase by as much as 55%, it is still relatively small compared to other sectors, specifically irrigation/agriculture as seen in Appendix A.

The regional component of the 2008 water ne eds analysis revealed some significant differences from the national averages, reflecting recent U.S. population shifts. Regions with strong population growth, such as the s outheast and southwest, exhibit high growth in water consumption requirements, while regions with minimal to modest population growth, such as the midwest and mid-Atla ntic, exhibit modest growth in water consumption requirements. EIA projects a 45% increase in thermoelectric capacity by 2030 for the western United States and a 27% in crease in the southeas t compared to the 18% increase nationally. These increases in pr ojected capacity will occur in regions of the United States that are challenged in term s of both current and future availability of freshwater. For example, consider Case 2, a pl ausible future cooling system scenario that assumes all capacity additions use freshwa ter and wet recirculating cooling.

National percent changes indicate between 2005 and 2030 (Case 2)

• water withdrawal will fall by 5%

• water consumption will rise by 40%Freshwater Needs for Thermoel ectric Generation, September 2008

67 Regional percent changes indica te between 2005 and 2030 (Case 2)

• Water withdrawal ranges from a 50% increase in Florida to a 24% decline in Texas

• Water consumption increases in all regions

o Biggest gains come in Florida (336 %), New York (207%), New England (93%), and the Northwest regions (80%)

The thermoelectric power generation sector w ill remain a considerable water consumer for the foreseeable future. While national water withdrawals are projected to decline slightly over the 25-year time period evaluate d in this analysis, the amount of water withdrawal is huge, on the orde r of 112 to 154 billion gallons per day. On a consumption basis, although the magnitude is much less than that for withdrawal, the trend is steadily upward, regardless of the case considered. National water consumption is expected to grow from 3.7 billion gallons per day in 2005 to between 4.7 and 5.5 billion gallons per day by 2030. In the face of growing competition for water resources – particularly in the arid West and Southwest, and in the expandi ng Southeast – regional and national efforts to reduce water withdrawal and consump tion for thermoelectric power plants are expected to intensify.

Assuming current carbon capture technologies ar e implemented at coal-fired PC plants in the future, an increased amount of water us age will to be required. EIA’s current forecasts show that coal-fired generation will play a large part in our Nation’s electric generation portfolio. The water use for the carb on capture section of th is analysis is a 1 st order view to get a general idea of how th e implementation of th ese technologies will affect the water withdrawal and consumpti on. Depending on the cases and scenarios for plant additions, deploying carbon capture technol ogies in PC plants with scrubbers and IGCC plants in the year 2030 would increase water withdr awal anywhere from 2.7 BGD to 6.0 BGD where the average increased water withdrawal for all scenarios and cases is 7%. The increase in water consumption co uld range from 1.9 BGD to 4.0 BGD and the average increased water consumption for all scenarios and cases is 103%. As seen in the past with other emission control technolog ies, R&D efforts will promote improved efficiencies with current technologies and develop new emerging technologies, therefore lowering the water demands.Freshwater Needs for Thermoel ectric Generation, September 2008

A-1 

### Appendix A Energy-Water Issues Supplemental Information

Competing Water Uses Concerns over limited water quantities are not restricted to thermoelectric generation. According to USGS, 346 billion gallons of freshwater were withdrawn per day in the United States in the year 2000. 4 The largest use, agricult ural irrigation, accounted for 40% of freshwater with drawn (see Figure A-1).

Figure A-1 - Percent of freshwater withdrawal by use category

U.S. Freshwater Withdrawal (2000)

Thermoelectric, 39% Public Supply, 13% Domestic, 1%

Irrigation, 40%

Livestock, 1%
Aquaculture, 1%

Industrial, 5% Mining, 1%

The second largest use, thermo electric generation, withdrew 136 billion gallons per day (BGD), followed by public supply, industrial uses, aquaculture, domestic use, mining, and livestock. Interestingly, thermoelectric generation withdrew the largest amount of saline water, 60 BGD (96% of all saline with drawn). Withdrawal of saline water (and other non-traditional waters) redu ces the strain on freshwater supplies and is one research area facilitated by the IEP program.

USGS estimates for freshwater consumption for the year 1995 (the most recent year for which this data is available) is presented in Figure A-2. 5 Freshwater consumption for thermoelectric purposes appears low (only 3%) when compared to other use categories (irrigation was responsible for 81% of wa ter consumed). However, even at 3% consumption, over 3 BGD were consumed. As a result of growing public pressures to withdraw less water, coupled with requireme nts under Section 316(b) of the Clean Water Act, consumption will likely increase significantly due to greater use of closed-loop cooling systems that consumes far more wa ter than once-through cooling systems due to evaporation losses.Freshwater Needs for Thermoel ectric Generation, September 2008

A-2 Figure A-2 - Percent of freshwater consumption by use category

U.S. Freshwater Consumption (1995)

Thermoelectric, 3% Mining, 1%
Industrial, 3%

Livestock, 3%

Irrigation, 81% Domestic, 6% Commercial, 1%

In addition to the water uses described above , increased value is being placed on instream freshwater uses, consisting mainly of habitat/species protection and recreational uses. In-stream uses will requ ire a minimum flow rate or depth to be maintained in water bodies.

Because freshwater supply is limited, choices will have to be made regarding withdrawal and consumption of this natural resource. Water availability and its withdrawal and consumption are top prioriti es on the public agenda in many nations throughout the world. It is likely that the issue will also filt er to the top of the U.S. public agenda in the near future. In water-stressed areas of the country, power plan ts will increasingly compete with other water users. Agriculture and public supply will most likely be the greatest competitors due to their large water w ithdrawal. As with all resources, tradeoffs will occur, and concerns will increasingly be raised over which use is more important: water for drinking and personal use, growing food, or energy production. Regulatory Impacts on Water Withdrawal and Consumption The power industry must comply with a vari ety of local, state a nd federal regulations pertaining to water acquisiti on, use, and quality. In c onsidering long-term water withdrawal and consumption pa tterns in the power sector, the cooling water intake structure regulations established under the Clean Water Act, Section 316(b) will likely have the greatest impact. Designed to protect aquatic life from inadvertently being killed by intake structures at power stations and certain manufacturing facilities, Section 316(b) requires EPA to ensure that the “location, design, construction and capacity of cooling water intake structures refl ect the best technology avai lable for minimizing adverse environmental impact.”

EPA divided its 316(b) rulemaking into three phases: Phase I, completed in late 2001, applies to new facilities; Phase II, comple ted in early 2004, applies to large existing power facilities; and Phase III, due to be finalized in 2006, applies to existing manufacturing facilities. Th e regulations establish perfor mance standards for cooling water intake structures based on impingement mortality and entrainment (IM&E) impacts. A minimum level of IM&E reductio n is required based on the type of waterFreshwater Needs for Thermoel ectric Generation, September 2008

A-3 body a given facility accesses for cooling wate r. Compliance with 316(b) is coordinated through the individual states’ NPDES (Nationa l Pollutant Discharge Elimination System) permitting program.

The largest design impact of 316(b) compliance is that most new power plants will have to use closed-loop, recirculati ng cooling systems or dry (air-cooled) systems. Open-loop systems are strongly discouraged unless th e permit applicant can demonstrate that alternative IM&E measures can provide a re duction level comparable to that achieved through closed-loop cooling or that the compliance costs, air quality impacts, and/or energy generation impacts would outweigh the IM&E benefits and justify an open-loop system. Because 316(b) portends a greater reliance on closed-loop cooling systems, water withdrawal and consumption patterns for the thermoelectric power sector are destined to change over time. Even accounting for significant thermoelectric capacity additions, water withdrawal levels will likely remain relatively constant. Water consumption, on the other hand, is expected to increase substantially since closed-loop cooling systems consume more water, due to evaporation, than open-loop systems.

Existing and future air quality regulations will also affect water withdrawal and consumption patterns, although to a lesser exte nt than cooling water regulations. Tighter emission levels for sulfur dioxide, for example, have sparked a mini-boom in the flue gas desulfurization (FGD) market. The size of the U.S. FGD market is expected to increase by more than 100,000 megawatts (MW) over th e next 10 years. Although FGD water requirements are a fraction of those required for cooling purposes, FGD units require a significant amount of water to produce and handle the various process streams (limestone slurry, scrubber sludge, etc.). Makeup water requirements for the FGD island at a nominal 550 MW subcritical coal-fired pow er plant are about 570 gpm, versus about 9,500 gpm for cooling water makeup. 18 Nonetheless, the additional FGD systems coming online within the next decade will pl ace a greater strain on water supplies. Notably, semi-dry flue gas desulfurization sy stems are available that substantially reduce water requirements for SO 2 control, and these systems are in commercial application at numerous plants, many in arid environments.

Several other regulatory actions warrant atte ntion because of their potential impact on water withdrawal and consumption. Under section 303(d) of the 1972 Clean Water Act, states, territories, and authori zed tribes are required to deve lop a list of impaired waters not meeting water quality standards and th en establish total maximum daily loads (TMDL) for these waters. A TMDL specifie s the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and allocates pollutant loadings among point and nonpoint pollutant sources. TMDL requirements could potentially constrain a power plant’s ability to discharge cooling water, as well as trace metals and other pollutants from flue-gas cleanup byproducts, into a water body if the water body is impaired. The power plant may th en be required to seek an alternate water source or install additional water treatment equipment.

The current debate over global clim ate change and carbon dioxide (CO 2 ) emissions could also potentially impact the water resource situation. If power plants are ultimatelyFreshwater Needs for Thermoel ectric Generation, September 2008

A-4 required to implement carbon separation and sequestration technologies to comply with future regulations, additiona l water may be needed for certain process steps and groundwater could be impacted by CO 2 sequestration (in a manner similar to produced water from oil and gas recovery applications). On the ot her hand, water could potentially be recovered from the CO 2 stream prior to dry pumping for sequestration or reclaimed from produced waters due to underground displacement. A detailed analysis would be required to delineate the net water withdr awal and consumption associated with CO 2 separation and sequestration and is outside the scope of this study.

Legislative Activities The Energy Policy Act of 2005 (Title IX, Subtitle G

− Science, Section 979) directs the DOE to address energy-water nexus issues and assess the effectiveness of existing Federal programs to address energy-water rela ted issues. The direction is for a program of research, development, demonstration, and commercial applicat ion to: 1) address energy-related issues associated with provi sion of adequate management, and efficient use of water; 2) address water-related issues associated with the provision of adequate supplies, optimal management, and effici ent use of energy; and 3) assess the effectiveness of existing programs within the Department and other Federal agencies to address these energy and water related issues.

An amendment to the Energy Policy Act, the Energy-Water Efficiency and Supply Technology Bill, was originally introduced in 2004 and has gone through two revisions. The current version of the bill would allocate $5 million for the first year and “such sums as are necessary for each fiscal year thereafte r.” The bill would instruct the Secretary of Energy to “establish a national program for th e research, development, demonstration, and commercial application of economically viable and cost-effective water supply technologies.”

Drought Conditions A Government Accountability Office (GAO) report 19 prepared in 2003 addressed the issue of freshwater supply at the state le vel. The report indicated that under normal rainfall conditions, state water managers in 36 states anticipated shortages in localities, regions, or even statewide in the next 10 ye ars (2003 – 2013). The re port goes on to say that “drought conditions will exa cerbate shortage impacts.”

During the summer of 2005, a joint effort betw een the Department of the Interior (DOI) and the Department of Agriculture (USDA) created Interagency Drought Action Teams to coordinate relief efforts in communitie s in western states facing droughts. A DOI report 20 about the action teams quotes Secretary (of the Interior) Norton, “Much of the Pacific Northwest has been hard hit by drought this year.”

Power Generation Facility Siting Concern about water supply, expressed by state regulators, local decision-makers, and the general public, is already impacting power projects across the United States. For example, in March 2006, an Idaho state House committee unanimously approved a two-Freshwater Needs for Thermoel ectric Generation, September 2008

A-5 year moratorium on construction of coal-f ired power plants in the state based on environmental and water supply concerns. 21 Arizona recently rejected permitting for a proposed power plant because of concerns about how much water it would withdraw from a local aquifer. 22 In early 2005, Governor Mike Rounds of South Dakota called for a summit to discuss drought-induced low flow s on the Missouri River and the impacts on irrigation, drinking-water sy stems, and power plants. 23 A coal-fired power plant to be built in Wisconsin on Lake Michigan has b een under attack from environmental groups because of potential effects of the facility’s cooling-water-i ntake structures on aquatic life. 24 In February 2006, Diné Power Authority reached an agreement with the Navajo Nation to pay $1,000 per acre foot and a guaranteed minimum total of $3 million for water for its proposed Dese rt Rock Energy Project. 25 In an articl e discussing a 1,200 MW proposed plant in Nevada, opposition to th e plant stated, “There’s no way Washoe County has the luxury anymore to have a fossi l-fuel plant site in the county with the water issues we now have. It’s too importa nt for the county’s economic health to allow water to be blown up in th e air in a cooling tower.” 26Freshwater Needs for Thermoel ectric Generation, September 2008

B-1 

### Appendix B Water Needs Analysis Methodology

The purpose of this analysis is to update a 2004 Nationa l Energy Technology Laboratory (NETL) study to estimate freshw ater needs to meet future year thermoelectric generation capacity requirements. The 2006 and 2007 anal yses use a more detailed analytical approach and incorporate data and pr ojections from the Energy Information Administration’s Annual Energy Outlook yearly publications. Table B-1 summarizes the specific items that are updated in the 2006/200 7 Water Needs Analyses. The additional level of detail and resolution included in the 2006/2007 analyses required a modified methodology from that used in the 2004 analysis.

Table B-1 - U.S. Power Generation Industry Water Withdrawal and Use Anal ysis – Comparison of Assumptions and Methodologies Item 2004 Analysis 2006/2007 Analysis Capacity/Generation Projections AEO 2004 AEO 2006/2007

Geographical Breakdown National National and NERC region

Cooling Water Source Breakdown Freshwater and Saline Freshwater and Saline

Cooling Water System Type Once-through and wet recirculating Once-through and recirculating (dry, wet, and cooling pond)

Generation Type Breakdown Total thermoelectric and coal Total thermoelectric and coal, nuclear, non-coal steam, and natural gas combined cycle
Final Year of Projection 2025 2030

Cases Six cases representing upper and lower bounds Five cases with conservative assumptions Water Use Scaling Factors – Geographic Coverage National NERC region with adjustment for capacity factor increase
Water Use Scaling Factors – Coal Plant Design Not included Boiler type – subcritical or supercritical FGD type – wet, dry, or none

Additional Water Uses for CO 2 Capture Plants Not included 2006 Analysis – Not included 2007 Analysis – Included for PC and IGCC Plants

Figure B-1 provides a flowch art depiction of the methodology used to conduct the analysis. The five-step approach represents a refined and more robust methodology than that used in the 2004 Water Needs Analysis. Ea ch step in the process is described below.Freshwater Needs for Thermoel ectric Generation, September 2008

B-2 Figure B-1 - Methodology for the 2006/2007 Water Needs Analysis

Develop model plants to represent existingthermoelectric fleet Calculate water withdrawal and consumption factors Quality control and model validation Develop future cases to evaluate Calculate regional withdrawal and consumption to 2030 Step 1 Step 2 Step 3 Step 4 Step 5

Step 1: Develop model plants To obtain the resolution desired for this analysis, water withdrawal and consumption factors were determined for a large number of plant configurati ons, based on location, generation type, cooling water source, cooli ng system type, and where applicable, boiler type and type of flue gas de sulfurization (FGD) system. Th e existing thermoelectric fleet was segregated into numerous configurations , called “model plants” using data contained in several sources: the NETL Coal Plan t Database, EIA-767, and EIA-860. Water withdrawal and consumption factors were calculated for each model plant using the available data and then us ed in conjunction with proj ections from AEO 2006/2007 to provide an estimate of future water withdr awal and consumption for various cases.

The model plant derivation pro cess is detailed below.

NERC Regions Cooling water needs will vary by region due to climatic variations and availability of cooling water. Performing the water needs analysis on a regional level, therefore, provides a more accurate estimate of cooling wa ter trends than a higher-level analysis. To accomplish this, the 13 NERC regions (excluding Alaska and Hawaii) were integrated into the NETL Coal Plant Database from the EIA-860 database.

Thermoelectric Generation Type Water withdrawal and consumption factors were determined for thermoelectric power plants: coal, nuclear, oil, natu ral gas and the steam portion of gas-fired combined cycles. However, more detailed effort was expended in determining water factors for coal-fired power plants. The analysis doe not include non-thermoelectri c plants such as combustion turbines, renewable generations, etc.

Individual water use estimates were de veloped for the following thermoelectric generation types:

i. Coal ii. Nuclear iii. Non-Coal Fossil iv. Combined CycleFreshwater Needs for Thermoel ectric Generation, September 2008

B-3 Model plants for coal in each NERC re gion were developed using the following hierarchy:

Cooling Water Type (Freshwater/Saline)

↓

Cooling Water System Type (Once-Thr ough, Wet Recirculating, Dry Recirculating, Cooling Ponds)

↓

Boiler Type (Subcritical, Supercritical)

↓

FGD Type (Wet, Dry, None)

Using this hierarchy, a total of 30 model pl ants are possible for coal in each region e :

1. Freshwater, once-throug h, subcritical, wet FGD 2. Freshwater, once-throug h, subcritical, dry FGD 3. Freshwater, once-throug h, subcritical, no FGD 4. Freshwater, once-through, supercritical, wet FGD 5. Freshwater, once-through, supercritical, dry FGD 6. Freshwater, once-throug h, supercritical, no FGD 7. Freshwater, recirculatin g, subcritical, wet FGD 8. Freshwater, recirculatin g, subcritical, dry FGD 9. Freshwater, recirculatin g, subcritical, no FGD 10. Freshwater, recirculating, supercritical, wet FGD 11. Freshwater, recirculating, supercritical, dry FGD 12. Freshwater, recirculating, supercritical, no FGD 13. Freshwater, cooling pon d, subcritical, wet FGD 14. Freshwater, cooling pon d, subcritical, dry FGD 15. Freshwater, cooling pon d, subcritical, no FGD 16. Freshwater, cooling pond, supercritical, wet FGD 17. Freshwater, cooling pond, supercritical, dry FGD 18. Freshwater, cooling pon d, supercritical, no FGD 19. Saline, once-through, subcritical, wet FGD 20. Saline, once-through, subcritical, dry FGD

e According to the hierarchy presented, 36 model plant combinations are possible. Six of these combinations would be configured with saline cooling ponds. Such a cooling water source is technically impractical and, therefore, not included in this analysis.Freshwater Needs for Thermoel ectric Generation, September 2008

B-4 21. Saline, once-through, subcritical, no FGD 22. Saline, once-through, supercritical, wet FGD 23. Saline, once-through, supercritical, dry FGD 24. Saline, once-through, supercritical, no FGD 25. Saline, recirculating, subcritical, wet FGD 26. Saline, recirculating, subcritical, dry FGD 27. Saline, recirculating, subcritical, no FGD 28. Saline, recirculating, supercritical, wet FGD 29. Saline, recirculating, supercritical, dry FGD 30. Saline, recirculating, supercritical, no FGD

Similar model plants were developed for nuc lear, non-coal fossil, and combined cycle, but only broken down by cooling water type (freshwater vs. saline) and cooling water system type (once-through, recirculating, cooling pond).

Step 2: Calculate water withdr awal and consumption factors For each model plant defined in Step 1, water withdrawal and consumption factors were calculated using the data sources outlined above.

Coal For coal, the water withdrawal and consumption factors were based on the sum of three components: 1) boiler make-up water; 2) FGD make-up water; and 3) cooling water.

The boiler make-up water component at a co al plant depends on the type of boiler – either subcritical or supercri tical. The boiler make-up water factors were calculated using water balance data contained in Parsons ’ “Power Plant Water Consumption Study” conducted for NETL in August 2005. Separate values were determined for subcritical and supercritical plant configur ations, but the values were fixed for all regions, water source, cooling type, and FGD type.

The FGD make-up water component depends on the type of FGD syst em – either wet or dry. Dry FGD systems require much less water than wet FGD systems, for example, so different factors must be used. The FGD ma ke-up water factors were calculated using material balance data contained in Ca rnegie Mellon University’s Integrated Environmental Control Model (I ECM). Separate values were determined for subcritical and supercritical plant configur ations, but the values were fixed for all regions, water source, and cooling type.

The cooling water component for each mode l plant was calculated by compiling data from the NETL Coal Power Plant Database and EIA-860 for wate r withdrawal, water consumption, and summer capacity. Average water withdrawal (gal/hr), average water consumption (gal/hr), and summer capacity we re used to calculate average withdrawal and consumption scaling factors (gal/kWh) for each model plant in each of the NERC regions. The power plant capacity data cont ained in the NETL database consists ofFreshwater Needs for Thermoel ectric Generation, September 2008

B-5 nameplate MW capacity taken from the EIA-767 report. However, the AEO projections are based on summer capacity. Therefore, summer capacity (MW) data was obtained from the EIA-860 report to calculate the sc aling factors. The following methodology was used to calculate the average cooling water withdrawal and consumption factors for each type of cooling water system:

o Once-through systems: To maximize plant efficiency during partial load operation, power plant operators normally maintain cooling water flow through the condenser at full load design rates. Therefore, the cooli ng water withdrawal rate for a once-through cooling water system is dependent on plant capacity (kW) and independent of plant electrical gene ration (kWh). For this reason, the water usage factors for once-through systems were determined by dividing the sum of the average withdrawal or consumption ra te by the sum of the generator summer capacity.

Withdrawal Factor (gal/kWh) = Σ Average Withdrawal (gal/h) / Σ Capacity (kW) (1a)

Consumption Factor (gal/kWh) = Σ Average Consumption (gal/h) / Σ Capacity (kW) (1b)

o Wet Recirculating Systems: Similar to once-through systems, to maximize plant efficiency during partial load operation, power plant operators normally maintain cooling water flow through the condenser a nd across the cooling to wer at full load design rates. However, as more power is produced, the heat load to the cooling tower increases, resulting in greater evaporative losses and blowdown and consequently, higher water withdrawal requirements. Therefore, water withdrawal and consumption are inde pendent of plant capacity (kW) and dependent on plant electrical generation (k Wh) in wet recirculating systems. For this reason, the water usage factors for wet recirculating cooling systems were adjusted for each year of the analysis by applying a capacity factor ratio, F, to account for the growth in generation.

Withdrawal Factor (gal/kWh) = F x Σ Average Withdrawal (gal/h) / Σ Capacity (kW) (2a)

Consumption Factor (gal/kWh) = F x Σ Average Consumption (gal/h) / Σ Capacity (kW) (2b)

Where:

F = Ratio of capacity factor in year X to capacity factor in baseline year 2003

o Cooling Ponds : EIA-767 considers cooling ponds to be a type of wet recirculating cooling system since heat loss occurs through evaporative loss. However, cooling water flow rates for a cooling pond are more similar to oncethrough than wet recirculating systems. Therefore, for this study, water usage factors were calculated using the same formula as for once-through systems.Freshwater Needs for Thermoel ectric Generation, September 2008

B-6 o Dry Recirculating Systems : For dry recirculating systems, the cooling water withdrawal and consumption fact ors are both assumed to be zero.

Non-Coal Plants Nuclear, oil steam, gas steam, and natural gas combined-cycle plants were classified according to NERC region, cooling water source (fresh or saline), and cooling water system (recirculating or once-th rough). Water usage factors for each plant classification were determined using equations 1a, 1b, 2a , and 2b, depending on type of cooling water system.

In calculating water withdrawal and consump tion quantities for combined-cycle plants, an adjustment was made to account for the f act that the gas turbine portion of the plant does not require cooling water. The design capacity of the gas turbine portion of a combined-cycle facility is typically twice that of the steam turbine portion; in other words, two-thirds of a combined-cycle plant’s total output is derived from the gas turbine(s). Therefore, only about one-third of the plan t output is used for steam generation, with its associated water requireme nts. For this analysis, water withdrawal and consumption factors were applied to only one-third of the comb ined-cycle capacity.

Step 3: Quality Control and Model Validation Step 3 represents just one of several efforts designed to en sure quality control for the analysis. Because models, by definition, ar e simplified representations of reality, absolute model accuracy is impossible to guarantee in any situation. It is important, however, to have procedures in place to ensure that output from a given analysis is consistent with reality and reasonable exp ectations. Several step s were taken for the water needs analysis to achieve this objective.

The water withdrawal and consumption fact ors that were used in the model were obtained through a rigorous evaluation of da ta collected by the Energy Information Administration, primarily forms EIA-767 and EI A-860. Data presented on these forms is assumed to accurately represent conditions at a particular power plant. A variety of reasons, however, could account for errors and discrepancies in the data: lack of understanding of the form’s directions, data entered in the wrong place s, inaccurate data entry, improperly aggregat ed data, and others.

The calculated water withdrawal and cons umption factors for a given categorical breakdown (e.g., NERC region) should fall w ithin a limited range based on generation type and cooling type. If the dataset in th at categorical breakdown was too small, data outliers could have disproportionately impacted the results. While it is impossible to eliminate all such errors, the data was carefu lly vetted to ensure quality data points were used. Certain entries were modified or discarded based on accompanying information and engineering judgment. For example, if a power plant was designated as a oncethrough facility, but reported cooling water wi thdrawal and consumption quantities that clearly identify it as a recircul ating facility, the plant was re -classified as a recirculating facility.Freshwater Needs for Thermoel ectric Generation, September 2008

B-7 To ensure that the estimates generated by the water needs analysis model were reasonable, power generation data from 1995 was obtained and inserted into the model. The calculated water withdrawal and consumption values for thermoelectric generation were then compared with U.S. Geologic Se rvice estimates for water withdrawal and consumption for 1995.

Step 4: Develop Future Cases Table B-2 summarizes the cases evaluated in the original 2004 analysis and the 2006/2007 analysis. The effects of emerging issu es, particularly the impact of the Clean Water Act 316(b) regulations, f were incorporated into the selection of the 2006/2007 cases. Comments are provided with each of the cases to assess their likelihood and justify the chosen cases. Five cases were included in the 2006/2007 Water Needs Analysis, one reflecting status quo conditions, tw o reflecting varying levels of regulations regarding cooling water source, one inco rporating dry cooling, and one reflecting regulatory pressures to convert existing once- through capacity to reci rculating capacity.

To determine total water withdrawal and consumption requirements for thermoelectric generation in future years, new capacity addi tions and existing capacity retirements were factored into the analysis. As noted in the table, retirements were modeled based on current source withdrawals; in other words, freshwater and saline units were retired from service in proportion to their current contribu tions to total installed capacity, which is thought to more accurately reflect industry beha vior. Units recently retired and/or placed in cold reserve have been removed from service due to age and operational cost constraints; cooling water source has played a minimal or nonexistent role. Future capacity retirement decisions, therefore, wi ll likely remain more dependent on age and operational costs than cooli ng water source, and should re flect current proportions of freshwater and saline water facilities.

Retired capacity in a given NERC region was broken down by generation type, water source, cooling type, and, wher e applicable, boiler and F GD type, based on the current proportion of capacity for each specific combination. The corresponding water withdrawal and consumption factors were th en applied to the retired capacity to determine how much water must be deducte d from the withdrawal and consumption totals.

In modeling capacity additions, it was necessary to consider the different thermoelectric generation types. A variety of model plants were added based on the case assumptions. Expected capacity additions in a given region in a given year, as projected by AEO 2006/2007, were apportioned into these model plant categories. Each model plant will

f The Clean Water Act’s 316(b) regulations require th e U.S. Environmental Protection Agency to ensure that cooling water intake structures at power plan ts and other manufacturing facilities reflect the best technology available for minimizing adverse envir onmental impact. The practical impact of these regulations is that most new power plants will have to incorporate closed-loop, recirculating cooling systems, which overwhelming ly rely on freshwater.Freshwater Needs for Thermoel ectric Generation, September 2008

B-8 have an associated water withdrawal a nd consumption factor. The corresponding capacity (kW) for each model plant categor y was used with the withdrawal and consumption factors to calculate increm ental water withdrawal and consumption.

The model plants for the five cases are listed in Table B-3. Because of the resolution provided in this analysis for coal-fired power plants, more model plants were developed for coal than for the other generation types. Several notes are in or der regarding the coal model plants:

• For pulverized coal plants, new additions ar e expected to favor supercritical boiler technology. Nationwide, the current split between subcritical and supercritical boiler technology capacity is 73% subcritic al/27% supercritical , reflecting greater industry experience and familiarity with subcritical technology. Pressure from several sources – environmental entities, state utility commissions, the threat of CO 2 regulations – is increasin g utility interest in supe rcritical boile r technology. A majority of the coal-fir ed power plants currently under construction or planned will rely on supercritical boiler technology. In selecting model coal plants for new additions, therefore, a 75% supercri tical/25% subcritical split was employed. See Appendix B for further information.

• For coal-fired power plants equipped w ith flue gas desulfurization equipment, water withdrawal and consumption rate s can exhibit relati vely significant differences based on whether the FGD is a wet or dry system. Since all new pulverized coal-fired power plants will need FGD systems to comply with emission regulations, future capacity addi tions must be apportioned by FGD type. Since emission regulations do not dict ate technology selec tion, the analysis apportions FGD type to new capacity addi tions based on the existing split in the coal-fired power fleet (by summer capacity), which is 90% wet/10% dry.

• The Annual Energy Outlook assumes that a portion of new coal-fired capacity will utilize integrated gasification combin ed-cycle (IGCC) technology. The water requirements for IGCC facilities differ from those at pulverized coal facilities. While both require cooling water, IGCC requires substantially less since a large fraction of the output from an IGCC plant is produced from the combustion turbines, which require minimal water. Moreover, since IGCC relies on water for significant process (non-cooli ng) use, it is unlikely that a saline water source would be desirable. The model IGCC coal plant, therefore, is restricted to freshwater use.

As discussed above, model plants for the non-coal thermoelectric generation capacity – nuclear, oil steam, gas steam, and natural ga s combined cycle – were broken down by water source (fresh or saline) and cooling wa ter type (once-through or wet recirculating) based on data from the EIA-767 and EIA-860 da tabases. Two model plants account for all likely new non-coal thermoelectric additions : a plant using a freshwater recirculating system and a plant using a saline once-through system. For Case 4, an additional model plant with dry cooling is included for bot h coal and non-coal generation types.Freshwater Needs for Thermoel ectric Generation, September 2008

B-9 Table B-2 - Case Selection, 2004 vs. 2006/2007 2004 Water Needs Analysis Case description Comments Case 1: All additions and retirements occur at facilities using freshwater. Reasonable. While the vast majority of new additions will use freshwater due to 316(b) regulations, it is unlikely that the majority of retirements will be from freshwater facilities. Retirement decisions will depend more on age and operational costs than on cooling water source. Case 2: Additions and retirements are proportional to current source withdrawals (70% freshwater/30% saline). Reasonable. As discussed for Case 1, retirement decisions will depend on age and operational costs, which will likely mirror the proportional split between freshwater and saline. For additions, however, 316(b) regulations will likely lead to a higher proportion of freshwater facilities since saline water is incompatible with wet recirculation systems. Case 3: All additions and retirements occur at facilities using saline water. Unlikely. Due to 316(b) regulations, saline water will likely account for a significantly smaller percentage of new additions. Retirements may slightly favor saline, but decision will depend more on age and operational costs. Case 4: Additions o ccur at freshwater facilities, while retirements occur at saline facilities. Reasonable. Although retiremen ts are likely to be more proportional to current source withdrawals, as discussed above.

Case 5: Additions occur at saline facilities, while retirements occur at freshwater facilities. Extremely unlikely. 316(b) regulations will make saline a difficult choice for additions. No regulatory or operational trends indicate that retiremen ts would favor freshwater.Case 6: All retired coal units use oncethrough cooling and are repowered using the existing once-through system. Additions reduced by the repowered units. Unlikely. Via repowering, units would be subject to new source regulations, which favor recirculating systems and the use of freshwater.

2006/2007 Water Needs Analysis Case Description Rationale Case 1: Additions and retirements proportional to current water source and type of cooling system. Status quo scenario case. Assu mes additions and retirements follow current trends.

Case 2: All additions use freshwater and wet recirculating cooling, while retirements are proportional to current water source and cooling system. Regulatory-driven case. Assumes 316(b) and future regulations dictate the use of recirculatin g systems for all new capacity. Retirement decisions hinge on age and operational costs rather than water source and type of cooling system. Case 3: 90% of additions use freshwater and wet recirculating cooling, and 10% of additions use saline water and once-through cooling, while retirements are proportional to current water source and cooling system. Regulatory-light case. New additions favor the use of freshwater recirculating systems, but some saline capacity is permitted. Retirement decisions remain tied to age and operational costs, tracking current source withdrawals.

Case 4: 25% of additions use dry cooling and 75% of additions use freshwater and wet recirculating cooling. Retirements are proportional to current water source and cooling system. Dry cooling case. Regulatory an d public pressures result in significant market penetration of dry cooling technology. Retirement decisions remain tied to age and operational costs, tracking current source withdrawals.

Case 5: Additions use freshwater and wet recirculating cooling, while Conversion case. Same as Case 2, except regulatory and public pressures compel state agencies to dictate the conversion of aFreshwater Needs for Thermoel ectric Generation, September 2008

B-10 retirements are proportional to current water source and cooling system. 5% of existing freshwater once-through cooling capacity retrofitted with wet recirculating cooling every 5 years starting in 2010. significant amount of existing freshwater once-through cooling systems to wet recirculating.

Table B-3 - Model Plants for New Capacity Additions Case 1 Coal • Pulverized coal, freshwater, recirculating cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Pulverized coal, saline water, once-through cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Integrated gasification combined-c ycle, freshwater, recirculating Nuclear • Freshwater, recirculating cooling system

• Saline water, once-through cooling system Non-coal fossil • Freshwater, recirculating cooling system

• Saline water, once-through cooling system Case 2 Coal • Pulverized coal, freshwater, recirculating cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Integrated gasification combined-c ycle, freshwater, recirculating Nuclear • Freshwater, recirculating cooling system Non-coal fossil • Freshwater, recirculating cooling system Case 3 Coal • Pulverized coal, freshwater, recirculating cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Pulverized coal, saline water, once-through cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Integrated gasification combined-c ycle, freshwater, recirculating Nuclear • Freshwater, recirculating cooling system

• Saline water, once-through cooling system Non-coal fossil • Freshwater, recirculating cooling system

• Saline water, once-through cooling system Case 4 Coal • Pulverized coal, freshwater, r ecirculating cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Pulverized coal, freshwate r, dry cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Integrated gasification combined-c ycle, freshwater, recirculating

• Integrated gasification combined-cycle, dry cooling system Nuclear • Freshwater, recirculating cooling system

• Dry cooling systemFreshwater Needs for Thermoel ectric Generation, September 2008

B-11 Non-coal fossil • Freshwater, recirculating cooling system

• Dry cooling system Case 5 Coal • Pulverized coal, freshwater, r ecirculating cooling system

o 75% supercritical/25% subcritical

o Wet FGD/dry FGD based on existing split

• Integrated gasification combined-c ycle, freshwater, recirculating Nuclear • Freshwater, recirculating cooling system Non-coal fossil • Freshwater, recirculating cooling system

Step 5: Calculate regional wi thdrawal and consumption to 2030 Step 5 integrates the water withdrawal and c onsumption factors calculated in Step 2 with the various cases defined in Step 4 to asse ss the regional and national impacts on water withdrawal and cons umption out to 2030.

The Annual Energy Outlook provides projections of future electricity generating capacity by year, by generation type and by NERC regi on. Apportioning this capacity among the chosen model plants for a given case an d then applying the wa ter withdrawal and consumption factors enables one to estimate wa ter withdrawal and consumption trends.

For a given case in a given region, the cap acity additions and retirements projected by AEO 2006/2007 were first divided between fres hwater and saline water based on the source withdrawal split for each technology t ype (coal, nuclear, non-coal fossil), as determined using existing fleet data. The additions and retirements were further apportioned among cooling water system type (once-through, recircul ating), again using existing fleet splits. For nuclear and non -coal fossil, the water withdrawal and consumption factors determined in Step 2 we re then applied to the resulting capacity amounts to calculate water withdrawal and consumption totals.

For coal, further segregation was necessary before performing the calculations. The additions and retirements were further appor tioned by technology type (supercritical and subcritical boilers). Retirements were divi ded based on the existing fleet split between supercritical and subcritical technology. Additions were di vided between supercritical and subcritical boilers at a 75/25 ratio to re flect a growing preference for supercritical technology, as described above in Step 4 and in Appendix C. The additions also must accommodate new IGCC plants; AEO projections for IGCC were used to apportion capacity amounts by region. Finally, coal reti rements and additions were apportioned by FGD type (wet, dry, none) using existing fleet data. The water withdrawal and consumption values determined in Step 2 were applied to the segregated capacity quantities determined in Step 5 to calculat e water withdrawal a nd consumption totals.

The calculations were a result of summing the re sults for each model plant in each region. The following is an example formula to calculate water withdrawal that was used for a model plant:Freshwater Needs for Thermoel ectric Generation, September 2008

B-12 Water Withdrawal (gal/hr) = A x B x C (3)

Where: A = Total regional capacity, kW B = Proportion of capacity assigned to model plant, %/100 C = Capacity factor-weighted water use scaling factor for model plant, gal/kWhFreshwater Needs for Thermoel ectric Generation, September 2008

C-1 

### Appendix C Future Coal-Fired Powe r Plant Boiler Type Supercritical versus Subcritical

The water analysis uses different water use scaling factors for coal-fired power plants based on boiler type. A supe rcritical boiler – operating at steam conditions above the critical point – is more efficient and theref ore requires less cooling water flow than a subcritical boiler for an equivalent amount of electrical generation output. The critical point represents the highest te mperature and pressure at which a substance can exist as a vapor and liquid in equilibrium. The critical point for water is 3200 psia and 705°F. Today’s supercritical boilers operate at st eam conditions of appr oximately 3500 psia and 1000°F compared to subcritical boilers that operate at appr oximately 2400 psia or less and 1000°F.

Table C-1 presents a summary of the breakdo wn by boiler type for currently operating U.S. coal-fired power plants according to data taken from Platt’s UDI Power Plant Database. The current boiler type breakdow n by MW capacity is 27 % supercritical and 73% subcritical. It should also be noted that supercritical boilers tend to be significantly larger in capacity. The average size of supe rcritical boilers is 743 MW compared to 234 MW for subcritical boilers.

Table C-1 – Boiler Type for Existing Plants

Operating Plants Total Supercritical Subcritical No. Units 1,136 117 1,019 Total Capacity, MW 325,651 86,903 238,748 Average Unit Capacity, MW 287 743 234 % Total Capacity Base 27% 73%

Table C-2 presents a similar summary by boiler type for coal-fired power plants either under construction or planned also taken from Platt’s UDI Power Plant Database. However, not all of the plants reported boiler type. For those plants that boiler type is reported, the breakdown by capacity is 55% supercritical and 45% subcritical. Similar to the currently operating plants, the average size of supercritical plants is 719 MW compared to 312 MW for subcritical plants . Since it appears that plant capacity correlates fairly well with boiler type, the unreported plants are segregated into two plant sizes – greater than or equal to 500 MW (87%) and less than 500 MW (13%).Freshwater Needs for Thermoel ectric Generation, September 2008

C-2 Table C-2 – Boiler Type for Future Plants – As Reported Boiler Type Reported Boiler Type Not Reported Plants Under Construction or Planned Total Total Supercritical Subcritical Total ≥ 500 MW < 500 MW No. Units 86 49 17 32 37 26 11 Total Capacity, MW 42,835 22,203 12,225 9,978 20,632 17,887 2,745 Average Capacity, MW 498 453 719 312 558 688 250 % Total Capacity 55% 45% 87% 13%

Based on the boiler type data in Table C-1 and reported boiler type data in Table C-2, it is apparent that plant capacity correlates fair ly well with boiler type. As a result, the unreported plants in Table C- 2 that were segregated by plant capacity can also be categorized by boiler type. Plants with a capa city greater than or equal to 500 MW are assumed to be supercritical and those with a cap acity less than 500 MW are assumed to be subcritical. Table C-3 pr esents the result of this categorization by combining the reported and unreported plant data from Table C-2. Therefore, future coal-fired plant capacity is assumed to be split as 75% supe rcritical and 25% subcritical for the water analysis.

Table C-3 – Boiler Type for Future Plants - Combined Plants Under Construction or Planned Total Supercritical Subcritical No. Units 86 43 43 Total Capacity, MW 42,835 30,112 12,723 Average Capacity, MW 498 700 296 % Total Capacity 70% 30%Freshwater Needs for Thermoel ectric Generation, September 2008

D-1 

### Appendix D Water Withdrawal and Consumption Factors

Table D-1 – National Average Withdrawal and Consumption Factors for Model Coal Plants

Model Plant Withdrawal Factor (gal/kWh) Consumption Factor (gal/kWh)
Freshwater, Once-Through, Subcritical, Wet FGD 27.113 0.138 Freshwater, Once-Through, Subcritical, Dry FGD 27.088 0.113 Freshwater, Once-Through, Subcritical, No FGD 27.046 0.071 Freshwater, Once-Through, Supercritical, Wet FGD 22.611 0.124 Freshwater, Once-Through, Supercritical, Dry FGD 22.590 0.103 Freshwater, Once-Through, Supercritical, No FGD 22.551 0.064

Freshwater, Recirculating, Subcritical, Wet FGD 0.531 0.462 Freshwater, Recirculating, Subcritical, Dry FGD 0.506 0.437 Freshwater, Recirculating, Subcritical, No FGD 0.463 0.394 Freshwater, Recirculating, Supercritical, Wet FGD 0.669 0.518 Freshwater, Recirculating, Supercritical, Dry FGD 0.648 0.496 Freshwater, Recirculating, Supercritical, No FGD 0.609 0.458 Freshwater, Cooling Pond, Subcritical, Wet FGD 17.927 0.804 Freshwater, Cooling Pond , Subcritical, Dry FGD 17.902 0.779 Freshwater, Cooling Pond , Subcritical, No FGD 17.859 0.737 Freshwater, Cooling Pond, Supercritical, Wet FGD 15.057 0.064 Freshwater, Cooling Pond , Supercritical, Dry FGD 15.035 0.042 Freshwater, Cooling Pond , Supercritical, No FGD 14.996 0.004

Table D-2 – National Average Withdrawal and Consumption Factors for Model Nuclear Plants

Model Plant Withdrawal Factor (gal/kWh) Consumption Factor (gal/kWh) Freshwater, Once-Through 31.497 0.137 Freshwater, Recirculating 1.101 0.624

Table D-3 – National Average Withdrawal and Consumption Factors for Model Fossil Non-Coal Plants

Model Plant Withdrawal Factor (gal/kWh) Consumption Factor (gal/kWh) Freshwater, Once-Through 22.74 0.09 Freshwater, Recirculating 0.25 0.16 Freshwater, Cooling Pond 7.89 0.11

Table D-4 – National Average Withdrawal and Consumption Factors for Model IGCC/NGCC Plants

Model Plant Withdrawal Factor (gal/kWh) Consumption Factor (gal/kWh)
NGCC, Freshwater, Once-Through 9.01 0.02 NGCC, Freshwater, Recirculating 0.15 0.13 NGCC, Freshwater, Cooling Pond 5.95 0.24 NGCC Air Cooled 0.004 0.004 IGCC, Freshwater, Recirculating 0.226 0.173Freshwater Needs for Thermoel ectric Generation, September 2008

E-1 

### Appendix E Combined-Cycle Power Plants: Relative Contributions fr om Gas and Steam Turbines

Combined-cycle power plants integrate the pow er generating capabilities of gas turbines and steam turbines in a highly efficient ma nner. The waste heat generated by fuel combustion in the gas turbine is recovered in a heat recovery steam generator, producing steam that is then used to generate additiona l power in the steam turbine. A common rule of thumb for combined-cycle design is that the gas turbine capacity is about twice that of the steam turbine (i.e., steam turbine output represents about one-t hird of total plant output).

The water needs analysis incorporates th is rule of thumb by applying the water withdrawal and consumption factors to only one-third of the combined-cycle capacity. To justify this assumption, the Platts World Electric Powe r Plants Database was analyzed. For those plants reporting gas turbine and steam turbine capacity in a combined-cycle configuration, the database produced the numbers shown in the table below.

Table E-1 - Gas and Stea m Turbine Contribution Capacity (MW) Percentage Number of units Percentage Gas turbines in combined-cycle configuration 93,526 62.1% 846 63.2%

Steam turbines in combined-cycle configuration 57,068 37.9% 493 36.8%

Total 150,594 100.0% 1339 100.0%

Steam turbine capacity represents about 38% of total combined-cycle capacity. While the data do not precisely equal the 2:1 ratio pos ited by the rule of thumb, the agreement is fairly close. Industry product evolution and individual plant design data also support the 2:1 ratio. Siemens Power Generation recen tly expanded its product portfolio with the SGT5-8000H gas turbine, featurin g advanced H-class efficiency. 27 This turbine will be capable of producing about 340 MW in simp le-cycle configuration, and about 530 MW in combined-cycle configuration, resulting in a steam turbine percentage of 35.8%. In the forthcoming NETL report, “2006 Cost and Performance Comparison of Fossil Energy Power Plants,” the steam turbine in the natural gas-fired combined-cycle design represents 29.2% of total plant output. 28

Based on this information, assuming that the water scaling factors should only be applied to one-third of the generating capacity fo r combined-cycle plants appears quite reasonable.Freshwater Needs for Thermoel ectric Generation, September 2008

F-1 

### Appendix F Results from Statistical Analysis of Water Usage Factor Data

Figure F-1 – Boxplot for All Water Usage Factor Data for Coal Recirculating Subcritical Category

Recirculating Subcritical 120000.00

100000.00

80000.00

60000.00

40000.00

20000.00

0.00gal/MWh

Figure F-2 - Boxplot for Water Usage Fa ctor Data for Coal Recirculating Subcritical Category with Outliers Eliminated

Recirculating Subcritical 800.00

600.00

400.00

200.00

0.00gal/MWhFreshwater Needs for Thermoel ectric Generation, September 2008

F-2 Figure F-3 – Boxplot for All Water Usage Factor Data for Coal Recirculating Supercritical Category

Recirculating Supercritical 100000.00

80000.00

60000.00

40000.00

20000.00

0.00gal/MWh

Figure F-4 - Boxplot for Water Usage Fa ctor Data for Coal Recirculating Supercritical Category with Outliers Eliminated

Recirculating Supercritical 1200.00

1000.00

800.00

600.00

400.00

200.00gal/MWhFreshwater Needs for Thermoel ectric Generation, September 2008

F-3 Figure F-5 – Boxplot for All Water Usage Factor Data for Coal Once-Through Sub critical Category

Once-Through Subcritical 10000000.00

8000000.00

6000000.00

4000000.00

2000000.00

0.00gal/MWh x Design Temperature Rise

Figure F-6 - Boxplot for Water Usage Fa ctor Data for Coal Once-Through Subcritical Category with Outliers Eliminated

Once-Through Subcritical 1000000.00

800000.00

600000.00

400000.00

200000.00gal/MWh x Design Temperature RiseFreshwater Needs for Thermoel ectric Generation, September 2008

F-4 Figure F-7 – Boxplot for All Water Usage Factor Data for Coal Once-Through Supercritical Category

Once-Through Supercritical 1000000.00

800000.00

600000.00

400000.00

200000.00gal/MWh x Design Temperature Rise

Figure F-8 - Boxplot for Water Usage Fa ctor Data for Coal Once-Through Supercritical Category with Outliers Eliminated

Once-Through Supercritical 600000.00

550000.00

500000.00

450000.00

400000.00

350000.00

300000.00

250000.00gal/MWh x Design Temperature RiseFreshwater Needs for Thermoel ectric Generation, September 2008

F-5 Figure F-9 – Boxplot for All Water Usage Factor Data for Coal Cooling Pond Subcritical Category

Cooling Pond Subcritical 800000.00

600000.00

400000.00

200000.00

0.00gal/MWh x Design Temperature Rise

Figure F-10 – Boxplot for All Water Usage Factor Data for Coal Cooling Pond Supercritical Category

Cooling Pond Supercritical 1750000.00

1500000.00

1250000.00

1000000.00

750000.00

500000.00gal/MWh x Design Temperature RiseFreshwater Needs for Thermoel ectric Generation, September 2008

F-6 Figure F-11 - Boxplot for Water Usage Factor Data for Coal Cooling Pond Supercritical Category with Outliers Eliminated

Cooling Pond Supercritical 502000.00

500000.00

498000.00

496000.00

494000.00

492000.00

490000.00gal/MWh x Design Temperature Rise

Figure F-12 – Boxplot for All Water Usage Factor Data for Fossil Non-Coal Recirculating Category

Fossil Non-Coal Recirculating 400000.00

200000.00

0.00gal/MWhFreshwater Needs for Thermoel ectric Generation, September 2008

F-7 Figure F-13 - Boxplot for Water Usage Factor Data for Fossil Non-Coal Recirculating Category with Outliers Eliminated

Fossil Non-Coal Recirculating 1200.00

1000.00

800.00

600.00

400.00

200.00

0.00gal/MWh

Figure F-14 – Boxplot for All Water Usage Factor Data for Fossil Non-Coal Once-Through Category

Fossil Non-Coal Once-Through 10000000.00

8000000.00

6000000.00

4000000.00

2000000.00

0.00gal/MWh x Design Temperature RiseFreshwater Needs for Thermoel ectric Generation, September 2008

F-8 Figure F-15 - Boxplot for Water Usage Factor Data for Fossil Non-Coal Once-Through Category with Outliers Eliminated

Fossil Non-Coal Once-Through 1200000.00

1000000.00

800000.00

600000.00

400000.00

200000.00

0.00gal/MWh x Design Temperature Rise

Figure F-16 – Boxplot for All Water Usage Factor Data for Fossil Non-Coal Cooling Pond Category

Fossil Non-Coal Cooling Pond 400000.00

200000.00

0.00gal/MWh x Design Temperature RiseFreshwater Needs for Thermoel ectric Generation, September 2008

F-9 Figure F-17 – Boxplot for All Water Usage Factor Data for Nuclear Recirculating Category

Nuclear Recirculating 125000.00

100000.00

75000.00

50000.00

25000.00

0.00gal/MWh

Figure F-18 - Boxplot for Water Usage Factor Data for Nuclear Recirculating Category with Outliers Eliminated

Nuclear Recirculating 3000.00

2500.00

2000.00

1500.00

1000.00

500.00

0.00gal/MWhFreshwater Needs for Thermoel ectric Generation, September 2008

F-10 Figure F-19 – Boxplot for All Water Usage Factor Data for Nuclear Once-Through Category

Nuclear Once-Through 2500000.00

2000000.00

1500000.00

1000000.00

500000.00

0.00gal/MWh x Design Temperature Rise

Figure F-20 - Boxplot for Water Usage Factor Data for Nuclear Once-Through Category with Outliers Eliminated

Nuclear Once-Through 1000000.00

800000.00

600000.00

400000.00

200000.00gal/MWh x Design Temperature RiseFreshwater Needs for Thermoel ectric Generation, September 2008

G-1 

### Appendix G Carbon Capture Technologies

This appendix briefly describes the carbon captu re technologies used for this analysis. Though other pre- and post-combustion carbon capt ure systems could be applied, such as other solvent based systems, sorbents, and me mbranes, the systems described below were selected because of the available data and th at they are further developed compared to some of the emerging technologies. For a ll retrofit, new PC and new IGCC plants, a nominal 90% CO 2 capture rate is used. The captured CO 2 is dried and compressed to 2,200 psig.

PC Retrofits and New Builds with Carbon Capture All retrofitted and new PC plants are assu med to use monoethanolamine (MEA) solvent based absorption systems to remove the CO 2 from the flue gas. This solvent based process is designed to recover high-purity CO 2 from low-pressure streams that contain oxygen. The process uses a stri pping tower to recover the CO 2 from the solvent.

The additional water required for both PC retrofits and new PC plant with the solvent based carbon capture technologies is larg ely due to the additional cooling water requirements used for these systems. Cooling water is indirectly used to lower the temperature of the flue gas down to approxima tely 100°F. The water in the flue gas is condensed out and internally used within th e plant. The compression and dehydration of the CO 2 is the other process that increas es cooling water use. As the CO 2 is compressed, heat is generated. Interc oolers are used between compre ssion stages to cool the CO 2 fluid. Additional cooling water within the CO 2 capture system is also used for water wash cooling, absorber intercooling, reflux condens er, reclaimer cooling, and lean solvent cooler. 16

For the PC retrofits, it is assumed that the sulfur levels in the flue gas are acceptable for the carbon capture system. All additional co oling systems required for the retrofits will be recirculating. Makeup water for the amin e system is drawn from the recycled water that is condensed from the flue gas.

New IGCC Plants with Carbon Capture For this analysis, all IGCC plants with car bon capture technologies utilize a two-staged Selexol process. Untreated syngas ente rs the first of two absorbers where H 2 S is preferentially removed using loaded solvent form the CO 2 absorber. The gas exiting the first absorber passes through th e second absorber where the CO 2 is removed. Additional water used for the capture technologies is due to the increased cooling load required to further cool the syngas before entering the Selexol process and steam for the water gas shift (WGS) reactor. The WGS reactors are lo cated before the Selexol unit and convert the carbon monoxide (CO) to CO 2 . Water is required for this reaction:Freshwater Needs for Thermoel ectric Generation, September 2008

F-2 CO + H 2 O ↔ CO 2 + H 2

Products from the gasifier are humidified with steam or water and contain a portion of the water vapor necessary to meet the wate r-to-gas criteria at the reactor inlet.Freshwater Needs for Thermoel ectric Generation, September 2008

R-1 

### References

1 Energy Information Administration, Annual Energy Outlook 2008 with Projections to 2030
, http://www.eia.doe.gov/oiaf/aeo/index.html , June 2008.
2 DOE/NETL. Estimating Freshwater Needs to Meet 2025 Electricity Generating Capacity Forecasts

. http://www.netl.doe.gov/technologies /coalpower/ewr/pubs/Estimating% 20Freshwater%20Needs%20to%20 2025.pdf , June 2004.
3 Power Plant Water Consumption Study , Michael G. Klett, Norma J. Kuehn, Ronald L. Schoff, Vladimir Vaysman, Jay S. White, U.S. Department of Energy, National Energy Technology Laboratory, August 2005. http://www.netl.doe.gov/technologies/c oalpower/gasification/pubs/pdf/WaterReport_IGCC_Final_August2 005.pdf
4 United States Geological Survey (USGS). Estimated Use of Water in the United States in 2000 ; USGS Circular 1268; March 2004.
5 USGS. Estimated Use of Water in the United States in 1995 ; USGS Circular 1200; 1998. http://water.usgs.gov/watuse/pdf1995/pdf/circular1200.pdf
6 Energy Information Administration. Annual Energy Outlook 2008 , EIA Report No. DOE/EIA0383(2008); June 2008.
7 GAO, Freshwater Supply: States’ View of How Federa l Agencies Could Help Them Meet the Challenges of Expected Shortages , July 2003.
8 U.S. Census Bureau, http://www.census.gov/population/cen2000/map01.gif
9 National Oceanic and Atmospheric Administration, National Climatic Data Center
10 USGS and USDOI, Water Availability for the Western United States – Key Scientific Challenges , USGS Circular 1261, 2005
11 Platts, The McGraw-Hill Companies, Inc., North American Energy Business Directory, World Electric Power Plants Database . December 2005.
12 EIA Form 767 data, years 2000 and 2005
13 EPRI, Water & Sustainability (Volume 3): U.S. Water Consumption for Power Production – The Next Half Century , Topical Report No. 1006786, March 2002.
14 Integrated Environmental Control Model , Carnegie Mellon University, 2004. http://www.iecmonline.com/
15 U.S. Department of Energy, National Energy Technology Laboratory, Carbon Dioxide Capture from Existing Coal-Fired Power Plants , December 2006.
16 U.S. Department of Energy, National Energy Technology Laboratory, Cost and Performance Comparison Baseline for Fossil Energy Power Plants , May 2007.
17 Energy Information Administration, Annual Energy Outlook 2007 with Projections to 2030 , EIA Report No. DOE/EIA-0383(2007), February 2007.
18 National Energy Technology Laboratory, Power Plant Water Usage and Loss Study , August 2005.
19 GAO, Freshwater Supply: States’ View of How Federa l Agencies Could Help Them Meet the Challenges of Expected Shortages , July 2003
20 DOI, Federal Drought Action Team will Coordinate Drought Relief Assistance to Western States , July 2005
21 Shea Anderson, Reuters, Idaho Committee Adopts Moratorium on Coal Power , March 14, 2006.
22 Land Letter. Western Power Plants Come Under Scrutiny as Demand and Drought Besiege Supplies; March 4, 2004; http://www.e enews.net/Landletter.htm
23 Billingsgazette.com. South Dakota Governor Seeks Summit on Missouri River , February 2005.
24 Milwaukee Journal Sentinel. Wisconsin Energy Just Can’t Stay Out of the News with Their Intake Structures , February 18, 2005.
25 Erny Zah, The Daily Times, Desert Rock Water Agreement Passes Navajo National Committee , February 2, 2006
26 The Associated Press, Sempra Energy Halts Gerlach Project Study , March 8, 2006
27 http://www.powergeneration.siemens.com/en /gasturbinesitem/ls/sgt5_8000h/index.cfm
28 U.S. Department of Energy, National Energy Technology Laboratory, 2006 Cost and Performance Comparison of Fossil Energy Power Plants , June 2006Freshwater Needs for Thermoel ectric Generation, September 2008

R-2