Tetra Tech, Inc.

10306 Eaton Place, Suite 340 Fairfax, VA 22030 phone 703

- 385

- 6000
TO : Paul Shriner , USEPA FROM : Kelly

Meadows DATE: March 11, 2011
SUBJECT: Power Plants L ocated in
Water

- limited environments like the desert areas outside of Las Vegas can be challenging locations for construction of industrial facilities such as power plants, as these sites often require significant water resources. However, given the increasing demand for electricity in L as Vegas, power producers have recently constructed a number of new generating facilities in the vicinity . This memo documents the research into the construction of these facilitie s and the decision criteria used in selecting the facility’s design, particularl y with respect to the cooling s ys tem. Cooling Water Sy stem Design Power plants generate a significant amount of waste heat that must be rejected cooling s ys tems often us e once limited areas are challenging locations to construct new power plants; surface water is usually not available (particularly in large enough quantities for a once and competition fo r groundwater resources may be high (e.g., demand for drinking water supplies). As a result, utility

companies may

opt to construct new facilities with dry cooling, a form of closed

- cycle cooling that consumes very little water and rejects heat to the atm through radiative cooling (instead of evaporative cooling, as in a wet cooling tower). Dry cooling does have drawbacks, including an energy penalt y to operate the fans and radiators. 2 However, these drawbacks are greatl y reduced when dry cooling is incorporated into the design of the power plant (as opposed to a retrofit application); for example, turbine sy stems can be designed to optimize the increased backpressure,

1 Depending on the generating efficiency, as much as 50 generating power and must be rejected. 2 See the Technical Development Document for more information on dry cooling. 

### MEMORANDUM

10306 Eaton Place, Suite 340

, USEPA Kelly Meadows March 11, 2011
Power Plants L ocated in Water

- Li mited Environments limited environments like the desert areas outside of Las Vegas can be challenging locations for construction of industrial facilities such as power plants, as these sites often

water resources. However, given the increasing demand for electricity in L as Vegas, power producers have recently constructed a number of new generating facilities in the vicinity . This memo documents the research into the construction of

s and the decision criteria used in selecting the facility’s design, particularl y with respect to the cooling s ys tem. Cooling Water Sy stem Design Power plants generate a significant amount of waste heat that must be rejected

e once - through cooling. However, as discussed above, water limited areas are challenging locations to construct new power plants; surface water is usually not available (particularly in large enough quantities for a once

- through s ys tem) r groundwater resources may be high (e.g., demand for drinking water
As a result, utility

companies may

opt to construct new facilities with dry cooling, a form cycle cooling that consumes very little water and rejects heat to the atm through radiative cooling (instead of evaporative cooling, as in a wet cooling tower). Dry cooling does have drawbacks, including an energy penalt y to operate the fans and However, these drawbacks are greatl y reduced when dry cooling is incorporated into the design of the power plant (as opposed to a retrofit application); for example, turbine sy stems can be designed to optimize the increased backpressure,
Depending on the generating efficiency, as much as 50

- 70 percent of the heat generated is not used in generating power and must be rejected. See the Technical Development Document for more information on dry cooling. 1 limited environments like the desert areas outside of Las Vegas can be challenging locations for construction of industrial facilities such as power plants, as these sites often

water resources. However, given the increasing demand for electricity in L as Vegas, power producers have recently constructed a number of new generating facilities in the vicinity . This memo documents the research into the construction of

s and the decision criteria used in selecting the facility’s design, particularl y

Power plants generate a significant amount of waste heat that must be rejected 1 and through cooling. However, as discussed above, water

limited areas are challenging locations to construct new power plants; surface water is through s ys tem) r groundwater resources may be high (e.g., demand for drinking water
As a result, utility

companies may

opt to construct new facilities with dry cooling, a form cycle cooling that consumes very little water and rejects heat to the atm osphere through radiative cooling (instead of evaporative cooling, as in a wet cooling tower). Dry cooling does have drawbacks, including an energy penalt y to operate the fans and However, these drawbacks are greatl y reduced when dry cooling is incorporated into the design of the power plant (as opposed to a retrofit application); for example, turbine sy stems can be designed to optimize the increased backpressure,
70 percent of the heat generated is not used in2

therefore reduci ng the loss of generating efficiency ty picall y seen in closed

- cy cle sy stems. New Power Plants According to some estimates, Las Vegas has a power demand of approximately 4.8 gi gawatts. 3 Given the growth in the area, generating capacity has been added to meet the demand. Some alternative energy (primaril y solar and wind) capacit y has been added but new power plants were still necessary

. Through internet research and information from the Department of Energy’s Energy Information Administration (EIA) ] , Tetra Tech was able to identify several power plants that are located in the Las Vegas area , with many being constructed in recent y ears . Table 1 below lists these facilities. 4 Table 1. New Power Plants in the Las Vegas Vicinity Facility Name Owner Gen erating Capacity (MW) Fuel Type Operational Year Cooling

System Type 1 Water

Source
Chuck Lenzie Nevada

Power 1465 Natural gas combined cycle 2006 Dry cooling Well

Clark Nevada

Power 1377 Natural gas combined cycle and combustion turbines 1955 Mechanic al draft Munici

pal

Walter Higgins Nevada

Power 688 Natural gas combined cycle 2004 Dry cooling Grey

water
Silverhaw k Pinnacle

West 664 Natural gas combined cycle 2004 Dry cooling Well

Reid Gardner Nevada

Power 636 Coal 1965 Mechanic al draft Well,

river Apex Las Vegas

Power Company 600 Natural gas combined cycle 2003 Dry cooling Well

Las Vegas Cogenerati on SWG Nevada 297 Natural gas combined cycle 2003 Mechanic al draft Munici

pal Harry Allen Nevada

Power 186 Natural gas combined cycle and combustion turbines 1995 Dry cooling Munici

pal and well

Saguaro NRG Energy 127 Natural gas 1991 Dry Grey

3 http://www.caslon.com.au/economyguide22.htm 4 Note that this is not intended to be an exclusive list. Some are small o r similar to others listed. Others may only have combustion turbines, which typically do not use cooling water.3

Facility Name Owner Gen erating Capacity (MW) Fuel Type Operational Year Cooling

System Type 1 Water

Source and Paragon Assets combined cycle cooling water Source: Energy Justice Network mapping tool. http://www.energyjustice.net/map/ 1 Information confirming the cooling system type was difficult to locate; this assessment is based on aerial photos, available online information, and conversations with Nevada staff. Several facilities also appear to use cooling ponds. Little information on the permitting process was readily available, but all indications are that many of the new plants were constructed in areas with very little water, making dry cooling the onl y av ailable option. Additionally , man y of these facilities would not be subject to national requirements under the proposed rule, as they d o not meet the scoping criteria; withdrawals are not from surface waters and several facilities do not have NPDES permit s.