facilities is hydrogen sulfide, contained in the geothermalfluids ex- the salinity of the Salton Sea resulting from use of agricultural Mesaarea. We used computer models of at- hydrogen sulfide released depends. mospheric transport to simulate air quality changes resulting from 3000 MW of energy-generating capacity. The results of our simulations indicate that if hydrogen on its concentration in the geother- mal fluid and the quantity of fluid processed per MWhofelectricity generated. Without control, power | T Cities re L__-+ Niland (i Calipatria ¢ he Geothermal areas = _ 3680 e Geothermal sites uf a 55 g/MWhforfacilities in the East produce steam used to run a turbine generator. The amountof 43 : ol and 160 g/MWh, compared with a potential emission rate of ter these fluids are “flashed” to _ Air quality The principal gaseous pollutant that could be released to the atmosphere from geothermal! -3 area could emit as much as tracted from subsurface reservoirs. It is released to the atmosphere af- waste waters for power plant cooling, and (c) induced subsidence and seismicity associated with the extraction and injection of geothermal fluids. ct pee ee bol} plants in the Salton Sea resource | — ~ 3660 mA | ht Brawley z & 3 = S 3640 |— a. a . Lo = km IBA Qo iI 3600 600 . —_— ic Q <G) | 620 | 640 | 660 UTM coordinates — km 680 Isopleth plot showing estimates of how PIG. & much of the time the California air-quality standard for hydrogen sulfide (42 .g/m* averaged over medium-growth scenario for geothermal one hour) would be exceeded in the Imperial Valley, assuming a geothermal production capacity of 3000 MW. (Along a 1.0 isopleth, the standard is exceeded all the time, along a 0.25 isopleth the standard is exceeded one-fourth of the time, etc.) To prevent violations of the hydrogen sulfide standard at that level of energy development, facilities in the Salton Sea and Brawley resource areas would have to reduce emissions by approximately 82%. year 2010). This siting pattem was prepared to enable us to carry out an assessment of the environmental impact of geothermal operations in the valley. At 3000 MW, powerplants and related facilities will use, at most, only about 0.2% of the land normally irrigated in the valley. 20 9096 G4 ic pUS. 5+ Calexico : development in the Imperial Valley (to 3000 MW in the a t-2 Heber —— Mexico Powerplant siting pattern postulated for a ald | ElCentro Holtviile’ «.,? cee rg ni eal 8 0 1 5 FT | (mperial ‘Seeley | El Centro s - 3620 roi Imperial 2anpe