State of California AIR RESOURCES BOARD Biltmore Hotel Galeria Room 515 South Olive Los Angeles, CA September 30, 1977 10:00 a.m. AGENDA Page 77-21-1 Continuation of Public Hearing to Consider Amendment of South Coast Air Quality Management District Rules and Regulations re Use of Natural Gas During Air Pollution Emergency Episodes and Status Report on Compliance with Rule 715.1. 77-21-2 Status Report on Chevron LSFO Investigation. 77-21-3 Report on Air Pollution Control Problems at Geothermal 1 Power Plants. 77-21-4 Other Business - a. Research Proposals b. Executive Session - Personnel & Litigation ITEM NO.: 77-21-3 Report on Air Pollution Control Problems at Geothermal Power Plants. RECOMMENDATION 1. The Air Resources Board should consider becoming more involved in geothermal energy issues. 2. If the Board wishes to become more involved the ARB staff should study further the adequacy of the local APCD programs and the coordination between counties to determine how an improved and unified approach can best be achieved. 3. The Board should consider directing the staff to develop model air pollution regulations for geothermal developments for proposal to the districts or adoption by the Board. SUMMARY Geothermal steam and hot water could potentially satisfy a substantial amount of California's electrical power requirements without the adverse environmental impacts associated with the combustion of fossil fuels or the risks associated with the storage of radioactive wastes. The geothermal powerplants at The Geysers in Northern California are presently generating about 500 Megawatts (MW) of electric power which is approximately four percent of California's current electric power demand. With the exception of hydro-power, the electricity produced at The Geysers is less expensive than electricity from all other sources. Power production at The Geysers can potentially be expanded to between 1,750 and 5,000 MW, however, the current level of power production in Sonoma County has already generated complaints from residents of Lake County located several miles downwind of the rugged and unpopulated area where the power production activity is now concentrated. Odor from hydrogen sulfide gas which is contained in the steam must be more stringently controlled if the power production is to continue or expand. Although the present control program of the Northern Sonoma County APCD has reduced somewhat the H2S emissions, and will reduce them further, full development of the resource requires more stringent controls than are necessary to meet the District's regulations. A new approach to H2S abatement, different from the approaches encouraged by the regulations of the local APCD's, appears preferable. Current regulations treat the steam producer and the power plant operator (PG&E). However, pre-cleaning of the steam before it is delivered to the power plant appears to be a superior approach. At present, four new powerplants totaling about 400 MW are under construction and application has been made to the PUC for approval of two more with a combined capacity of 200 MW, one in Sonoma and one in Lake County. The violation of the air quality standard in one county as a result of sources in the other raises complex questions as to how the geothermal resources in both counties can be developed without causing continued air quality problems. The Board may need to play a more active role in the regulation of electricity generation from geothermal energy if the full potential of the state's geothermal resources are to ever be used to reduce dependence on sources of electric power which are more damaging to the environment.