| Title | Water Use in Geothermal Power Plants |
|---|---|
| Authors | Farison, John |
| Year | 2010 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Evaporative cooling; Reclaimed water; Fresh water; Reservoir recharge |
| Abstract | Water usage in geothermal power plants is often misreported. The amounts and types of water used for geothermal power plants varies widely with the type of resource, the power plant technology and the type of waste heat rejection system. Today’s geothermal power plants do not use once-through cooling. Geothermal dry steam and flash plants create their own cooling water from steam condensate and mechanical draft cooling towers are typically used for waste heat rejection. Lower temperature geothermal resources typically use air cooled condensers or hybrid wet/dry cooling. Geothermal typically has minimal impact on fresh water or groundwater sources. Geothermal fluids are distinctly different from fresh water sources and must be kept separate and returned to the reservoir. Geothermal can make use of low quality waters for reservoir recharge. The Geysers use of municipal reclaimed water from Lake County and Santa Rosa for reservoir recharge is a major success story. Reservoir recharge at The Geysers with reclaimed water now averages about 77% mass replacement on an annual average basis and helps to sustain steam production and generation. Strategic water injection across the Geysers field has become another important tool for reducing gas content in steam and helps reduce abatement system operating costs. |