Geothermal resources in California: potentials and problems

Abstract

The technology, cost and potential of geothermal resources in California are examined. The production of power from dry stream fields is expanding in Northern California, at The Geysers, at costs that compare favorably with alternate means of generation. The possibility exists that economic production: of power can be started in the Imperial Valley, but numerous issues remain to be resolved; chief among them is the demonstration that commercially valuable aquifers indeed exist. The production of demineralized water from the geothermal fluids of the Imperial Valley depends, among other things, upon the identification of other sources of water for power plant cooling, or for reservoir reinjection, should it be necessary to avoid subsidence. It would appear that water production, without the income-producing capability of associated power generation, is not economically reasonable. The pace of geothermal development at the Geysers could probably be accelerated perhaps offering PG&E the opportunity for maintenance of adequate generating reserves should their nuclear construction program be delayed. The unknown factors and risks involved seem to preclude the Imperial Valley resource from being immediately effective in improving the power generation picture in Southern California. However, in the next decade, geothermal power could provide a useful energy increment, perhaps 10% of peak load. Associated water production could offer relief for the Imperial Valley in its predicted water quality problem. The pace of public and private development in the Imperial Valley seems incommensurately slow in relation to the potential of the resource. Geothermal power and water production is not intrinsically pollution-free, but appropriate environmental protection is possible.