Potential Benefits and Opportunities for Load Following Geothermal Power Plants in California

摘要

California's current Renewable Portfolio Standard (RPS) requires 50% of the state's electricity come from renewable resources by 2030. These requirements for renewable energy usage have facilitated the deployment of intermittent resources such as wind and solar. Oversaturation of intermittent energy resources creates challenges in meeting real-time electricity demands and maintaining grid reliability. Forecasts from the California Independent System Operator predict that by 2020, the decrease in solar photovoltaic electricity generation at the end of a typical spring day will routinely require other energy sources to increase electrical power generation by 13,000 MWe over a timeframe of three hours. Although fossil energy technologies are currently used to provide ramping capabilities, these technologies do not help meet California's RPS requirements. As a dispatchable resource, geothermal power plants can provide electric power ramping capabilities while fulfilling the RPS requirements. Previous geologic studies estimate that undeveloped geothermal resources in California can contribute more than 10,000 MWe of generation capacity using conventional hydrothermal technology and 48,100 MWe of additional capacity if future Enhanced Geothermal Systems technologies are used. Using the undeveloped geothermal resources for load following power plants could meet significant amounts of California's future electrical power ramping needs. Industry consensus is that the flexible operation of geothermal power plants is an established technology and that the primary barriers to load following geothermal are economic, not technical. The deployment of flexible geothermal power depends on the financial opportunities for these plants in their regional energy markets. The objective of this paper is to examine the potential benefits and opportunities of operating geothermal power plants as load following resources to address the future electricity ramping demands in California.