Thermal Efficiency of Gas-Fired Generation in California: 2018 Update
October 20, 2018
Energy Assessments (200)
Senate Bill 1389 (Bowen and Sher, Chapter 568, Statutes of 2002) directed the California Energy Commission adopt an Integrated Energy Policy Report (IEPR) every two years. This staff paper supports the IEPR technical analyses by describing general trends in the average thermal efficiency of natural gas-fired generation in California from 2001 through 2017. Over this 17-year period, California’s systemwide thermal efficiency improved by 22 percent due to the successful development of new combined-cycle power plants. The leveling off of gains in thermal efficiency in recent years is due to the rapid growth of utility-scale and distributed solar photovoltaic generation reducing the usage of gas-fired generation. Thermal efficiency was also negatively impacted by the return of significant hydroelectric generation after an extended multiyear drought. In 2017, California’s non-greenhouse gas-emitting electric generation accounted for more than 56 percent of total in-state generation, compared to 50 percent in 2016.