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 technical analyses required by the IEPR by describing general trends in the thermal efficiency of natural gas-fired generation in California from 2001 through 2014. Over this 14-year period, California’s gas-fired generation has seen thermal efficiency improvements of 23 percent. The successful development of new combined-cycle plants continues to be the primary reason for the improvement in California’s systemwide heat rate. The thermal efficiency of the state’s current portfolio of noncogeneration natural gas power plants has resulted in 29 percent more energy being generated while using the same amount of natural gas compared to 14 years ago.
