Climate-Induced Changes in Peak Energy Demands in California

Previous California-wide studies have shown cooling trends at coastal low elevation areas open to marine air penetration and warming trends at inland and coastal high elevation areas from 1970 to 2010 (Lebassi et al. 2009, Sequera et al. 2012). These warming and cooling trends were determined through the analysis of summertime mean and maximum surface air temperature and pressure trends. Coastal cooling trends were attributed to a reverse reaction global warming, specifically an inland warming induced sea breeze that penetrated coastal low elevation areas. Additional studies have showed correlations between these axisymmetric temperature trends and peak hourly electricity demand (Lebassi et al. 2010). Such studies determined that cooling coastal low elevation areas have decreasing peak hourly electricity demand from 1993 to 2003 during the summer months of June to August. In contrast, warming inland and warming coastal high elevation areas have increasing peak hourly electricity demand during the same time period.

Given the importance of peak energy in defining regional energy infrastructure, this work extends the previous analysis to include a larger temporal scale and electricity data set from the California Energy Commission (CEC), Energy Information Administration (EIA), Federal Energy Regulatory Commission (FERC), and select utility companies in Los Angeles Air Basin (coastal) and Sacramento Valley (inland) regions. An analysis of 1990 to 2010 electricity demand, consumption and generation data for these select coastal and inland areas is consistent with previous studies, showing coastal low elevation areas have lower electricity consumption levels at the annual, monthly, and peak hourly temporal scales at a per capita basis. Analysis of temperatures and hourly energy demand data show strong correlations between peak energy demand with summer average maximum temperatures and heat index for the entire period for both inland and coastal areas. Correlations for summertime annual maximum temperatures confirm previous findings that coastal low elevation areas have decreasing peak hourly electricity demand from 1993 to 2003. However, extended temporal studies show that coastal low elevation areas are experiencing slight increasing peak hourly electricity demand trends from 1993 to 2010. This was probably due to recent short-term increases in annual maximum daily temperatures. In contrast, inland and coastal high elevation areas have increasing peak hourly electricity demand trends from 1993 to 2010, consistent with summer regional warming. It is also shown that heavily urbanized areas have a consistent time lag in higher peak hourly electricity demands induced by the urban heat island effect, while energy sectorial analysis show that the residential sector is the climate sensitive.