At the urging of the California Public Utility Commission (CPUC) and the California Energy Commission (CEC), on July 1, the California Independent System Operator (CAISO) announced its intent to procure additional capacity to meet this summer’s electricity demand. California is one of several power regions in the U.S. that are at risk of grid emergencies this summer.


Already in 2021, record-setting heatwaves across the Pacific Northwest have resulted in power outages for thousands of electricity customers. Utilities across the West have implemented rolling blackouts, disconnecting different load centers for short periods of time to reduce total system electricity demand and maintain the electric grid’s stability when not enough resources were available to meet the total electric demand.

A Lack of Dispatchable Power

In August 2020, when a major heatwave extended across much of the West, and wildfires raged in California and neighboring states, as many as two million California customers were left without electricity, the first rolling blackouts in the state since the California Energy Crisis of 2001. Notably, however, the August 2020 peak demand of 47,121 MW was far below the state’s record—50,270 MW on July 24, 2006—or the 50,116 MW tallied in 2017, when CAISO avoided cutting electric service to its customers.

Michelle Bloodworth

The biggest difference between the events of August 2020 and the record peak demand days of 2006 and 2017 is California’s massive shift away from dispatchable fossil fuel power plants and toward intermittent renewables in the pursuit of meeting its ambitious decarbonization goals. According to U.S. Energy Information Administration (EIA) data, solar and wind capacity accounted for about 5% of CAISO’s generating fleet in 2010, with fossil fuel-fired dispatchable power plants accounting for roughly 70% of capacity. A decade later, wind and solar account for almost 30% of total capacity, while the capacity share of coal and natural gas has fallen to less than 50%.

Solar, in particular, saw tremendous growth over the last decade, growing from about 1% of CAISO’s capacity in 2010 to nearly 20% only 10 years later. Currently, solar generating resources provide most of the electricity needed in California during the midday hours, but solar output falls dramatically in the evening hours when the sun sets but electricity demand remains high. Without enough dispatchable resources available to fill the gap left by these solar resources, demand is liable to exceed available supply.

Power Imports in Tight Supply

Besides relying on dwindling in-state dispatchable fossil generation to fill the gap left by waning solar output, the California grid operator has grown more reliant on power imports from its neighboring states. Most of these power imports have come from hydropower and fossil fuel-fired power plants, both of which are growing increasingly limited in supply.

Arizona, New Mexico, Nevada, Washington, and Oregon—which all export power to California—have been setting their own clean energy goals, and closing fossil plants in the process. Since 2013, these six states have retired more than 10 GW of fossil fuel generating capacity, with much more to come. States that were once able to export their excess dispatchable power generation will soon find themselves in the same situation as California—desperate for imports.

Exacerbating California’s supply woes is the lack of available electricity from hydropower facilities. The Western U.S. experienced one of the worst droughts in its history during the first four months of 2021. In fact, the 2021 water year so far is the third-driest in 100 years and the driest since 1977. The nation’s largest reservoir, Lake Mead, is headed for its lowest level since it was first filled in the 1930s.

The CPUC and CEC, in a joint letter to CAISO, estimated that drought conditions have already reduced California’s hydro capacity by 1,000 MW. Nearby states, including Oregon and Washington, are also experiencing much-lower-than-average water levels in their reservoirs, reducing available hydropower generation that California has often relied on in the past to meet its electricity demand during summer heatwaves.

None of the issues that have California scrambling for additional generating resources to meet electricity demand this summer were completely unexpected. While recent heatwaves in 2020 and 2021 set temperature records across certain areas, electricity demand remained below previous record levels. Fossil fuel retirements across the region were announced years in advance, driven by regulatory pressure from state agencies on utilities to decrease their reliance on fossil fuels to achieve politically driven ambitious decarbonization goals.

However, California regulators have failed to consider all of the factors that affect resource adequacy, or underestimated their true impact. To make matters worse, California’s only remaining nuclear plant—the 2,200-MW Diablo Canyon facility—is slated to be fully retired by 2025, without clear plans on how to reliably replace this massive amount of capacity.

Poor resource planning in California and much of the West means that rolling blackouts like the ones Californians experienced last summer will be a looming risk in the region for the foreseeable future. Let’s make sure that the rest of the country learns from California’s mistakes.

Michelle Bloodworth is president and CEO of America’s Power, the only national trade organization whose sole mission is to advocate at the federal and state levels on behalf of coal-fueled electricity and the coal fleet.