This past summer, California suffered its first rolling blackouts in nearly 20 years. While many took the opportunity to lambast the state’s renewable and climate policies as a threat to grid reliability, a preliminary analysis of the blackouts released last week by three of California’s energy agencies paints a more nuanced picture. The analysis found that the blackouts’ root causes were: grid operators neglecting to adequately plan for “climate change-induced extreme heat” waves, failure to buy sufficient power supplies to cover the evening hours when solar panels go offline, and practices in day-ahead energy markets that masked inadequate resources. Essentially, it is not that California incorporated higher levels of variable renewable energy (VRE) in recent years, but the lack of adequately planning and retooling a grid with high levels of VRE, coupled with extreme heat, that were the root causes of the blackouts. 

The immediate cause of the blackouts faced by California this past summer was the heatwave that gripped much of the West. Record high temperatures drove high demand for electricity across many western states. So when all of those states needed electricity, there wasn’t any excess to cover gaps. Leading up to the blackout, California also unexpectedly lost 475 MW of gas-fired generation (reduced wind output, which could be linked to high temperatures, also played a role in the blackouts). As western states continue to grapple with extreme temperatures, and the amount of imports available to California declines, the state must ensure it has adequate reserve capacity to manage these contingencies. But as the preliminary analysis indicates, California is ill-prepared to provide power when solar and wind power go offline. 

This is a problem that grid operators might have seen coming. Last year, California’s independent system operator (CAISO) predicted that capacity shortfall would limit the state’s ability to meet summer evening peak load by as soon as…2020. The warning signs were there. Still, as California worked towards its goal of 60 percent renewable energy by 2030 and zero-carbon electricity by 2045, the state closed fossil power plants without providing sufficient alternatives. Since 2018, California has shut down roughly 5 GW of dispatchable generation, but only added about 2,200 MW in non-intermittent resources since then. As stated in the 2019 CAISO presentation, increasing penetration of VRE must be paired with  investment in short and long-duration battery storage, and grid resilience technologies (such as automated demand response). At the same time, it is critical to strategically maintain a diverse portfolio of flexible resources to meet evening electricity peaks. These blackouts are not evidence of renewables’ technical limitations, but rather demonstrate a failure to plan for predictable risks. 

California’s experience highlights what energy analysts have argued for some time: that VRE must be complemented by a diverse portfolio of electricity generation and grid resiliency technologies, such as natural gas peaker plants equipped with CCS, battery storage technologies, and automated demand response. To be clear, the blackouts experienced in California this summer were not caused by variable renewable energy. Rather, they were the result of both the failure to build the wider grid infrastructure necessary to support a low-carbon electricity system, and of a generally lax attitude towards  climate change’s potential impact on the region’s electricity availability. Retreating from California’s climate goals would not solve the issue of blackouts and would only exacerbate the extreme-weather conditions that caused them in the first place. The preliminary analysis findings underscore why it is  imperative to put steel in the ground and build the low-carbon electricity grid needed to stave off dangerous climate change.