Last year I wrote a blog about the California “duck curve,” our state animal to think or freak out about solar production and curtailment issues. I noted that while hyperventilation is not yet necessary, “as renewables hit higher and higher penetrations of our electricity mix, there are legitimate renewable integration issues for the state to address.”
Updating for 2018 data shows not much has changed.
This time, let’s take a closer look at when too much solar becomes an issue. Curtailment occurs predominately in the Spring and Fall, during low-load, high-solar periods. In fact, in 2018, 70% of solar curtailment occurred in four months — March through May and October.
Thus, solutions to address solar integration issues should primarily focus on the specific months (Spring and to a lesser extent Fall) and hours (mid-day) when curtailment is most acute. Since most solar curtailment is not due to system “oversupply,” as is commonly misunderstood, but is “economic,” e.g. due to very low/negative prices, granular price signals that can be captured by customers with specific technologies (e.g. battery storage) or willingness and ability to shift load (some commercial customers?) will likely be helpful to increase load and avoid curtailment on a granular time-scale.
In the end, I suspect solar developers will increasingly incorporate battery storage directly to shift more production on-peak and capture higher prices. And, who knows, perhaps greater reliance on alternative technologies like off-shore wind will provide a nice complement to the state’s solar production, taking our worries away from the duck and towards sustainable development for the fishes.
