Solar supply and residents’ demand
California already has a great deal of solar electricity being generated, both on buildings and in large-scale solar farms. For example, years of Prop 39 projects for school districts around California have been completed, installing megawatts of solar farms on campuses. These sites were targeted, in part, due to lower summer occupancies, and net metering rules allowed them to reap large financial benefits. Most of these campuses are net exporters of clean renewable energy all summer long. Every day, the managers of the electrical grid must stabilize local electric networks to share this abundant load throughout the day, and quickly ramp up centralized power once the sun goes down and folks head home.
As more all-electric buildings and homes come online, it is important to look at the impacts of these buildings on grid health. The grid must continue to be updated to guard against solar saturation: where solar generation exceeds the total usage in a given area. The grid is managed by local utilities and state agencies, and this balance of supply and demand drives time-of-day pricing that encourages responsible usage.
Energy industry experts point to what is known as the “duck curve,” the risk of over-generation of renewable energy (especially solar) and the impact of having to ramp up energy production (most often these are natural gas plants) to respond to rising demand when the sun goes down. In the belly of the duck (the middle of the day), solar production is peaking and electricity sells at a loss. Yes, California is paying other Western states to take solar energy off their grid. This lets baseload generation systems like nuclear, hydroelectric, and some natural gas plants run constantly, as they cannot easily, or cost-effectively, shut down and then come back on daily.