Rolling blackouts returned to California this weekend after a 19-year respite for the state. And while the exact causes of these most recent outages are still under investigation, one possible explanation points to more than just a momentary inconvenience. If, as some observers believe, California’s efforts to toggle between fossil fuels and renewable energy sources played a role in leaving Californians without power, climate advocates need to reassure the public that they can keep the lights on — or risk losing public support for the project.

There are a lot of reasons for California’s electrical grid to be under pressure right now. The Western United States is experiencing record high temperatures, driving up demand for air conditioning. That spike is amplified because so much of California’s population is stuck at home under pandemic-related lockdowns.

The stress is particularly acute for a system that relies on renewable energy because that source cannot be dialed up or down to meet demand. The sun is going to shine and the wind is going to blow for the time and intensity nature allows, regardless of human desire for comfort.

Wind flows are not constant, although planners and utilities try to station wind farms in areas that tend to have high and relatively regular winds. Clouds reduce what solar panels can produce, and shorter days in spring and fall mean fewer hours of solar power generation. While states that don’t rely as much on renewables can sometimes export their electricity to states such as California, they are subject to the same fluctuations in demand that don’t match up neatly to available supply.

Under such circumstances, rolling blackouts, which deprive people of any electricity for a set period of time, are the fairest and most efficient way to address this mismatch between electricity supply and demand. They also risk political disaster for renewables.

Even if reliance on alternate energy sources didn’t contribute to particular blackouts, they may well be to blame in the future. Unless officials can find ways to guarantee non-fossil-fueled backup sources for renewables, the more a state such as California relies on renewable “clean” energy, the higher the risk it will be unable to meet demand during peak periods, such as during a heat wave.

The solution requires investment in decentralized generation and storage capacity. If every house in California had solar panels on its roof, it would meet at least some of its own needs from its own source. This relatively stable source of generation would ensure that a house had at least some electricity available in its battery storage, providing redundancy in case of utility failure. California has passed a law mandating that new homes be built with solar panels, something that will add an estimated $8,400 to the cost of the Golden State’s already high home prices. Even that requirement is being resisted by utilities that seek to allow homes to tap into utility-built solar plants, something that keeps homes tied to grids that may not be able to supply electricity full-time in peak demand periods.

Ultimately, the real solution will have to come from extensive investment in battery storage. If wind and solar power could be stored that way, that stockpile could be tapped when demand surges. This can be done for large-scale utilities to fuel the grid, and by homes or smaller businesses, which can have on-site batteries combined with solar or wind generation. Either way, building this infrastructure will likely require significant government subsidies or mandates to ensure that storage capacity rises as quickly as reliance on wind and solar power does.

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Climate activists may also have to bite the bullet and agree to significant expansion of nuclear power. Nuclear plants operate all the time, and thus provide the constant supply of electricity that wind and solar cannot. They are largely safe: No nuclear power plant operating in the United States has ever emitted enough radiation to significantly harm the population. That’s not to say that there aren’t risks, and the problem of disposing of the highly toxic radioactive waste is very real. But if the planet is really at stake because of global warming, it seems these are risks that are worth taking.

People will not submit to rolling blackouts, or worse, as a cost of transitioning toward a carbon-free future. Climate advocates have to ensure that the future they are crafting is reliable as well as green. If they don’t learn these lessons now, don’t be surprised if the public turns back to fossil fuels for its electricity in the future.

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