September Is Here. That Means Another Nail-Biter for California’s Grid.

August 31, 2022 | 11:38 am
Western Area Power/Flickr
Mark Specht
Western States Energy Manager/Senior Analyst

For a lot of folks, September brings to mind the end of summer, the time to go back to school and get back into the swing of work and home routines, and of course the classic Earth, Wind & Fire song.

But not for me.

For California power grid experts, September is a nerve-wracking month, still very much part of danger season on the West Coast. At any point in the summer, extreme heat could trigger electricity supply shortages and rotating power outages. But September is the month when this type of power outage is most likely in California.

How well has California’s grid been performing this summer?

Compared to the past couple of years, California’s grid has actually been doing pretty well this summer. When grid conditions are tight, California’s grid operator issues Flex Alerts. It issued five Flex Alerts in 2020, eight in 2021, but there’s only been one so far this year. There also haven’t been any grid emergencies yet this summer, which is quite encouraging compared to the two rotating outages that happened during the extreme heat wave in 2020 (Stage 3 emergency) and the close call when wildfire smoke took out transmission lines in 2021 (Stage 2 emergency).

The relative lack of power grid issues is due at least in part to the fact that, this week aside, California has experienced somewhat less extreme heat this summer and the state’s wildfire season has so far been less destructive than during the past two years.

But this shouldn’t be a cause for complacency. September is here, and all it takes is one big heat wave to throw the grid into turmoil.

Why is September the toughest month for California’s grid?

In reality, a big heat wave could lead to electricity supply shortages and rotating power outages during any summer month, but September is when it’s most likely. There are two main reasons for this:

  • Extreme heat waves can occur well into September. Unlike many other parts of the country, California experiences some of its hottest weather in the late summer, with some coastal areas experiencing their highest temperatures in September, or even October.
  • Solar energy production starts to dwindle by September. Solar power peaks earlier in the summer when the days are longer. By September, the sun sets earlier in the evening, and solar power production tapers off when people are still using substantial amounts of electricity in the evening.

The concern is that, if an extreme heat wave were to strike the state in September, Californians would continue to crank their air conditioning well into the evening after solar power production has dropped off. It’s during the evening hours, around 6 to 8 p.m., when power outages are most likely. For example, the two rotating blackouts in August 2020 occurred during energy supply shortages that happened at 6:38 to 7:40 p.m. and 6:28 to 6:48 p.m. In addition, analysis after analysis after analysis shows that September evenings are the toughest time for California’s grid.

September is the toughest month for California’s power grid because an extreme heat wave could lead to very high electricity demand after the sun sets and solar power production tapers off. (Photo: Tom Brewster Photography/Flickr)

Will September always be the toughest month?

A couple years ago, it blew my energy-nerd mind to learn that California’s grid will eventually face its biggest reliability challenges not in September, but during cold winter mornings, especially in December.

December??? I know! Let me explain.

Right now, California’s grid reliability problems happen during summer heat waves when electricity demand is at its highest, but over the next couple decades, the grid will change dramatically.

As California decarbonizes its economy, the state will build enormous amounts of renewable energy and energy storage to clean up the electricity sector. And to clean up buildings and industry, many residences and businesses will switch to electricity-powered heating systems (e.g., heat pumps!).

Putting those two things together, we’ll have so much renewable power and so much energy storage that grid reliability in the summer just won’t be much of an issue. Instead, reliability concerns will be concentrated in overnight hours on cold winter days when the sun isn’t shining, the wind isn’t blowing, storage batteries have been drained, and people turn on their electric heat when they wake up in the morning in a chilly home.

Grid modeling studies indicate that it’s going to be a couple of decades before California grid reliability problems shift from summer to winter (e.g., check out this study on page 32), so there’s no need to worry about this transition quite yet. But this shift is an eventual reality that California policymakers need to keep in mind as they design long-term programs to ensure grid reliability.

What can Californians do to help the grid today?

I’d be remiss not to mention that, ever since the August 2020 power outages, California policymakers and regulators have been pulling out all the stops to maintain grid reliability. During the last couple of summers, California Gov. Gavin Newsom made a habit of waiving all state environmental rules to allow fossil fuel power plants and backup generators to run without restrictions when the grid was under stress. This summer, Newsom managed to get a sweeping energy budget bill passed that gives a state agency the authority to buy electricity from existing fossil fuel power plants and build new emergency or temporary power plants as well. And in late-breaking news, the California Legislature will vote tonight on a bill that would extend the life of the state’s last nuclear power plant, Diablo Canyon, to help alleviate anticipated grid reliability shortfalls in 2025. I’m not going into the pros and cons of these various measures, but suffice it to say that each one is problematic in its own way, and decisionmakers clearly need more options as the grid transitions from fossil fuels to renewable and clean energy sources.

All that being said, it’s still 2022 and September is upon us. The solar, wind, nuclear, hydropower, geothermal, energy storage and natural gas on the grid right now are the resources the state has this month. If California faces electricity supply shortages this September, the state won’t be able to increase the supply very much, but reducing or shifting demand is still an option! Every Californian can help ease the strain on the grid because, when the grid is under stress, people’s energy saving actions can make a big difference. For example, residents can easily cool down their homes early in the day, turn off major appliances in the afternoon and evening hours, and charge their cars overnight. Businesses, too, can play their part by shifting power use to earlier in the day when supplies are more available.

California regulators recently created a slew of new programs to reduce demand on the hottest summer days. For instance, there’s a new Power Saver Rewards program that pays residential customers for reducing their electricity consumption when California’s grid operator calls a Flex Alert. (You can sign up to receive Flex Alerts, or you can enroll in the Power Saver Rewards programs run by Pacific Gas & Electric, Southern California Edison, or San Diego Gas & Electric depending on which utility territory you live in.)

With a little luck, California’s grid will make it through this September unscathed. Then the state will have a brief reprieve to continue the most important task at hand: building much more solar, wind and energy storage to make the grid cleaner and even more reliable before next summer rolls around.