This past weekend, California experienced two consecutive days of power outages, and more are possible in the days to come. Prior to this past week, this type of power outage had not happened in the state since the California Electricity Crisis almost two decades ago.
In the midst of a global pandemic and a west-wide heatwave, rolling blackouts—or rotating outages as the experts call them—are exactly the last thing Californians needed right now. For some, a power outage is just a minor inconvenience, but for others, power outages can be deadly.
We have designed the electric grid with a great deal of built-in redundancy to ensure a high level of grid reliability, but it is simply not possible to plan for every possible contingency. Sometimes rare events will result in power outages.
There is no such thing as an electric grid where the power never goes out. An infinitely reliable grid would cost an infinite amount of money, and grid planners have had to make difficult trade-offs between reliability and affordability.
While Californians have become unfortunately accustomed to planned outages to prevent wildfires over the past year, the outages that California experienced this past weekend are a very rare type of power outage caused by a shortage of electricity supply. According to national grid planning standards, this type of outage should happen only one day in ten years. And in reality, these types of outages account for less than 0.01% of all outage hours nationally.
The jury is still out on whether California’s recent outages were caused by a grid planning failure, or if a series of unfortunate circumstances aligned to produce this extremely rare event. The next few days will help answer that question depending on how many more outages Californians experience.
In the meantime, here are some of the driving factors that have pushed California’s grid over the brink… along with a few solutions that could prevent this from happening again.
What factors led to the rotating blackouts?
It is already quite clear that a confluence of factors contributed to the rotating blackouts this past weekend. Energy industry folks (such as myself) will no doubt be studying California’s recent blackouts for some time to come. But here are a few factors that pushed the grid over the edge:
- Weather: Without question, the heatwave blanketing the western United States is historic. Though it’s not over yet, it has been compared to the deadly 2006 heatwave, and a National Weather Service meteorologist has stated that the intense weather patterns causing this heatwave happen only once every ten years. But of course, this is all complicated by climate change, which has already been warming the globe and changing weather patterns. So even if heatwaves of this intensity have only happened once every ten years in the past, they will be more likely in the future, and the grid should be better prepared. Electricity infrastructure and grid planning must account for climate change.
- Imports: Another important factor contributing to California’s rotating blackouts has been the lack of electricity imports from other states. The California Independent System Operator (CAISO), which operates the grid in 80% of California, has the ability to import more than 10,000 MW from its neighbors. However, with the rest of the western United States suffering from the same heat wave, California’s neighbors haven’t had very much extra electricity to send to California. While this factor is closely tied to the weather and evolving climate impacts, the amount of imported electricity California receives from its neighbors can be a determining factor in whether or not the grid operator must resort to rotating outages.
- Outages: Power plant and transmission line outages are another important consideration that can contribute to electricity supply shortages. For instance, the blackouts on August 15 were due, at least in part, to the unexpected loss of a large power plant. High heat can also make grid equipment, like transformers, more prone to failure, and reduce the capacity of transmission lines right when we need them most. Looking back on these rotating blackouts, we will need to examine all the other outages and the extent to which outages did or did not contribute to the electricity shortages.
This is by no means an exhaustive list. In the past few days, industry experts have also been voicing concerns about overly cautious grid operations and energy market issues, but without further investigation, it is too early to say how significant these other factors were.
What you can’t blame for the outages
Let me say that again: renewable energy is not the problem.
Renewable energy, particularly solar power, is playing a critical role in ensuring grid reliability during the day in California. The two rotating outages Californians recently experienced both started around 6:30pm, after the sun had set and solar power had largely tapered out. No one ever thought solar would somehow ensure grid reliability after the sun goes down, so blaming solar for these grid reliability issues is simply dishonest. On the contrary, solar has been shoring up the California grid and preventing outages earlier in the day.
However, the fact that these grid reliability issues have been happening in the evening hours does indicate a need for other forms of clean energy that can keep the grid reliable after the sun sets, which brings me to my next section.
How can California prevent similar outages from happening again?
There are two categories of solutions that could prevent this type of power outage from happening again: policy changes and grid resources, but the two go hand-in-hand. Policy changes influence the development of grid resources, so in reality, we will almost certainly need both types of solutions.
On the policy front, one of the most important solutions could come in the form of changes to California’s resource adequacy program. This program, which was created in response to California’s electricity supply shortages in the early 2000s, is the main tool ensuring the CAISO has enough electricity supply to meet demand. However, one significant blind spot of this program is that it focuses on peak demand, but most of California’s reliability problems happen closer to the net peak demand, which is the time when demand minus renewable generation reaches its maximum. In short, the resource adequacy program may need to be revamped so that it better ensures sufficient electricity supply when solar generation tapers out in the evening and the grid reaches the net peak demand. While it is still very early on in the process, the good news is that this restructuring of California’s resource adequacy program is already underway.
By itself, making changes to resource adequacy rules is not going to stop rotating blackouts from happening again—we would need new grid resources as well. These grid resources could either increase the electricity supply or reduce electricity demand during the evening hours when reliability challenges are most likely to occur. And California is already making some progress on this front.
For example, the state’s electricity providers will be adding thousands of megawatts of energy storage to the grid in the next couple years, which will help provide electricity when the grid needs it most. However, much of that energy storage is meant to replace a few very old and environmentally harmful natural gas power plants, so California may need to speed up its investments in energy storage and other forms of renewable energy even more.
On the other side of the equation, investments in grid resources that reduce load are also badly needed. This includes everything from energy efficiency to demand response to distributed energy resources. California will need to take all of these approaches to making a modern grid that ensures reliability during the transition to clean electricity.
It’s going to get hotter, so we need to get cleaner
With climate change intensifying horrific heatwaves throughout the west, along with the fact that electricity generation still makes up 15% of California’s global warming emissions, it is all too apparent that we need to reduce electric sector global warming emissions and transition to clean sources of electricity, fast. All of us—those privileged to have air conditioning, jobs, safe housing, health, and those of us in more vulnerable situations— face worsening climate impacts in the coming decades. Thankfully, the California Legislature set a goal in 2018 to achieve 100% clean electricity by 2045. As we make this transition, we will have to learn how to keep the grid reliable with even higher levels of renewables because continuing our heavy reliance on fossil fuels that are dangerously warming our world is simply not an option.
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