4 takeaways from the grid’s record-breaking summer

Source: By Jason Plaut, E&E News • Posted: Sunday, August 27, 2023

Hot temperatures have tested the U.S. power grid this summer.

Claudine Hellmuth/POLITICO (illustration); Andrew Martin/Pixabay (power lines); Lindsey White/Pixabay (thermometer); PublicDomainPictures.net (sun flare)

Grid monitors issued dire warnings ahead of the summer that Americans could face blackouts during an extreme heat wave — but so far, that hasn’t happened.


There isn’t a simple answer for the grid’s stability despite record-breaking heat — new wind turbines, solar panels and batteries played a major role on the hottest days, but gas and coal plants remained a bedrock. Grid operators and utilities say they’re better prepared for extreme weather. And there was a dash of luck, suggesting that the outcome could have been worse.

There’s also still plenty of summer to go, and there are signs of strain.

A heat dome continues to scorch the Midwest and Southeast. The grid operators Southwest Power Pool (SPP), which covers parts of 15 states, and the Electric Reliability Council of Texas (ERCOT) issued alerts this week signaling tight conditions. On Thursday, the Midcontinent Independent System Operator (MISO) covering the central U.S. announced an emergency event requiring generators to take additional steps to meet demand but didn’t institute rolling blackouts.

Mark Olson, manager of reliability assessments at the North American Electric Reliability Corp. (NERC), a national grid watchdog, said the lack of widespread power outages or brownouts so far amid conditions he called “uncharted territory” doesn’t mean that the U.S. grid is fully ready for the onslaught of climate change.

“We’re seeing the grid operating at the outer limits of its capability,” said Olson. “Fortunately the operators are able to get through, but we’re seeing the creaks and groans. We should all take these signals to heart.”

With hotter summers predicted for the future, additional factors could come into play, such as climate conditions that hinder wind and solar output and spiking power demand from more use of electric vehicles and appliances.

Here are four questions answered about the U.S. grid’s performance this summer:

Are renewables saving the day?

Not unilaterally, but they’ve played a major role.

At the beginning of August, the U.S. had some 237,000 megawatts of utility-scale solar, wind and battery storage online, up 12 percent from the same time last year, according to the American Clean Power Association. Of that, 10,000 MW was added in the first half of 2023.

With that kind of volume, it’s not surprising that renewables are playing a bigger role than ever in keeping the lights on, since they make up a larger portion of the grid. But supporters say it’s also how renewables are performing that matters.

“It’s become increasingly clear that renewables, along with enabling technologies like energy storage, are providing a more resilient source of power through the increasingly frequent weather extremes that we see with the changing climate,” said Gregory Wetstone, CEO of the American Council on Renewable Energy.

Take Texas, which now hosts the most low-carbon energy capacity in the country. Ahead of the summer, ERCOT, which covers 90 percent of the state’s load, said the grid could plunge into chaos at peak demand if there were outages totaling 11,000 megawatts from coal, gas and nuclear plants.

Those types of plants saw outages ranging between 8,000 and 10,000 MW during a heat wave earlier this summer, and demand was higher than forecast. Wind and solar, however, produced as expected, on some days accounting for as much as a third of the grid’s needs.

One MW can power about 200 homes during periods of peak demand in ERCOT.

Crucially, wind and solar in Texas — and elsewhere — are working in tandem, said John Hensley, vice president of research and analytics for the American Clean Power Association. Solar has been charging under the hot sun, and wind has stepped up in the evening hours when the sun has gone down and demand is still high. A surge of battery storage has also helped dispatch clean-generated power later into the evening.

According to Grid Status, which tracks power grids, all of the country’s power grids have set solar generation records this summer. This week, as SPP set all-time maximum load records on three consecutive days, renewables were contributing between 10 and 20 percent of generation at peak times, largely from wind.

Several grid operators — including the California Independent System Operator and MISO — also set records this spring for the ratio of renewables serving electricity load.

Hensley said that renewables’ big role this summer should help address the “skepticism and concern” that more wind and solar means sacrificing reliability.

“We’re proving that narrative wrong,” said Hensley.

How much of this was luck?

It’s difficult to say, although luck has been important as grid operators benefited from seasonal conditions that they may not be able to count on in the future.

For example, a relatively temperate spring meant that grid operators and asset owners were able to do routine maintenance on power plants and transmission infrastructure. A wet winter meant there was ample hydropower production in the Northwest and Southwest, a factor that led California to be confident about adequate power supplies this summer.

The wind has also been especially strong in parts of the country, which is not always guaranteed during a heat wave and could actually become less likely as the Earth warms.

Some studies have shown that climate change could cause more wind lulls, which are times when the wind doesn’t blow. Other research has said there could be more extreme gusts with climate change that could damage turbines, transmission lines and power poles.

Julie Lundquist, a professor of Atmospheric and Oceanic Sciences at the University of Colorado, Boulder, said in an email that there is “no clear consensus” about what will happen to wind resources under climate change. However, she added, that doesn’t mean that wind will simply lose its value.

“My personal perspective is that wind energy technology will be changing and evolving, so even if winds slow down slightly, the technology will improve so that we will still be able to rely on wind as part of our energy portfolio,” Lundquist said in an email.

NERC’s Olson said the summer was also a sign that “you make your own luck and reap the benefits.” Grid operators who were able to do routine maintenance on transmission infrastructure and power generators were better prepared for a grueling summer, he said. But as climate change accelerates, operators may no longer be able to rely on having a temperate spring season.

Clean energy groups say the need to adapt should come with new investments to support the grid. More energy storage can help avert dips in renewable production. Investments in transmission can help regions share resources, making individual parts of the country less dependent on weather without relying on fossil fuel plants.

“It’s hard to argue that at this point we need a 21st century grid to be able to withstand the reality of 21st century weather,” said Wetsone.

What does this summer tell us about fossil fuels?

It’s not unusual for gas and coal plants running at full throttle in extreme heat to break down, and some did buckle as expected this summer. But fossil fuels still accounted for a large share of the country’s power.

According to data from the U.S. Energy Information Administration, natural gas remained the top source of power generation across the country and accounted for a larger share of electricity than last summer. Research from data firm Refinitiv found that the gas share of power from January through mid-August was 42.4 percent, compared to 38.9 percent in the same time period in 2022.

After gas, coal and nuclear have been the second- and third-most productive sources this summer.

That means fossil fuels have shown their worth in balancing wind and solar at times when the wind is not blowing and the sun is not shining, said Scott Aaronson, vice president of security and preparedness for the Edison Electric Institute, which represents utilities.

“It sounds like a talking point when someone says ‘all of the above,’ but we genuinely benefit from an ‘all of the above’ strategy,” Aaronson said. “Each resource has its benefits and drawbacks, … but taken holistically, they make for a much more resilient grid.”

As the grid transitions, some experts and power providers have said it’s important to keep quick-start fossil fuel power plants online to ensure reliability.

A June report from NERC warned that the grid can’t manage accelerated retirements of coal and gas plants at the same time, since wind and solar may not hold up in extreme weather.

The nation’s grid “has never been more dependent upon round-the-clock continuity of just-in-time natural gas delivery,” that report said.

The Texas Oil and Gas Association has pushed back on the notion that renewables were saving that state. In an August release, Dean Foreman, the group’s chief economist, wrote that the gas sector’s performance underscores why it “remains the backbone of the ERCOT power grid and is indispensable in powering modern life.”

What else can be done to prevent blackouts?

As 2023 smashes heat records left and right, some utilities say they’re planning for conditions like this summer’s to be the new normal. Rather than a day or two where ratepayers are cranking their air conditioning and pushing the grid to its limits, operators are planning for those conditions for long stretches. They are leaning more on tools such as demand response programs, which encourage customers to turn down their power use during peak times.

For example, Arizona Public Service Co., the state’s largest utility, broke its demand record seven times during a period this summer when temperatures exceeded 100 degrees Fahrenheit, said Justin Joiner, the utility’s vice president of resource management. The utility is now thinking differently about how much it needs to prepare for heat.

“In that past, you’d think of one hot summer as an anomaly. You’d expect to see one especially hot day or week, then it returns to normal,” said Joiner. “What we’re seeing now is a trend, not an anomaly. We’re adjusting accordingly, and we are constantly revisiting our projections.”

With that in mind, the utility is now planning for higher peak loads and securing stronger reserve margins, essentially finding ways to get even more power than needed just in case of outages or unexpected spikes in demand. That includes ramping up battery storage as well as demand response.

Some grids are also looking to virtual power plants, which allow customers to pool their small home batteries and electric vehicles to work as larger grid resources.

A May 2023 report from the Pacific Northwest National Laboratory said that with climate change accelerating, “historical averages may no longer be sufficient for resource planning” and recommended that utilities consider “multiple scenarios … including those outside traditional history-based scenario analysis” to craft plans.

Operators may also need to think independently, since state-spanning heat waves can reduce the ability to import energy that has traditionally offered help.

With climate change expected to make heat waves more common, longer and more intense, grid operators will have to continue planning for more summers that look like this, said Michael Craig, an assistant professor in energy systems at the University of Michigan who studies the impact of climate change on energy systems.

“All these grid operators are making huge changes around decarbonization, now climate change layers more complexity on top of it,” Craig said. “For example, you have to think about how to stress test systems not just for the peak temperatures we’ve seen historically, but what we could see in the next five or 10 years.”