Record heat tested US power grids. Energy expert Doug Arent explains how they withstood the challenge

Record heat tested US power grids this summer, driving electricity demand to unprecedented levels. Meanwhile, some of the fastest-growing sources of power – solar and batteries – were breaking records of their own.

When a historic heat dome settled over the eastern United States in July, grid operators braced for the worst. The US Department of Energy warned 17 states to prepare for blackouts. PJM Interconnection – the nation’s largest regional grid which covers parts of the Midwest and East Coast – was instructed to pull data centers onto backup power like diesel generators as a “last resort.”

But even as demand across the region reached its highest level on record, backup supply wasn’t needed. The US power grid delivered more electricity than ever, due to clean energy’s massive growth, as reported by Canary media.

In New England, new offshore wind farms and a transmission line of Canadian hydropower helped the region burn less oil than it had during a comparable heatwave the year before.

Meanwhile, in Texas, the Electric Reliability Council (ERCOT) recorded peak load exceeding 91 gigawatts. But the grid also set records for solar production (34,700 megawatts) and battery storage discharge (12,000 megawatts). Two years earlier, Texas had less than a quarter of today’s battery capacity.

The Climate Champions spoke with Doug Arent, advisor to the Coordinating Council for the Acceleration of Expansion and Resilience of Grids, about how energy systems are rapidly changing – with more renewable generation, more battery storage and new transmission coming online even as demand and extreme weather increase.

US power grids faced record demand, but still held up despite emergency warnings. What do you think the energy industry is getting right?

A lot of it comes down to timing and good planning. You have the most extreme heat during the day, which is the heavy air conditioning load time, and that's coincident with the availability of solar. But most people still run air conditioning in the evenings too, and that's where storage comes in now: it helps carry that evening load (energy demand) through the system. Wind power typically picks up more in the evening as well.

You're also seeing a lot of battery storage coming online, because of the value it brings to the grid: the ability to absorb renewables when they're available, and dispatch them when they're needed.

The key thing also is that US grids have headroom (spare capacity to draw on beyond normal demand) to deal with extreme days which is a real credit to grid planners. We should recognize that the grid planners are doing a good job, and we should heed their advice to plan for such extremities.

What is driving utilities and states to add so much renewable generation and storage? Is it policy, economics or something else?

It's largely economics. A lot of electricity policy is actually driven by states, not the federal government. Where states have stayed fairly consistent with their policies, you see steady progress. The economics are very positive for continuing to evolve the electricity system toward least-cost resources, and that logic holds regardless of who's in power federally.

Utilities bring states their resource plans, and those plans increasingly show that new wind, solar and batteries – and in some cases natural gas – are the least-cost way forward, even without federal tax incentives. Coal is old and out of the money. Nuclear is decades away. So to meet new load, renewables are the preferred pathway.

Trusting the market, but having well-functioning planning processes, is a really powerful combination. Texas is a classic example. They do well-structured grid and load planning, especially with data centers coming, and they're very methodical about it. They aren't seeing high energy prices, because they're able to develop low-cost wind, solar, and battery resources along with transmission and some new natural gas. They continue to have a very clean grid.

You've said the biggest shift may be in what we know. What do you mean?

Everyone's always talked historically about the policy, technology, finance triangle. It’s important to expand that to include knowledge, and social and institutional factors, as I explain in my book “Our Renewable Energy Future”. We often don’t recognize that knowledge has changed a lot. We now know how to operate grids with lots of renewables in them. We should be leaning in much more heavily to think about what our grids look like for the 22nd century and to address not just mitigation, but adaptation, as we go forward.

Europe has also faced several difficult summers with some countries experiencing energy blackouts. Why are some systems more vulnerable to extreme heat?

When it gets really hot, grids aren't able to carry as much power as when it's cooler. There's something called line sag – the lines actually heat up. So heat waves do two things: they reduce the capacity of the grid, and they increase the load where there's additional air-conditioning demand.

Europe overall has had more congested grids, which means less overall headroom for meeting new demand. So, when the headroom goes down even further because it's hot, they have to manage it more carefully. They don't want a repeat of what happened in Iberia last year, when a cascading failure took down the entire Spanish and Portuguese grid for tens of hours. The heat waves this summer are a wake-up call on how to address extreme heat, or rather extreme weather. Remember Storm Uri, the 2021 freeze that knocked out power to millions of Texans and killed hundreds? That was the same lesson, but from extreme cold.

We need to prudently plan for increased extreme events, which we know from climate change are increasing in frequency and duration. We need to continue to evolve our resiliency.

The COP31 Presidency has set a "35 by 35" direction for electrification. What excites you about where this is heading?

What excites me is the enhanced attention to the importance of electrification, in particular with domestic, principally renewable resources. But also hydro or, for some countries, nuclear as a low-carbon option, to deal with the security side of energy imports.

It's the renewed recognition that electrification is part of a strong energy-security, climate, affordability, and productivity agenda, and the fact that we've now built knowledge over the last 20-30 years about how to do it much more quickly. We can help countries meet those goals rapidly and affordably. They don't have to build a grid of the 1900s. We should help them build a grid for the 2200s.

You advise the Coordinating Council for the Acceleration of Expansion and Resilience of Grids. Where does that fit within the broader Global Climate Action Agenda?

The Coordinating Council grew out of a request from Brazil to create a way to implement the grids and storage goals. Remember, COP28 set the headline targets (tripling renewables, doubling energy efficiency) and COP29 followed with the pledge on energy storage and grids. You had the goals, and you had lots of organizations touching different pieces of it, but there was no implementing body pulling it together and supporting countries directly. That's the gap the Coordinating Council fills.

The Champions and the Action Agenda exist to mobilize the non-state actors – the companies, the cities, the institutions, the technical organizations – around the goals that governments set, and to help turn commitments into delivery on the ground. The Coordinating Council is one of the mechanisms for that on grids and electrification specifically.

The whole idea is to leverage that network of knowledge and capabilities, and deliver targeted technical assistance and support to countries in service of their strategic electrification goals. For example, improved planning processes for the buildout and utilization of grids. Last June, the Coordinating Council unveiled a ten‑point plan to strengthen energy security and protect consumers, and is offering technical assistance to support its implementation.

That's the core backbone for electrification in any country. Get the planning and the grid right, and the renewables, the storage, the electrified demand, all come together.