This summer, extreme heat is hitting the US—hard. Take the recent Western heat dome, which raised temps up to four degrees above previous records. That’s “extremely hard to do statistically,” Erik Smith, a climate data analyst at EPRI, told Energy Central. “And research says that we’re going to see a lot more of those types of record-shattering events.”
What this means for the grid: These unprecedented heat waves pile more demand on an already strained system. And in these extreme conditions, it’s hard to keep essential assets running.
One of the greatest challenges? Ensuring nuclear plants can keep on splitting atoms. They are “very risk-averse,” Smith told us. These facilities rely on nearby rivers, oceans, and lakes to cool off reactors (and discharge the leftover water)—so high temps can throw off the entire delicate equation. Just look at France, where nuclear plants are currently cutting production to avoid sending hot water into already hot rivers.
Other heat hurdles:
Solar generation suffers: You’d think that a scorching, cloudless day would yield plenty of solar output. But PV panels are designed to perform best at around 77 degrees Fahrenheit. For every degree above that threshold, power output drops by roughly 0.5%.
Storage capacity sinks: Lithium-ion batteries operate best at around 59–95 degrees Fahrenheit. Temps above that can reduce storage capacity over time. And when facilities turn up the AC to protect batteries, it reduces the overall output.
Natural gas plants lose efficiency: Gas turbines operate best at 59°F. For every 33.8°F (1°C) temperature increase above that baseline, they lose 0.1% in thermal efficiency and 1.47 MW of power output.
Extreme temps can also reduce transmission conductor capacity, age transformer insulation, and accelerate underground cable corrosion.
The best way to keep on generating gigawatts during extreme heat? Accurate and ample weather forecasting, which helps operators prepare for whatever comes next. (One bad sign: The Trump administration's National Weather Service staffing cuts are limiting the launches of trusty weather balloons…)
Right now, we’re in the midst of a strong El Niño, which brings a higher likelihood of searingly hot days—but also a silver lining: more predictability. “So there’s a lot more that you can do earlier on,” Smith said.