With the Eastern U.S. already facing a possible heat wave this weekend, the nation's power grid regulator has a dire warning: Large swaths of the country are at risk of blackouts this summer as climbing temperatures cause surging demand for energy.
In its annual summer assessment released this week, the North American Electric Reliability Corporation noted that the Upper Midwest is facing a capacity shortfall leading to a "high risk of energy emergencies." The entire Western U.S. also could face a power outage emergency in the event of spikes in energy use.
"We've been doing this for close to 30 years. This is probably one of the grimmest pictures we've painted in a while," John Moura, NERC's director of reliability assessment and performance analysis, told CBS MoneyWatch.
A hotter-than-expected summer means more people would need more power to cool their homes and offices, while the high heat and drought drain the electricity supply.
"Both the extreme heat and drought conditions can take a lot of generation out of service," said Rob Gramlich, president of Grid Strategies, a consulting firm specializing in renewable energy.
Drought conditions across much of the West means less water available for hydroelectric power. Drought also affects power plants that run on coal, gas or nuclear power, which create heat and need water for cooling.
"Extreme heat leads to increased chances of mechanical failure for conventional power plants," Gramlich said.
West, Midwest on high alert
NERC is also watching out for a potentially heavy wildfire season in much of the West, which threatens power transmission lines and, because of smoke, reduces the amount of electricity created by solar facilities.
"If a power line goes down because of a fire, then there can be localized areas that have shortfalls of power. It could be like half a state or could be half a neighborhood," Gramlich said. "And they're obviously very hard to predict."
But the most affected parts of the country might be the Midwest, NERC warned. In a large swath of the grid stretching from Illinois to Minnesota, the summer's power demands are projected to exceed the grid's capacity. That's because this area of the grid — known as the Midcontinent Independent System Operator, or MISO — has lost about 2% of its generation capacity since last year as plants have retired; a key transmission line is also down for maintenance.
Moura said that while more capacity was being added to the grid, largely in the form of wind and solar, older fossil fuel plants were being retired faster than they could be replaced. Meanwhile, blistering summers are pushing up peak energy demand ever higher.
"As extreme weather continues to plague us, we've really noticed that extreme weather doesn't really mean rare weather," said Moura. "We've seen the extremes happening more often. You have to plan to have more resources available just in case."
Still, the assessment doesn't mean Midwesterners should start panicking. NERC warned last year that nearly 40% of the U.S. population was at risk of blackouts, but most of the grid, except for the Northwest, remained unaffected, Bloomberg reported.
What people should expect is increasing pleas from utilities to conserve power as earlier and more frequent heat waves strain the grid. Earlier this month, Texas' grid operator pleaded with residents to cut power use after six power plants unexpectedly shut down. MISO told residents to expect "temporary, controlled outages" this summer.
Double the number of blackouts
Strengthening the grid would require bringing on more power-generating resources and possibly keeping older plants running longer, as well as increasing connections between regions to make power easier to transport.
As more renewable power is built, utilities and regulators can also manage it better by installing more batteries and incentivizing customers to shift when they use power to avoid overload, said Gramlich of Grid Strategies.
"The problem is, we all use electricity at the same time. But we don't have to. We don't have to be charging our electric vehicles when we need air conditioning at four in the afternoon," he said.
If the U.S. doesn't manage that transition successfully, we're facing the prospect of more severe and more frequent blackouts, with potentially deadly consequences.
Recent research by Brian Stone, a professor at the Georgia Institute of Technology who studies urban climate change, shows blackouts have increased in recent years.
"There's been a doubling in the number of blackouts per year in the last five years, and the majority of the blackouts are happening in the summer, in warm weather," he said.
"Most summers these days are the hottest summer ever. What overlays that is just a creeping risk of antiquated infrastructure … and those trends are converging at the wrong time," Stone said.
Of all the types of damage wrought by climate change — hurricanes, floods and fires — Stone believes the danger posed by heat waves is the most underestimated.
"In a city like Phoenix, air conditioning is life support for people, and if you have a disruption, that's a tremendous vulnerability," he said. "I characterize it as the greatest health-related threat that climate change poses to this county — a blackout during a heat wave."
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