Power Grid Keeps Its Cool Despite Being Hammered By The Heat

Tom Johnson | August 15, 2016 | Energy & Environment
Aside from an occasional glitch, the grid has consistently delivered power to customers despite exceedingly high demand

transmission heat
The power grid has weathered the latest brutal heat wave pretty much the way it has performed most of the summer, providing electricity to tens of millions of customers with only an occasional glitch.

No brownouts. No emergency calls for conservation, especially for big energy users. No milestones in achieving record peak-demand for electricity. This year may be on pace to set another record for hottest year ever, but it has yet to test the nation’s largest power grid.

The lack of problems can be traced to a number of factors that have occurred in the past few years, according to energy executives. They include increased investments in transmission projects and new, more-efficient gas-fired power plants replacing retired coal units.

This past Thursday, PJM Interconnection recorded the 11th-highest peak load for electricity ever, but Mike Bryson, vice president of operations, said executives were “comfortable’’ with how the system was performing despite the high temperatures.

On Friday, PJM issued a hot-weather alert for the Mid-Atlantic region continuing through the weekend, including today. The scorching heat led Public Service Electric & Gas to forecast it would approach its Sunday summer peak, attained 11 years ago yesterday, when it reached 9,310 megawatts.

Its system, however, was showing few strains. Heat-related outages were isolated and primarily due to transformer failures, which can occur when they become overloaded.

Like others, Bryson attributed enhanced reliability of the grid to upgrades to the transmission system that reduces congestion by moving power from one area to another. Bryson also said the grid is benefitting from the growing penetration of solar systems to deliver electricity and greater reliance on programs to cut electricity use.

“Energy efficiency has a lot to do with it,’’ Bryson said. In the past few years, electricity use has flattened out, not rising as fast as it has in the past.

Ron Wharton, senior director of electric operations for PSE&G, agreed. “We’ve been able to import more power into load pockets to serve customers,’’ he said, referring to an improved transmission system. “Investments in transmission are a key driver for us.’’

He also cited three new natural-gas power plants that have come online in New Jersey over the past few years. Two more are expected to become operational in the next couple of years. He, too, said increased energy efficiency and solar have helped ease demand.

One other factor also has helped offset the heat — its timing. Like another heat wave that blanketed the state in late July, the brunt of the wave occurred over the weekend when most people are off work and electricity demand falls, officials said.

Despite the high temperatures, PJM has not relied on demand response — which is when customers voluntarily reduce their energy usage at times of peak demand or high prices — to help maintain reliability.

“Every day like today, just a couple of years ago, we would have called out an emergency demand-response,’’ Bryson said. Under that scenario, some customers would mandatorily reduce their energy use up to a certain level to help maintain grid reliability. PJM has not issued such a call since 2013.

Lower wholesale electricity prices, however, have made customers less willing to shut down a portion of their operations — even if they receive payments for doing so.

The grid operator also relies on economic demand-response, in which customers voluntarily reduce use. One example is air-conditioning cycling programs; customers agree to have their units run less efficiently to reduce demand on the grid. Operated by utilities, they can achieve huge energy savings. In Baltimore, an air-conditioning cycling program has lowered usage by 400 megawatts to 500 megawatts, equivalent to a medium-sized power plant.