Is the power grid getting more able to withstand extended heat waves, like the one that baked New Jersey with temperatures above 90 degrees for at least seven consecutive days last week?
That's a question some are asking in the wake of the summer surge that saw heat indexes topping 100 degrees for several days, but relatively few power outages and fewer frantic calls on customers to conserve energy to avoid potential brownouts.
In the opinion of energy executives, power grid operators, and analysts, that performance can be traced to several factors, which reflect ways the energy sector has promoted reliability in recent years.
They include increased demand-response to have big users of energy cut back their usage during peak periods; a boost in distributed generation, such as the 1,100 megawatts of new solar systems that have been installed in New Jersey over the past decade; and more aggressive efforts to cut energy use through conservation and energy efficiency.
“It’s a probably a combination of everything,’’ said Ray Dotter, a spokesman for PJM Interconnection, the operator of the nation’s largest power grid, which includes New Jersey.
“It was really hot and hot for a long time as well as there were high prices,’’ noted Paul Patterson, an energy analyst with Glenrock associates in New York. “The question is what is going on in the market. Is it demand-response, distributed generation, or other factors?’’ he asked.
Typically, electric utilities experience problems the longer a heat wave goes on. “They used to call it the three-day effect,’’ Dotter said. As the heat wave progressed, the power grid would come under more stress, leading to additional calls for industry and consumers to reduce their power use, he said.
During last week’s heat wave, the peak-demand day for PJM was Thursday, when power suppliers delivered 158,156 megawatts of electricity to customers, well below the peak-demand day registered in July 2011, when it hit 165,492 megawatts. Instead of growing each day, however, the peak demand during the recent heat wave remained relatively flat, according to Dotter.
To some, the ability of the power grid to weather the heat with relatively few problems suggests some of the more expensive projects undertaken to make the system more reliable may not have been needed.
“Load growth is slack and it is going down because of distributed generation,’’ said Dennis Wilson, president of Renewable Power Inc., a solar and energy efficiency firm based in Parsippany. He cited the huge amount of solar installations built around the state.
Wilson questioned whether the controversial Susquehanna-Roseland transmission line, a high-voltage power line cutting through three national park systems in the New Jersey Highlands with an eventual cost of $1 billion, including its Pennsylvania extension. Advocates of the power line said it would decrease congestion on the power grid that cost consumers in the state more than $1 billion each year.
“Was this really needed?’’ asked Wilson, calling the transmission project a “last-gasp’’ effort by the utility to lock-in guaranteed returns on its investment.
Dotter disagreed, noting the reliability provided by the Susquehanna-Roseland project might not have been needed this past few weeks, but it eventually will enhance the reliability of the grid once it is in operation, which is expected to occur in June 2015.
But Jeff Tittel, director of the New Jersey Sierra Club, argued otherwise. “It shows the market is working better than the BPU,’’ he said, citing subsidies handed out by the agency to promote development of new natural gas plants to provide additional generating capacity in the state, a development that might not be needed in the wake of recent developments.