By - Jim Vess

Regional grid operators brace for summer peak demand as hot weather is forecast

Energize Weekly, May 23, 2018

Regional grid operators are bracing for a hotter-than-normal summer, but say they are prepared to meet peak demand.

PJM Interconnection, the nation’s largest grid, covering parts of the mid-Atlantic region and the Midwest, said it expects a summer peak of 150,000 megawatts (MW) as the National Weather Service is predicting above-normal temperatures in the District of Columbia and the 13 states served by the regional grid.

“PJM continues to ensure that the power supply is secure and reliable while maintaining efficient and transparent markets that save billions of dollars for our customers,” Andrew L. Ott, PJM president and CEO, said in a statement. “We have planned and prepared for summer operations and we have plenty of reserves to meet the demand.”

The demand last summer peaked at 145,331 MW on July 19. PJM’s all-time highest power use was 165,492 MW in summer 2006.

PJM has reserve resources to cover generation that is unexpectedly unavailable or demand that is higher than forecasted, the operator said. PJM’s required reserve is 16.1 percent of the forecasted demand level. This summer, PJM’s expected reserve margin is more than 28 percent, or nearly 41,000 MW.

PJM has 184,010 MW of installed generating capacity. One megawatt can power about 800 homes. There are 65 million people served by the PJM grid.

The Midcontinent Independent System Operator (MISO), which serves 42 million customers in all or parts of 15 states and the Canadian province of Manitoba, said it expects its summer demand to peak at 124,700 MW, considerably below its available capacity of 148,600 MW.

MISO has projected adequate power reserves to meet 2018 summer peak demand. The regional transmission organization expects summer demand to peak at 124.7 gigawatts, with 148.6 GW of available capacity.

“MISO capacity levels exceed our 2018 summer peak forecast and our reserve margin requirement,” Clair Moeller, MISO president and chief operating officer, said in statement. “The work of the load-serving entities, states and local jurisdictions continue to help ensure adequate resources to meet the region’s power needs.”

MISO has a 2018 base reserve margin of 19.1 percent as a result of the combination of declining load forecasts by utility companies, increases in demand response programs, which reduce electric use during high demand periods, and more distributed generation of electricity from sources such as rooftop solar coming from households and businesses.

Warmer-than-normal summer temperatures are predicted for much of the midcontinent region, and sustained high temperatures can have an impact on day-to-day operations, MISO said.

“MISO continuously works to improve and implement procedures and processes to monitor situations and proactively address challenges—such as extreme weather situations—throughout the year,” Moeller said.

ISO New England (ISO-NE), which serves 14.4 million people in six states, said that under normal summer conditions, with temperatures around 90 degrees Fahrenheit, demand would peak at 27,729 MW.

If the region is hit with an extended heat wave where temperatures average 94 degrees, peak demand would rise to 28,120 MW. ISO-NE projects its available capacity to be 32,000 MW.

“If operating conditions become tight under these circumstances, the ISO has well-established procedures in place to maintain reliable power system operations,” the operator said.

A total of 1,630 MW of new generating capacity is expected to be available during the summer, including two new natural gas-fired power plants and one new dual-fuel plant that total about 1,490 MW.

Last summer, demand for electricity peaked on June 13, 2017, at 23,968 MW. The all-time record for peak demand was set on Aug. 2, 2006, when demand reached 28,130 MW after a prolonged heat wave. New England summer peaks are driven by consumer demand for electricity for air conditioning.

ISO-NE will also become the first U.S. grid operator to fully integrate demand response resources into its daily energy dispatch and reserves. It estimates that about 408 MW of demand response resources will be available.

The California Independent System Operator (CAISO), serving about 40 million people, projects a 0.09 percent drop in the 1-in-2 peak demand from the 2017 of 46,669 MW. A 1-in-2 peak means there is a 50 percent chance of demand being higher or lower with normal weather conditions.

The 1-in-10 peak, assuming extreme temperatures, is forecast at 51,632 MW. CAISO’s all-time peak was 50,116 MW in 2017.

CAISO said it faces a significant risk of encountering conditions that could result in operating reserve shortfalls as a result of lower hydro conditions and the retirement of 789 MW of dispatchable gas generation that had been available in prior summers to meet high load conditions that persist after the solar generation ramps down in the late afternoon.

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