NEI says domestic nuclear plants didn’t wilt during heat wave

U.S. domestic nuclear plants have cranked out reliable electric generation while eastern states have recently suffered under this summer’s second major heat wave, the Nuclear Energy Institute (NEI) said Aug. 18.

During the first two weeks of August, the U.S. nuclear industry’s average availability factor was 96.5%, NEI said in a statement. Availability factor measures how much of a plant’s output is available to produce electricity.

Recent weeks have seen record temperatures grip the nation as a “heat dome” has descended over most of the continental U.S. While it isn’t news that summer is hot, it is when the temperatures are 15-20 degrees higher than average for this time of year, NEI said in a related Aug. 1 blog posting.

As temperatures across the Northeast pushed past 90 degrees on Aug. 11, New England’s regional transmission organization ISO New England (ISO-NE) recorded a three-year summer record for electricity demand across the six-state region whose bulk power generation and transmission it oversees, NEI said.

The New York region’s counterpart, New York Independent System Operator (NY ISO) also saw its peak load demand rise above forecasts. In the Midwest, the Midcontinent Independent System Operator (MISO) issued a temporary reliability threat alert when a large coal-fired power plant in Michigan went off-line indefinitely after a major fire—MISO had already declared a hot weather alert and “conservative operations” for all of Michigan.

On the morning of Aug. 11, during the beginning of the latest heat wave, the Dominion (NYSE:D) 918-MW Millstone 2 nuclear reactor in Connecticut incurred an unplanned two-day outage. The shock to an already tight situation caused ISO-NE to declare a capacity shortage alert as real-time power prices surged from about $40 per megawatt-hour (MWh) to more than $100 per MWh within a half-hour of the plant’s manual shutdown and above $2,500 per MWh by midafternoon peak load, NEI said.

ISO-NE scrambled to bring in peak-load generation from other sources, including from oil-fired and hydroelectric plants that are normally kept on reserve.

Millstone 2 returned to 100% availability Aug. 13. After the large price spikes of the previous two days, “hourly locational marginal prices and reserve prices returned to normal levels, displaying a system that was not under stress and with sufficient margin,” NEI Manager of Energy and Economic Analysis Michael Purdie said.

NEI touted nuclear power as a more reliable source of energy than renewables.

While solar power obviously does better in the summer months, the availability of wind power notoriously falls off during this time, NEI said in its statement, citing a 2015 study by the Electric Reliability Council of Texas (ERCOT).

The robustness of nuclear facilities in the face of extreme weather is reflected in last weekend’s hard rains and flooding in Louisiana, The Entergy (NYSE:ETR) River Bend and Waterford nuclear power plants kept running at 100% capacity, NEI said.

About Wayne Barber 4201 Articles
Wayne Barber, Chief Analyst for the GenerationHub, has been covering power generation, energy and natural resources issues at national publications for more than 20 years. Prior to joining PennWell he was editor of Generation Markets Week at SNL Financial for nine years. He has also worked as a business journalist at both McGraw-Hill and Financial Times Energy. Wayne also worked as a newspaper reporter for several years. During his career has visited nuclear reactors and coal mines as well as coal and natural gas power plants. Wayne can be reached at