Sept. 24 (Bloomberg) -- Spot wholesale electricity surged to a 15-month high in southern Texas as local supplies dropped while demand across the main state grid topped forecasts.
The Electric Reliability Council of Texas Inc. raised its peak-demand outlook for today by 5.1 percent to 56,705 megawatts from the day-ahead projection of 53,965, according to its website. The high temperature in Houston today may be 93 degrees Fahrenheit (34 Celsius), 6 above normal, and Dallas may be 7 higher than average at 93 degrees, data show from AccuWeather Inc. in State College, Pennsylvania.
Houston spot power topped $1,500 a megawatt-hour while regional transmission bottlenecks bolstered prices across the rest of the state. The shutdown of two coal-fired units at NRG Energy Corp.’s W.A. Parish power plant reduced relatively cheap generation supply in the south, according to Genscape Inc., which tracks real-time grid data.
“We have seen some temporary price increases following generation losses as additional generation comes on line,” Robbie Searcy, spokeswoman for Ercot in Austin, said in an e- mail. “We also have seen some congestion-related costs in some regions.”
Spot on-peak prices for Houston surged $252.79 to $290.20 a megawatt-hour as of 4 p.m., heading for the highest daily average since June 26, 2012, grid data compiled by Bloomberg show. The average price across the Ercot region more than tripled to $103.85 a megawatt-hour.
Relatively strong demand and a drop in supply in Houston versus the North are contributing to transmission bottlenecks between the regions, said Ken Lysik, a Boston-based analyst with Genscape. Two coal-fired units with 1,100-megawatts of capacity at NRG’s Parish plant went offline on the night of Sept. 22.
“Parish is cheap baseload coal and those units are still offline today,” he said.
David Knox, a spokesman for NRG in Houston, declined to comment on the plant’s operational status, following company policy, according to an e-mailed response. Ercot has sufficient generating capacity available to meet today’s anticipated demand, Searcy said.
Electricity prices also gained in New England amid lower nuclear generation and higher demand.
Entergy Corp. cut output at its Vermont Yankee plant, about 80 miles (129 kilometers) northwest of Boston, to 29 percent of capacity from full power yesterday, Nuclear Regulatory Commission data show. The unit’s nameplate capacity is 563 megawatts, according to the Energy Information Administration.
Power consumption on the six-state grid stretching from Maine to Connecticut was 15,037 megawatts at 2:47 p.m. Eastern time, up 1.2 percent from the same hour yesterday, ISO New England Inc.’s website showed.
Spot on-peak prices for Boston rose $6.07, or 21 percent, to average $34.58 a megawatt-hour as of 5 p.m. from yesterday’s average, grid data showed.
Boston on-peak power traded at a premium of $1.56 to New York City prices versus a discount of $3.41 yesterday. New York prices were little changed, gaining $1.10 to $33.02.
Prices rose on the 13-state grid operated by PJM Interconnection LLC, from the East Coast to the Ohio valley, as demand crept higher. Power use across the region was up 2.2 percent in the hour ended at 4 p.m. versus the same hour yesterday.
Spot on-peak power at PJM’s benchmark Western hub, which includes deliveries to Washington, rose $1.82, or 6.1 percent, to $31.51 a megawatt-hour as of 5 p.m.
--Editors: Richard Stubbe, Richard Stubbe