May 27 (Bloomberg) -- Spot wholesale electricity prices jumped on the power grids in the Northeast as warmer weather sweeping through the region drove consumption higher.
The temperature today in New York was forecast to reach a high of 85 degrees Fahrenheit (29 Celsius), 11 above the historical average, while in Chicago, the high was seen at 78 degrees, 4 more than normal, according to AccuWeather Inc. in State College, Pennsylvania. Analysts typically use 65 degrees as a benchmark for weather that requires no heating or cooling.
Power consumption in Manhattan and its four neighboring boroughs averaged 8,014 megawatts for the hour ending at 4 p.m., which was 1,520 megawatts, or 23 percent, higher than the same time on May 23. On-peak demand in New York City averaged 7,342 megawatts so far today, the highest level since Jan. 7.
The New York Independent System Operator Inc. forecast that hourly average electricity demand in New York City would reach a peak of 8,149 megawatts in the hour beginning at 5 p.m.
Spot power for the New York City market climbed $4.94, or 16 percent, to average $35.30 a megawatt-hour during the hour ended at 4 p.m. from the same time on May 23, grid data compiled by Bloomberg showed.
In the Boston and Northeast Massachusetts market, power gained $20.22, or 47 percent, to average $62.79.
With the price gains, power in the Boston-area market traded at a premium of $9.81 to New York, compared with a three- month average premium of $2.15 a megawatt-hour.