PJM’s new load forecasting methodology cuts projected peaks for several key benchmarks by 3.5% or more, the RTO said last week.

In response to criticism that its forecasts overestimated loads, PJM has made a number of changes to its methodology. Among them is the treatment of weather, added variables to gauge trends in equipment and appliance saturation and efficiency, and accounting for energy efficiency resources and distributed solar generation. (See “Load Forecast to Include Distributed Solar” in PJM Markets and Reliability Committee Briefs.)

The new methodology has particular ramifications for both the capacity market and transmission planning. It reduces the forecast peak for the 2019/20 Base Residual Auction by 5,660 MW (-3.5%) and that for 2021 — the next Regional Transmission Expansion Plan study year — by 8,406 MW (-5.1%).

The forecast released Wednesday projects a 2016 RTO summer peak of 152,131 MW. That’s a reduction of 5,781 MW (-3.7%) compared with PJM’s forecast a year ago but an increase of 1,836 MW (1.2%) from the 2015 normalized peak.

The RTO’s summer peak is predicted to grow 0.6% annually over the next 10 years, with growth rates for individual zones ranging from -0.1% in the Atlantic Electric zone, which has been hurt by a decline in casino gambling, to 1.2% in the Dominion zone, which is seeing “substantial on‐going growth in data center construction.”

The winter peak load is expected to rise an average of 0.8% per year over the decade, bracketed by Atlantic Electric, which shows no growth, and Dominion, up 1.6%.

The forecast for the APS zone reflects increasing load from natural gas processing plants, which are expected to add 120 MW to 280 MW annually for 2016-2020. The zone’s summer peak is expected to increase 0.8% per year through 2026 with a 1.1% annual increase in winter peaks.

— Suzanne Herel