After a winter of record prices, ISO-NE wholesale market values fell back to more typical levels in March amid milder temperatures and lower natural gas prices.

Energy market value totaled $533 million in March, $7 million higher than the total value in March 2025. Ancillary service market value totaled $9.6 million compared to $7.1 million in March 2025.

The monthly peak totaled 17,861 MW on March 3, marking the highest March peak load experienced since 2019.

“March was relatively boring relative to the winter we just experienced,” said Stephen George, vice president of system and market operations at ISO-NE, at the NEPOOL Participants Committee on April 9. (See 2025/26 Most Expensive Winter in History of ISO-NE Markets.)

He noted that ISO-NE experienced some difficulty accurately forecasting solar production, which can significantly affect daytime demand due to the increasing amounts of behind-the-meter (BTM) solar in the region.

“The rate of growth of PV in the region continues to outpace our ability to forecast it as well as we would like,” he said. Relative to larger regions, the concentration of solar resources in New England makes the region “very prone to small deviations in the weather in terms of cloud cover.”

ISO-NE continues to see between 700 and 1,000 MW of solar nameplate capacity added annually. It currently has about 8.5 GW of BTM solar and about 1 GW of front-of-meter solar.

George said predicting cloud cover and solar output is a complicated and “evolving science.” He added that ISO-NE is communicating with other RTOs and working with vendors to improve the accuracy of its forecasts.

Capacity Auction Reforms Update

Also at the meeting, ISO-NE CEO Vamsi Chadalavada fielded questions from NEPOOL members about key projects, with multiple participants expressing concern about whether the RTO will be able to build adequate support for the second phase of its Capacity Auction Reforms (CAR) project.

FERC recently approved the first phase of the CAR project, which centers around implementing a prompt capacity market and resource deactivation reforms. (See FERC Approves ISO-NE Prompt Capacity Market.)

While the first phase received strong support from stakeholders, the second phase, focused on accreditation reforms and seasonal market changes, likely will be more controversial. Initial impact analysis results presented by ISO-NE in March elicited strong reactions. (See ISO-NE Details Initial Forecast of Capacity Auction Reforms’ Effects.)

Chadalavada emphasized the importance of building consensus and said ISO-NE aims to be open to different approaches while remaining committed to the core design concepts and planned timeline.

“There will be no delay … we have to keep our schedule,” he said. The RTO intends for both phases of the CAR project to take effect for the 2028/29 capacity commitment period, though this will depend on obtaining timely approval from FERC of the second phase.

Changes to GIS Accounts

Lastly, the Participants Committee voted to support changes proposed by Vistra to the NEPOOL Generation Information System (GIS) to allow one GIS login to access multiple GIS accounts. The GIS administrator estimated the changes would cost $186,660.

Some stakeholders expressed concern that the changes would benefit only a small number of participants. The proposal passed despite opposition from the transmission sector and some end users.