Updated ISO-NE markets ‘primer’ adds section on ancillary services

ISO New England’s Internal Market Monitor (IMM) has issued an updated version of “An Overview of New England’s Wholesale Electricity Markets: A Market Primer.”

Originally published in 2023, the  primer offers plain language explanations of the various markets and products that help keep the region’s electricity flowing reliably. Whether readers are experts or newcomers, the primer is a valuable resource for understanding the electricity industry.

The updated edition, published in May 2025, includes a new section on the recently launched Day-Ahead Ancillary Services Market. Other sections break down in detail the energy markets, the capacity market, and Financial Transmission Rights.

In addition to maintaining the primer, the IMM each year publishes four quarterly reports and an annual report that provide comprehensive performance analyses New England’s wholesale electricity markets. The IMM’s mission includes protecting both consumers and market participants by identifying potential market design flaws and mitigating potential market power abuses.