CEBA Praises CAISO Board’s Approval of Day-Ahead Energy Market Proposal

Expanded Markets Will Bring Billions in Economic Benefits and More Clean Energy to the Grid

Washington, D.C. (Feb. 1, 2023) — The Clean Energy Buyers Association today welcomed the vote by the California Independent System Operator (CAISO) and Western Energy Imbalance Market (WEIM) boards to approve offering day-ahead energy market services to WEIM participants.

“We are happy the CAISO board recognizes the benefits of expanded energy market services that will benefit all participating states across the West,” said Heidi Ratz, CEBA’s deputy director of market and policy innovation. “Well designed day-ahead market services will help maximize transmission efficiency throughout the region and bring more clean energy onto the grid, all while delivering more than $1 billion in cost savings for energy customers.” 

The CAISO extended day-ahead market (EDAM) would improve market efficiency by integrating renewable resources using day-ahead unit commitment and scheduling across a larger area. The CAISO EDAM process began in October 2019, and the final proposal approved today is the result of many hours of stakeholder engagement to ensure the proposal addresses critical issues including transmission availability and pricing, resource sufficiency needs and criteria, pricing of resources, and market governance. 

In a January 27 letter, CEBA joined a group of stakeholders — including several Western utilities as well as non-governmental advocacy organizations — in urging to the CAISO board and WEIM Governing Body to approve the EDAM final proposal. “The basics on governance, resource sufficiency, transmission access and revenue attribution, and greenhouse gas rules, enable the start of an important new step in regional market evolution,” the letter states.

According to a November study conducted for CAISO by Energy Strategies, a Western day-ahead market could save the region up to $1.2 billion a year from operational and capacity efficiencies while increasing renewable energy output by more than 1,800 gigawatt hours. A 2021 Western state-led study released by the U.S. Department of Energy also found that a full West-wide RTO would increase annual benefits up to $2 billion.

CAISO aims to begin the voluntary day-ahead market as early as 2024. Approval of the EDAM proposal authorizes CAISO staff to draft and submit tariff changes to the Federal Energy Regulatory Commission (FERC) for approval before market services can commence.

The CAISO EDAM final proposal offers one Western market option, and Southwest Power Pool (SPP) also has begun work on its Markets+ proposal for a Western day-ahead market and related services. The SPP Markets+ proposal also is anticipated to bring economic benefits; a 2020 Brattle Group study found that a SPP Western RTO would create benefits of $25 million per year for Western Energy Imbalance Service members and $24.2 million annually for SPP members.


The Clean Energy Buyers Association is a business trade association that activates a community of energy customers and partners to deploy market and policy solutions for a carbon-free energy system. CEBA’s more than 350 members represent more than $7 trillion in annual revenues and 14 million employees and include institutional energy customers of every type and size – corporate and industrial companies, universities, and cities. For more information, visit and follow us on Twitter and LinkedIn.