IID is preparing to join the Western Energy Imbalance Market and the Extended Day-Ahead Market, two major regional energy markets operated by the California Independent System Operator (CAISO).

These markets are intended to enhance the efficiency of energy trading across the Western interconnection. By participating, utilities like IID can lower operational costs and strengthen system reliability. Importantly, these market structures allow IID to retain full control over its Balancing Authority functions, including decisions about generator interconnections and the development of transmission lines.

What Is the EIM?

The Energy Imbalance Market is a real-time energy market that allows participating balancing authorities to buy and sell electricity every five and fifteen minutes. Launched in 2014, EIM has helped reduce costs, enhance reliability, and improve regional coordination for its participants.

What Is the EDAM?

CAISO is set to launch the Extended Day-Ahead Market in 2026. It builds on the EIM by allowing utilities to plan energy purchases and sales one day in advance. Since most energy is scheduled ahead of time, EDAM is expected to deliver even greater savings and efficiencies for participating utilities.

Why IID Is Participating

IID began evaluating market participation in 2022. After conducting an economic assessment and a comprehensive gap analysis, both of which were reviewed by the IID Board of Directors and the Energy Consumers Advisory Committee in early 2023, it was determined that joining both EIM and EDAM would bring:

• Improved access to energy resources
• Greater transparency in the energy market
• More efficient scheduling

As neighboring utilities have already joined these markets, IID’s current energy procurement options have become more limited. This has led to reduced resource availability and increased costs. Participating in EIM and EDAM will help IID maintain reliability and competitiveness for the long term.

What’s Next: Phase 3 Implementation

IID is now moving into Phase 3, which focuses on implementation. This includes major system upgrades and operational changes such as:

• Control infrastructure and system integrations
• Upgrades to telecommunications, metering, and generation plant systems
• New scheduling and settlement platforms
• CAISO participation agreements
• Hiring additional staff, staff training, and development of new operational procedures

IID plans to enter both markets at the same time, becoming the first utility to do so. This approach is supported by CAISO as both efficient and beneficial. IID is targeting a market entry in 2028, with the final date to be determined through an implementation agreement with CAISO.

Financial Impact

Phase 3 implementation of the Energy Imbalance Market project is expected to cost an $24.2 million, bringing the total estimated project cost for Phases 1, 2, and 3 to $31.8 million.

Visit the Western Energy Markets EIM website to learn more.