December 21, 2023
The Federal Energy Regulatory Commission has approved the Extended Day-Ahead Market, or EDAM, the first wholesale electricity market of its kind in the West – one that may save customers as much as $1.2 billion annually and reduce reliance on polluting fossil fuels.
The EDAM builds upon the Western Energy Imbalance Market (WEIM), a real-time energy imbalance market established by PacifiCorp and the California Independent System Operator (CAISO) in 2014. Since its inception, 22 participants in 10 states and one Canadian province have joined the WEIM, and it has produced more than $4 billion in economic benefits.
In a day-ahead market, participants purchase and sell energy for next-day operations. The coordination of resource supply with forecast demand reduces the number of generators that must be started at the beginning of each day, thereby cutting fuel costs and reducing fossil fuel emissions, while enabling the integration of renewable energy.
In December 2022, PacifiCorp announced plans to join the EDAM. The new market will connect both PacifiCorp and CAISO – the two largest grid operators in the West – potentially unlocking large amounts of clean energy resources with an expanded transmission network. CAISO expects to begin the EDAM in spring 2026.
CAISO serves 30 million customers with a service area that encompasses 132,000 square miles – roughly 80% of California and a small portion of Nevada. PacifiCorp serves 2 million customers across 143,000 square miles in six western states: California, Idaho, Oregon, Utah, Washington, and Wyoming.