- Phoenix-based Salt River Project (SRP) last week announced it would be joining the Western Energy Imbalance Market (EIM) beginning in April 2020.
- The public utility estimates it can save up to $4.5 million annually by participating in the EIM.
- The agreement with the California ISO makes SRP the ninth market participant. Current members have saved almost $142 million since the wholesale market was launched in November 2014.
The growth of the Western EIM is saving utilities money, while also helping to avoid curtailing renewable energy by automatically finding the lowest-cost energy to serve real-time consumer demands. The market allows utilities to buy and sell power more efficiently in the hour before the energy is needed, with five-minute plant dispatching.
“The EIM produces efficient use of resources and lower costs of energy for participating utilities,” California ISO Steve Berberich said in a statement.
In addition, the market is helping find a home for renewable megawatts that might otherwise have been curtailed. The California ISO curtailed about 80,000 MWh in March, up from 47,000 MWh in March 2016, but a recent report concluded that the EIM helped minimize it.
"If not for energy transfers facilitated by the EIM, some renewable generation located within the ISO would have been curtailed via either economic or exceptional dispatch," the report found. The ISO estimated total avoided renewable curtailments were 6,204 MWh in October, 8,500 MWh in November, and 8,686 MWh in December.
The geographic scope of the market has grown as West Coast and Southwestern utilities have joined: PacifiCorp in Oregon, NV Energy of Las Vegas, Washington's Puget Sound Energy, and another Arizona utility, Arizona Public Service Co.
Other utilities which have agreed to join include: Portland General Electric later this year; Idaho Power next spring, and Seattle City Light and Balancing Area of Northern California/Sacramento Municipal Utility District in 2019. The market serves utility consumers in Arizona, California, Idaho, Nevada, Oregon, Utah, Washington, and Wyoming.