Cal-ISO: APS, PSE began full implementation in western EIM on Oct. 1

Arizona Public Service (APS) and Puget Sound Energy (PSE) on Oct. 1 successfully began full participation in the western Energy Imbalance Market (EIM), the California ISO (Cal-ISO) said on Oct. 3.

The real-time wholesale power market, which the Cal-ISO manages, enables participating utilities to buy low-cost energy available across eight western states, the Cal-ISO said, noting that NV Energy and PacifiCorp are also part of the EIM.

The EIM uses the Cal-ISO’s software to automatically analyze western grid needs and find the lowest cost generation to meet demand every five minutes, the Cal-ISO said. Participating utilities can also access low-cost renewable energy in other western states in real time to offset power generated from local energy plants, the Cal-ISO said.

From January to June, greenhouse gas emissions were reduced by an estimated 292,000 metric tons because of EIM participation, the Cal-ISO said, adding that since launching in November 2014, the EIM has produced benefits of more than $88m, by effectively using the low-cost energy available in the region to meet changes in real-time energy demand.

Participation by APS and PSE “in the EIM will strengthen the market and yield substantial benefits in the form of access to low cost energy for them and for all EIM participants,” Cal-ISO President and CEO Steve Berberich said in the statement.

Future EIM participants include Portland General Electric, which is scheduled to enter the market in October 2017, and Idaho Power, which plans to enter the market in April 2018, the Cal-ISO said.

According to the July 28 Cal-ISO EIM Benefits Report for 2Q16, the estimated gross benefits for April, May and June were $23.6m. Those benefits increased from the last quarter driven by seasonal changes in supply and demand, the report said.

The report noted that the benefits fall into three categories:

  • More efficient dispatch, both inter- and intra-regional, in the Fifteen-Minute Market and Real-Time Dispatch, by automating dispatch every 15 minutes and every five minutes within and across the EIM footprint
  • Reduced renewable energy curtailment, by allowing balancing authority areas to export or reduce imports of renewable generation when they would otherwise need to be economically curtailed
  • Reduced flexibility reserves needed in all balancing authority areas, which saves cost by aggregating the load, wind and solar variability and forecast errors of the combined EIM footprint

The report noted that the EIM began financially binding operation on Nov. 1, 2014, by optimizing resources across the Cal-ISO and PacifiCorp BAAs, which includes portions of California, Oregon, Washington, Utah, Idaho and Wyoming. NV Energy began participating last December, the report said. The EIM facilitates renewable resource integration and increases reliability by sharing information between balancing authorities on electricity delivery conditions across the EIM region, the report said.

About Corina Rivera-Linares 3286 Articles
Corina Rivera-Linares was TransmissionHub’s chief editor until August 2021, as well as part of the team that established TransmissionHub in 2011. Before joining TransmissionHub, Corina covered renewable energy and environmental issues, as well as transmission, generation, regulation, legislation and ISO/RTO matters at SNL Financial from 2005 to 2011. She has also covered such topics as health, politics, and education for weekly newspapers and national magazines.