The California ISO on Jan. 30 said that its western Energy Imbalance Market (EIM) 4Q17 benefits report shows that the real-time EIM produced $33.46m benefits for its six participating members.
The benefits since the western regional market was launched in 2014 now total $288.44m, the ISO said.
The EIM’s technology automatically finds and delivers low-cost energy to serve consumers in California, Arizona, Oregon, Washington, Utah, Idaho, Wyoming, and Nevada, the ISO said, noting that in addition to leveraging the diverse resources from a larger pool, the effective use of carbon-free generation provides added environmental benefits.
According to the ISO, Western EIM participants helped reduce carbon emissions in the region by 7,730 metric tons by using 18,060 MWh of excess renewable energy that otherwise would have been turned off.
The ISO said that besides using low-cost energy, EIM utilities reduce their costs by being able to join together to decrease the amount of energy reserves that individual utilities must carry in real time to manage load.
During 4Q17, PacifiCorp realized benefits of $6.83m, while the ISO saved $4.52m and Arizona Public Service $10m, the ISO said, adding that NV Energy saved $6.45m, and Puget Sound Energy saved $2.83m during the three-month period.
The EIM’s newest participant, Portland General Electric, saw $2.83m in benefits, the ISO said.
Idaho Power and Canada’s Powerex are on track to join the market on April 1, while the Balancing Authority of Northern California/Sacramento Municipal Utility District and Los Angeles Department of Water and Power will begin participating in April 2019, the ISO said. Salt River Project and Seattle City Light are set to enter the market in April 2020, the ISO said.
According to the report, a significant contributor to EIM benefits is transfers across balancing areas, providing access to lower cost supply, while factoring in the cost of compliance with greenhouse gas emissions regulations when energy is transferred into the ISO. As such, the transfer volumes are a good indicator of a portion of the benefits attributed to the EIM, the report said, adding that transfers can take place in the fifteen-minute market and real-time dispatch (RTD).
Generally, the report said, transfer limits are based on transmission and interchange rights that participating balancing authority areas make available to the EIM, with the exception of the PacifiCorp West (PACW)-ISO transfer and Portland General Electric-ISO transfer limit in RTD. Those RTD transfer capacities between PACW/PGE and the ISO are determined based on the allocated dynamic transfer capability driven by system operating conditions, the report said.
Among other things, the report said that the EIM benefit calculation includes the economic benefits that can be attributed to avoided renewable curtailment within the ISO. 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 said.
“The total avoided renewable curtailment volume in MWh for [4Q17] was calculated to be 9,444 MWh (October) + 5,974 MWh (November) + 2,642 MWh (December) = 18,060 MWh total,” the report said.
Under the assumption that avoided renewable curtailments displace production from other resources at a default emission rate of 0.428 metric tons CO2/MWh, avoided curtailments displaced an estimated 7,730 metric tons of CO2 for 4Q17, the report said.