The Bonneville Power Administration and California ISO said they are working together to boost reliability and manage power flows more efficiently.
The transmission operators March 28 said they expect to soon file with FERC a coordinated transmission agreement that stems from a monthslong effort to better understand each other's operations and how to jointly resolve challenges, the operators said.
"The signing of this agreement not only sets into motion the implementation of system upgrades, but signals the commitment of both parties to continue collaborating and seeking further improvements," BPA Administrator Elliot Mainzer said in a news release.
The issue is tied to operation of CAISO's energy imbalance market. While BPA is not a participant, the federal power agency said the EIM footprint will eventually almost surround BPA's grid. Further, EIM participants in the Northwest rely on BPA's transmission for market operations, BPA said.
EIM participation has grown since its launch in 2014. Current participants in the EIM include PacifiCorp, NV Energy Inc., Puget Sound Energy Inc. and Arizona Public Service Co.
Portland General Electric Co. is set join in October, Idaho Power Co. is expected to join in April 2018, while Seattle City Light along with the Balancing Authority of Northern California and Sacramento Municipal Utility District are slated to join in April 2019.
CAISO President and CEO Steve Berberich said the grid operator and BPA are committed to finding the best outcomes for the customers in getting the most out of the existing transmission system. "This agreement is representative of that commitment and will help BPA potentially defer costly upgrades while at the same time facilitating EIM transfers across their system," he said.
The agreement calls on CAISO to manage EIM flows across BPA's paths within BPA-defined operating limits. The agreement also outlines how CAISO will respond when flows on BPA's transmission system approach or exceed flow limits, following a signal from BPA, the operators said.
The EIM flow-relief tool will require BPA system upgrades that will take a couple of years to complete, they said, noting that CAISO will support BPA through this process.
The agreement also establishes a coordinating committee for further collaboration between BPA and CAISO. A working group of EIM members and BPA transmission customers will also meet regularly to discuss actions being taken under the agreement.