Two of the West Coast's largest transmission operators are working together to enhance reliability and manage power flows more efficiently.
For months, BPA and the California Independent System Operator have worked to better understand each other's operations and how they can jointly resolve challenges. The outcome of that collaboration is a coordinated transmission agreement, signed March 1 by BPA's Michelle Cathcart, vice president of Transmission System Operations, and her CAISO counterpart, Eric Schmitt.
Putting the coordinated transmission agreement into use is one element of BPA's overall commercial operations strategy to upgrade systems and processes and enhance broader regional coordination.
"This is a significant milestone in our effort to build a constructive and durable relationship with the CAISO," says BPA Administrator Elliot Mainzer. "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."
At issue for BPA is the operation of CAISO's energy imbalance market, which launched in 2014. The EIM is an automated, real-time energy wholesale market that matches the lowest-cost power supply with demand every 15 minutes and dispatches energy every five minutes. BPA is not participating in the EIM, but the market's growing footprint will eventually nearly encircle BPA's grid, and Northwest EIM participants rely on BPA's transmission for EIM operations.
"From the outset, our top priority was to protect our transmission system and ensure our customers maintain their rights to our system," Cathcart says. "But BPA and CAISO have mutual interests as well. As highly interconnected neighbors, we have to work together to maintain the reliability of the Western Interconnection with timely, effective and efficient actions. We're also able to leverage the capabilities of the EIM to better manage congestion on BPA's end of the grid."
"We are very gratified to see the outcome of the ISO and BPA's collaborative working relationship amongst our teams," said Steve Berberich, CAISO president and CEO. "Both entities 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."
Under the coordinated transmission agreement, CAISO will manage EIM flows across BPA's transmission 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.
"CAISO will use its real-time market in a way that will manage EIM flows in the most accurate, cost-effective way, providing more reliable service for all of our transmission customers," says Cathcart.
The agreement establishes a coordinating committee for further collaboration between BPA and CAISO. And, in response to comments BPA and CAISO received on the draft agreement in late 2016, the pact establishes a working group of EIM members and BPA transmission customers who will meet regularly to discuss actions being taken under the agreement.
CAISO, which is under the jurisdiction of the Federal Energy Regulatory Commission, expects to file the agreement with FERC soon. The EIM flow-relief tool will require BPA system upgrades that will take a couple of years to complete; CAISO will support BPA through this process.