By Robert Mullin

California Gov. Jerry Brown on Monday postponed CAISO’s effort to expand into a Western RTO, saying  he wants state agencies to take more time to develop a proposal.

“While very significant progress has been made by the ISO on a transition proposal that meets the criteria in SB 350, there remain some important unresolved questions that would be difficult to answer in the remainder of this legislative session,” Brown said in a letter to legislators.

Passed last year, SB 350 increased California’s renewable portfolio standard to 50% by 2030 while also directing the ISO to explore how its expansion into the wider West could help the state meet that goal.

In response, the ISO commissioned a series of studies investigating the economic, environmental and reliability benefits of regionalization. (See Study Touts Benefits of CAISO Expansion.) CAISO staff also quickly drew up a proposed set of principles for governing an expanded ISO, a task made more urgent by PacifiCorp’s intention to join in 2019. The utility will need to gain approval from regulators in the five Western states in which it operates.

After the original governance plan received a cool reception from many Western industry participants for its “California-centric” nature, the ISO issued a revision to more favorable — if still wary — reviews. (See Revised Western Governance Plan Highlights State Authority.)

Still, some critics were concerned about the rush to complete the proposal in time to seek approval from lawmakers before the current legislative session concludes later this summer. (See Governance Plan Critics Urge Slowdown of Western RTO Development.)

“Regionalization is one of the largest issues facing the ISO in its history,” said Carolyn Kehrein, principal consultant for the Energy Users Forum, which represents large energy customers in California. “Unfortunately, the changes [to the original proposal] were made to meet a quick turnaround.”

Others worried that the revised principles — which eliminated a provision for accounting for greenhouse gas emissions from all generators in an expanded ISO footprint — could compromise the state’s efforts to sharply reduce carbon emissions.

Brown was expected to present the governance plan to lawmakers early this month. The governor said he put off that action in order to allow state agencies to develop a “strong proposal” that the legislature can consider early next year.

“The ISO is pleased with the governor’s and legislature’s continued commitment in establishing a regional electricity grid,” CAISO CEO Steve Berberich said in a statement. He pledged to work with stakeholders “to further refine our governance proposal and any other remaining issues to ensure that all parties have ample time to fully evaluate the impacts of a Western grid.”