State regulators approved an accounting order for Public Service Company of New Mexico’s participation in CAISO’s Extended Day-Ahead Market, in a case that rekindled the debate over which day-ahead market PNM should choose.
The New Mexico Public Regulation Commission voted 3-0 on Oct. 16 to approve the order, which allows PNM to create a regulatory asset for its EDAM costs. That means PNM will track its EDAM costs separately from other expenses and later seek to recover the costs in a rate case.
PNM estimated its EDAM implementation costs will be $11.1 million in capital costs, $3.1 million in one-time operations and maintenance expenses, and $1.4 million to $1.6 million a year in ongoing costs from 2028 to 2030.
The company announced its decision to join EDAM in November 2024 and plans to start participating in fall 2027. (See PNM Picks CAISO’s EDAM and PNM Signs Agreement to Join CAISO’s EDAM.)
PNM’s request for an accounting order sparked filings from those who supported the request and those who believe the company should have chosen SPP’s Markets+ instead of EDAM.
“To me, it’s kind of nuts that this case became a referendum on market choice, or parties tried to make it so,” Commissioner Pat O’Connell said before the vote.
O’Connell said keeping EDAM expenses in a separate account would make it easier to later inspect the costs and compare them to benefits of market participation.
The commission found that it is “reasonable” for PNM to “expend costs in joining EDAM.” The prudency of the expenditures will be evaluated during a future rate case, when the amount of spending is known.
The commission didn’t authorize PNM to include carrying charges in its regulatory asset, saying that doing so would constitute “ratemaking treatment in advance.”
Parties have until Nov. 17 to file a motion for rehearing.
Regional Market Proceeding
In a Sept. 11 filing, Tri-State Generation and Transmission Association asked the commission to deny PNM’s application. Tri-State pointed to PNM’s 2018 request for an accounting order for the costs of joining CAISO’s Western Energy Imbalance Market. In that case, the commission granted the order without making a reasonableness determination.
Commission Chair Gabriel Aguilera said PNM’s new request was unique because it followed a lengthy commission proceeding that examined the potential benefits of regional market participation by the state’s investor-owned utilities. The proceeding included a series of workshops where studies on projected benefits of market participation were presented. Utilities and stakeholders weighed in with numerous filings.
Utilities were not required to obtain commission approval for their day-ahead market participation. But the commission issued a set of guiding principles in November 2024 intended to guide the utilities’ market decisions. (See NM PRC Issues ‘Guiding Principles’ for Electricity Market Participation.)
“PNM’s decision to join EDAM is not a decision that was made quickly or without thorough consideration,” the commission said in its order. Rather, it is a result of “the time, effort and investigation put in by multiple entities that participated in [the docket].”
EDAM Decision Questioned
In its filing, PNM pointed to a Brattle Group study that projected benefits from joining EDAM would be $20 million a year vs. $8 million a year for joining Markets+. PNM said the difference in benefits was a key factor in its decision to choose EDAM.
Tri-State argued that the $20 million and $8 million figures are based on PNM and El Paso Electric participating in the same market. But El Paso Electric has announced its intention to participate in Markets+, while PNM is going with EDAM. (See El Paso Electric to Join SPP’s Markets+ in 2028.)
Tri-State said the benefit difference “is not actually driven by the adjusted production cost but is instead driven by different expectations of congestion revenues and bilateral trading revenue.” A presentation on the findings in August 2024 did not say “with any level of certainty how likely these benefits are to materialize,” Tri-State added.
Tri-State said that key considerations from the commission’s guiding principles — including greenhouse gas tracking, fair governance, seams management and market design — favor PNM’s participation in Markets+ or SPP’s RTO rather than EDAM.
PNM countered by saying its choice of EDAM was a discretionary action.
“PNM’s decision to join the EDAM is not properly before the commission in this proceeding; it is a decision PNM made 10 months ago and informed the commission of at that time,” PNM wrote in a reply to Tri-State.
Western Resource Advocates (WRA) also weighed in on PNM’s accounting order request, saying PNM had acknowledged the commission’s guiding principles for choosing a day-ahead market and presented “a reliable cost-benefit analysis study performed by the Brattle Group.”
WRA recommended the commission approve PNM’s request for an accounting order with the addition of certain reporting requirements before and after it enters EDAM.
The commission’s order directs PNM to provide updates on any “substantive changes to the market” and to file quarterly reports after its EDAM participation begins. The reports will detail cost savings to customers, transmission availability and use, renewable resource curtailment, resource planning impacts and market performance during extreme weather, among other issues.
After two years, PNM must file the reports annually.
