Public Service Company of New Mexico won a victory Wednesday when the state Public Regulation Commission agreed to reconsider who should pay for a 45-mile transmission line that would supply wind energy to the Facebook data center under construction in Los Lunas, among others.

The commission in April denied PNM’s request to charge its ratepayers nearly $40 million to help finance the line, which is planned between Clines Corners and Sandoval County. The regulators initially ruled that Facebook should shoulder the cost of the line.

However, on Wednesday, the commission agreed to let the utility present its case for making its customer base help pay for the power line in PNM’s next rate-increase request. That new rate case is expected to come in 2020, said Commissioner Valerie Espinoza, D-Santa Fe.

“PNM can begin building the power line, but the rate-making element has been postponed to the future,” Espinoza said. “The best thing is for PNM to prove [the need to charge customers] in a rate case. My concern, and I think all the commissioners’ concern, is that ratepayers don’t get stuck with unnecessary charges.”

The estimated cost of the line is just under $44 million. PNM wants to get $39.9 million from retail customers, both business and residential, while about $4 million would be billed to wholesale customers. The PRC hasn’t disputed the charge to wholesale clients.

PNM officials have said that even with the additional cost, retail customers would save an estimated $21.5 million because of the $65.4 million in projected revenue from the Facebook center.

Although a PNM official originally testified that the new power line would only serve the Facebook facility, the company last month filed documents saying a proposed new 140-megawatt wind farm 18 miles east of Estancia also would be linked to the power line.

An affidavit by Thomas Fallgren, PNM’s vice president for generation, said the proposed La Joya Wind Facility, Phase 2, owned by Oregon-based Avangrid Renewables, would serve all retail customers and allow the company to meet its goals for renewable-energy sources in 2021. Avangrid also owns the 166-megawatt La Joya wind farm near Encino, the original planned user of the transmission line.

A spokesman for the utility called Wednesday’s decision “a positive step forward,” saying, “It leaves in place the authority to build the line and allows PNM to present a case for who benefits and covers the costs in a future rate review proceeding.”