California regulators have turned down a $654 million proposal to build 25,100 electric-vehicle charging stations in Pacific Gas & Electric territory, citing the need to hold several hearings before approving such a high-cost initiative.

PG&E filed a proposal for the ratepayer-funded program in February, calling it a key step in realizing Governor Jerry Brown’s plan to have 1.5 million EVs on the road by 2025. The program would have been one of the largest EV infrastructure deployments to date.

“Expanding the use of electric vehicles is essential to California’s success in achieving a reduction in greenhouse gases, and a robust charging infrastructure is necessary to make that happen,” said PG&E spokesperson Greg Snapper, in an emailed statement.

Earlier this month, members of the California Public Utilities Commission decided that the proposal needed further review.

“We must consider the requirement to protect against unfair competition and the demonstrated costs and benefits of any utility electric-vehicle charging station proposal,” Commissioner Carla Peterman wrote in a ruling, the San Jose Mercury News reports. “We find that a more measured approach to utility ownership in PG&E’s service territory is warranted.”

Under PG&E’s plan, a typical residential customer would pay an additional 70 cents per month to cover the costs of the program between 2018 and 2022. Consumer groups expressed concern that this would unfairly increase costs on non-EV customers.

Pasquale Romano, CEO of the EV infrastructure company ChargePoint, told GTM earlier this year that he believes public utilities have an important role to play in the deployment of charging stations. The issue with PG&E’s proposal is that the utility wanted full control of selecting hardware vendors and network services providers, which would reduce flexibility for the site owner and stifle competition among suppliers.

An increasing number of utilities have been exploring the option of installing EV chargers and supporting EV purchases, as a means of growing their businesses. Increased electricity sales from EVs could help the industry remain viable in the long term.

California currently has the largest EV market in the United States. As of mid-2015, PG&E had registered roughly 65,000 EVs, or 20 percent of all EVs in the country. California’s other two investor-owned utilities have also filed proposals to build out EV infrastructure to support the growing number of plug-in cars.

While PG&E won’t be able to move forward with its original plan, regulators have permitted the utility to deploy 2,510 charging stations over the first two years of the project.

“PG&E has a long track record of supporting EVs, and we look forward to working with the Commission to make this happen,” said Snapper.