The utility company planning to build a 70-mile power line from northern Baltimore County to southern Frederick County applied Tuesday for a key permit from the Public Service Commission, formally putting its controversial plan in front of Maryland regulators.

Though the Maryland Piedmont Reliability Project remains in its early stages, the proposed line has been a lightning rod for months, dissolving partisan divides and drawing blowback from each county in its path.

In a statement on its application, project developer PSEG Renewable Transmission argued that the line is needed to bolster the region’s power grid amid growing demand. The application lays out a plan that has accounted for community input, impacts to people and wildlife and development costs, project director Jason R. Kalwa said.

“We appreciate the constructive feedback we have received from the Maryland community and look forward to continuing that engagement” during the permitting process, said Kalwa.

The five-member Public Service Commission, which will review PSEG’s application, could approve construction plans, deny them or require adjustments in order to move forward. The review will include a public comment period and hearings.

If constructed, the $424 million Piedmont Reliability Project would be a high-voltage, 500 kilovolt power line running from near the Pennsylvania border — where it would link up with an existing transmission line — to a Frederick County substation, carrying electricity in both directions.

The line is part of a $5 billion portfolio of projects planned by the grid operator for the region, PJM Interconnect, all intended to fortify the region’s electricity delivery system as demands from sources like data centers grow. PJM selected PSEG, a New Jersey-based company, to build the transmission line in a competitive bidding process.

The application to state regulators comes after representatives from PSEG and PJM met with Gov. Wes Moore to discuss the public storm over their project in mid-December.

Prior to the meeting, Moore said he shared “grave concerns” about the project with its opponents, including the developers’ engagement with the community and the process for determining the proposed route.

“The single most important factor remains wholly unclear: the project’s comprehensive benefit to Marylanders,” he said at the time.

In a statement after the December meeting, Moore said he reiterated those concerns to PSEG and PJM and came away confident that they “understand they must be better partners with the state and the community” as they move forward with the application to utility regulators.

PJM has argued that the 70-mile line is needed to accommodate growing demands on the regional power grid, driven largely by the rise of energy-sucking data centers in Northern Virginia, along with other strains like increasing reliance on electrification in cars and buildings.

At the same time, Maryland has seen a steep drop-off in the amount of power it generates within its borders, according to a fact sheet from PJM, in part due to retirements of polluting fuel sources like coal-fired power plants. Without new infrastructure like the Piedmont Reliability Project to bolster the grid, PJM has argued, the region will experience rolling brownouts and blackouts as soon as 2027.

But the project has met a wall of opposition from landowners, environmentalists and politicians from both sides of aisle.

All three counties in the path of the line, Baltimore, Carroll and Frederick, have come out against the project, while hundreds of residents packed into tense informational meetings along the route this fall.

A coalition organizing opponents called Stop MPRP has amassed more than 10,000 members on Facebook and argues that the transmission line would tear up valuable land to power the massive hub of data centers across state lines.

The group is also concerned that developers could resort to eminent domain to cross the land of unwilling property owners — a step that would require permission from the Public Service Commission. PSEG has said it would only rely on eminent domain as a “last resort.”

An analysis by the Chesapeake Bay Foundation found that the transmission line threatens to disrupt hundreds of acres of sensitive terrain along its proposed route. The line would skirt the northern boundary of Gunpowder Falls State Park and in total would impact more than 500 acres of protected land, almost 500 acres of high-quality watershed and some 377 acres of forest cover, according to the analysis.