More than 200 northern Baltimore County residents packed into Hereford High School’s auditorium to oppose a $424 million transmission line that would cut through pristine farmland and prized horse country to power both residential growth in Maryland and data center development in Virginia.

The Maryland Piedmont Reliability Project has generated opposition at heated meetings in Frederick, Carroll and Baltimore counties since word of it spread in July. Republican legislators, who only learned of it a few days before the public did, have hastily organized hearings with executives from Public Service Enterprise Group Inc., or PSEG, a New Jersey company that won the contract to build the line from PJM Interconnection LLC.

The legislators criticized PJM, which is the regional transmission organization that coordinates the movement of wholesale electricity through Washington, D.C., and 13 states, including Maryland. PJM hired PSEG in what PSEG executive Jason Kalwa described as a “homeowner-contractor” relationship. Many of the questions about the hiring process and the scope of the project needed to be directed to the homeowner, who was invited but didn’t attend.

“I want to say publicly that PJM’s refusal to engage the citizens of Maryland is wrong, and I find it to be an insult to all of us,” said Del. Nino Mangione, who organized the Baltimore County meeting. “Their behavior and lack of transparency is totally unacceptable.”

Del. Jesse Pippy, a Frederick Republican, said much the same when he organized a similar meeting in Frederick last month.

PJM spokesman Dan Lockwood said he and his team have been answering questions from those who write in, but that developing the route is a task for PSEG and the Maryland Public Service Commission. Maryland imports 40% of its power from other states and has retired or plans to retire 14 coal-fired and natural gas power plants. State laws require 50% of all power to come from renewable sources by 2030, but the state has added few new projects to the grid, Lockwood said.

“PJM has no role in determining the route for this project and only makes determinations about the need for electricity,” Lockwood said. “And the need for electricity infrastructure in Maryland could not be more clear.”

Republican officials from all three affected counties have come out swinging against the project. The Board of Carroll County Commissioners put out a statement saying they “will leverage all its influence with our neighboring jurisdictions as well as state and national leaders to halt the project in its current form.” Mangione said Wednesday he was “totally against” the project and had started an organization, Save Our Community, to lobby against it. Sen. Chris West has distributed a research paper outlining how PSEG could complete the project using existing lines so the company would not have to seize anyone’s property.

Local environmental groups and land trusts have also objected to the project, which would run through hundreds of farms that owners have placed in conservation easements to protect them from development. Two dozen land trusts and conservation groups signed on to a letter calling the project “inherently detrimental” to the properties that land trusts are obligated to protect. PSEG executives have not said how the easements are going to affect its plans, as it will have to wait until officials have completed a full environmental review.

The Democrats’ response to the piedmont project has been more muted, with Baltimore County Executive Johnny Olszewski issuing a statement saying he opposed the company using eminent domain to take property and Frederick County Executive Jessica Fitzwater urging residents to educate themselves about the plans.

PJM quietly hired PSEG in December to build a transmission line that would connect the Doubs substation near Frederick to the Conastone substation in Harford County, near the Pennsylvania border. The company came up with several proposed routes for the line, including ones that run through the area’s drinking water systems at Prettyboy Reservoir and much of its protected farmland that has been in families’ hands for more than a century.

As the contractor, Kalwa said, he couldn’t answer questions about how PJM reached the decision not to use the existing infrastructure for the project, but to his knowledge the amount of power that needed to course through those lines made them insufficient for the task.

Kalwa said PSEG received more than 5,200 comments from the public about the proposed routes, and that the company was reviewing them and taking them into account as they refine the route. Kalwa said the company plans to present a revised route to the public in October or November.

“We are really at the very beginning of this process,” Kalwa said several times at the meeting last night. “The route is not final until we get a permit, which we are very, very far away from.”

The Maryland Public Service Commission regulates utility projects in the state. PSEG has not yet applied for a permit for its project, which is known as a certificate of public conveyance and necessity. The five commissioners vote on whether to approve or deny permits. The governor appoints members to five-year terms with the state Senate’s role of advise and consent. The commission has one vacancy.

Last month’s meeting in Frederick County became so rowdy that organized threatened to call in sheriff’s deputies to keep the peace. The Hereford High School meeting was calmer, but passions still flared.

“This project is destroying what is green and beautiful to us,” Caryn Joachim bellowed into the microphone, to applause. One of the proposed lines would run through her 60-acre farm.

Many worry about the loss of value in their property if PSEG needs their land for its right of way. The company has stressed it rarely uses the eminent domain process to seize land and usually can negotiate an amicable settlement. Kalwa said he regretted the clause on the PSEG project website because the eminent domain issue has become a distraction and frightened residents.

Part of the ire over the project comes from public perception that data centers in Northern Virginia are fueling it, and that their family farms have become a “sacrifice zone” for the nation’s information needs.

Kalwa said it is impossible to say how much of the project’s impetus comes from data center and how much comes from residents’ needs.

Carroll County legislators and commissioners are hosting another meeting from 6 p.m. to 9 p.m. Thursday at the Carroll County Agriculture Center. Doors open at 5 p.m.