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Dulles solar farm would be the nation’s largest at an airport

It would be among a growing number of airports to install solar arrays on otherwise undeveloped land

A rendering of the solar farm that is being proposed at Dulles International Airport near Washington. (Dominion Energy Virginia)

Dulles International Airport could soon be home to the largest airport-based solar and battery development in the United States, one that at peak production could provide enough energy to power more than 37,000 Northern Virginia homes.

The solar farm would be built and managed by Dominion Energy on more than 835 acres on land. It would include a solar array capable of producing 100 megawatts of solar generation and a 50-megawatt battery storage system. The power generated would feed the larger Northern Virginia electrical grid.

Once built, Dulles would join a growing number of airports across the country looking to solar developments as a way to meet sustainability goals, save money on electricity and generate revenue from land that might otherwise be undeveloped. The project is one of dozens the Virginia utility company is building as it shifts to meet the mandates of a sweeping clean-energy law that state lawmakers passed in 2020.

“It is land adjacent to a runway that has not great building potential,” said Thomas Beatty, vice president of the engineering office at the Metropolitan Washington Airports Authority. “No one wants to build a hotel next to a runway, so for us and them it made good sense.”

The Dulles project is a response to the Virginia Clean Economy Act, which requires Dominion to deliver electricity from 100 percent renewable sources by 2045, while Appalachian Power of Southern Virginia must be carbon-free by 2050. The measure also set a timeline for closing old fossil-fuel plants and mandated gains in energy efficiency.

In addition to the proposed solar and storage work at Dulles, Dominion is also building the largest offshore wind project in the United States off the coast of Virginia Beach and a project in Southern Virginia, known as Highland Solar, that will convert a coal mine into a solar farm.

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Under the proposed Dulles deal, Dominion would lease land from the airports authority, which manages Dulles and Reagan National airports. The Metropolitan Washington Airports Authority would not receive traditional rent payments, but instead, Dominion would build two 1-megawatt solar carports to provide power for the airport and give the authority 18 electric buses and 50 electric vehicles.

Dominion also would provide the airports authority with charging infrastructure for the vehicles. Dominion spokesman Aaron Ruby said the agreement could be a model for airports across the country considering similar ventures because it incorporates both renewable energy and clean transportation.

The project is awaiting final federal approvals from the Transportation Department, which Ruby said could come later this year. Construction could begin in 2023, and the development could start generating power in the second half of 2024.

Transportation Department officials did not respond to a request for comment about the project. In February, the Federal Aviation Administration determined the project would not interfere with the airport’s aviation operations.

“The FAA supports these projects as long as they do not affect the safety and efficiency of the airport and the airport’s ability to satisfy existing and future aviation demand,” the agency said in a statement. “The solar project at Washington Dulles International Airport meets these criteria.”

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A preliminary environmental assessment of the project’s possible effects was done last year, looking at possible sites for the solar development. In a letter to the Metropolitan Washington Airports Authority in response to that assessment, groups including the Piedmont Environmental Council, the Loudoun Wildlife Conservancy and Northern Virginia Conservation Trust urged Dominion and the authority to install solar panels on existing buildings and above parking areas to reduce the effects on undeveloped land.

Ruby said Dominion evaluated several alternatives as part of the study, including rooftop installations. He said the assessment concluded that building on structures was not a feasible alternative because of limited rooftop space available for solar installation. The company also determined the ground-mounted solar array would be more cost-efficient for customers and produce more energy than rooftop panels.

The plans call for the solar farm to be constructed in the southwest corner of the airport near Loudoun County Parkway. A final environmental assessment is expected to be sent by the Metropolitan Washington Airports Authority to the FAA for review later this year. The FAA said it is working with the authority on completing the federal environmental review of the project and awaits its final submission. Dulles, located about 25 miles west of Washington, is among several airports nationwide seeking to harness the sun’s power in recent years.

A 2020 study by Serena Kim, a research associate in the College of Engineering, Design and Computing at the University of Colorado at Denver, found that 20 percent of the 488 public airports in the country are using solar energy. Kim said she expects that number will grow. “Airports will continue to deploy solar projects because solar panels and batteries are getting cheaper, and airports can diversify the energy mix and promote energy security,” Kim said.

In most instances, airports contract with a company that builds and manages the solar development, although financial arrangements vary. Indianapolis International Airport will generate over $9 million from land it leases to a private company for a 183-acre solar farm, the first phase of which began operating in 2013. The development’s more than 87,000 solar panels produce enough energy to power 3,675 homes. Kent Ebbing, project manager for property development at Indianapolis International Airport, said solar power is a resource all airports should consider.

Denver International Airport, which in 2008 became one of the first to install a solar array on its campus, purchases some of its electric power at a discounted rate. That arrangement has saved the airport millions of dollars in energy costs, said Scott Morrissey, senior vice president of sustainability at the airport. “We are going to power our growth with electricity that is low carbon, cost-effective, reliable and resilient,” he said. “Solar really has to be a part of that.”

Pavel Molchanov, an energy analyst with financial services firm Raymond James, said Dominion’s investment at Dulles comes as a growing number of companies are shifting to renewable energy as part of their environmental, social and governance goals.

Molchanov said solar has become the fastest-growing power source in the world, in part because it can work in a variety of settings and in large areas of land that might otherwise be unbuildable. He said it can make an airport with a large geographic footprint like Dulles, which sits on more than 12,000 acres, an ideal site. “There is a lot of space,” he said. “Think of all that grassy territory around runways that just sits there empty.”

Even airports with limited acreage can take advantage by installing solar panels on top of terminal buildings, Molchanov said. Wind is a popular alternative in some settings, he said, but is not viable around airports because of the effect turbines can have on flight operations. After years of looking at different proposals to create solar energy at Dulles, airports authority and Dominion officials said they are eager to move forward with the project.

“A clean-energy transition is happening. Every passenger that takes off and lands at Dulles is going to see this array,” Ruby said. “So that is kind of cool that all of the passengers that are traveling in and out of Dulles are going to see that same energy transition unfolding.”