Virginia Debates Impacts Of Solar Panels On Stormwater Runoff

Annapolis MD

29 April, 2022

2:44 PM

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By Whitney Pipkin, the Chesapeake Bay Journal Apr 26, 2022 The new director of Virginia's top environmental agency seemed to be stating the obvious when he said at a conference in late March that "water does not go through" solar panels. But his declaration that solar panels should be regulated as impervious surfaces — followed by a memo from the agency stating the new policy would go into effect immediately — signaled a major pivot in policy. It also sent tremors through the solar industry, which has been rapidly erecting power-generating facilities across the state to meet both the state's and private companies' renewable energy goals. Two weeks later, on April 14, the Virginia Department of Environmental Quality responded to the industry's concerns in a second memo. The agency said it would give projects more time to comply and indicated that stakeholder feedback would be considered in shaping how the policy will be applied. Typical examples of impervious surfaces are roads, parking lots and rooftops. Those types of land cover keep water from soaking into the ground as it would through a natural surface. When rain falls, more of it runs off these hardened surfaces and at higher velocities, causing erosion and washing pollutants into waterways. Polluted stormwater is a major problem for the Chesapeake Bay and its rivers. Regulating solar panels as impervious can be complicated. "The way it was presented was as though it's decided science. I don't think the industry would agree with that," said Harry Godfrey, executive director of Virginia Advanced Energy Economy, a business coalition seeking affordable clean energy. "To treat ground-mounted solar arrays, for runoff purposes, the way you treat a new road or big-box store — the hydrology just doesn't work that way." Many states have chosen to regulate the panels as pervious. They say that the volume and velocity of runoff the panels contribute fall somewhere between farmland and parking lots and greatly depend on the type of groundcover under the panels. Also, agencies have been directed, often by state legislatures, to regulate the solar industry in a more holistic way that takes into account its potential to help wean localities off fossil fuel-based energy sources. As one green-building lawyer put it, referring to Maryland's stance on solar panels, these states are "not trying to alter the laws of science, but rather seeking through public policy to prioritize environmental stewardship." Mike Tidwell, director of the Chesapeake Climate Action Network, said he sees Virginia's change in solar panel regulations as a slight against the state's renewable energy sector. And he said it's particularly problematic for the Northern Virginia epicenter of data centers for companies like Amazon and Google, which have doubled down on their 100% renewable energy commitments. "I think the [Gov. Glenn] Youngkin administration is out of step, and this will have practical economic consequences for the state," he said. Youngkin appeared alongside Google representatives in Reston on April 19 as the company announced plans to invest an additional $300 million in Virginia this year. A Google blog the same week said the company plans to run all of its facilities on "carbon-free energy" by 2030. Amazon also announced plans to power its operations with 100% renewable energy by 2025. Virginia has previously taken a tack similar to other states on solar panels. The Virginia Department of Environmental Quality's previous practice was to consider only the solar panel support posts and beams, which connect to the ground, as impervious areas, the March 29 memo stated. "However," the memo continues, "this approach has the potential to underestimate the post-development runoff volume or runoff rate from solar panel arrays, which in turn has the potential to negatively impact downstream waterways or properties." DEQ Director Mike Rolband had a nearly 40-year career in resource protection before Youngkin appointed him to the post early this year. He expounded on some of the stormwater issues that he thinks have been associated with solar development during remarks at the Environment Virginia Symposium on March 29, the day the memo was issued. "There are all sorts of problems with runoff from solar facilities," he said. "The fundamental issue is that for several years now a decision was made that solar panels are pervious. That's a problem for the downstream folks [because] it doesn't follow the erosion and sediment protocols. It's causing damage to people, and we want to fix that. Solar panel operations in the state have been cited for stormwater violations, but some say those cases do not represent the majority and that using best practices can prevent them. In 2018, heavy rain caused muddy water to gush off the grounds of a newly constructed, 200-acre solar panel project in Essex County and into Muddy Gut Creek, a tributary to the Rappahannock River. A local TV news station ran the headline, "Green solar farm is turning Essex County watershed brown," with a video of murky water flooding part of a roadway and residents who were appalled at the runoff. DEQ later fined the Essex Solar Center and the company behind the project $245,000 for violating stormwater and erosion control laws as part of a consent decree. Even at a well-managed solar facility, there is some debate as to whether the panels have a significant effect on runoff volumes. A 2011 study by the American Society of Civil Engineers found that solar panels did not have a significant effect on runoff volumes as long as certain ground covers and buffer strips are in place. If the ground under the panels is bare or covered with gravel instead of grass, that would increase the need for stormwater management. "The kinetic energy of the flow that drains from the panels was found to be greater than that of the rainfall, which could cause erosion at the base of the panels," the study found. The solar industry has a taskforce researching best practices for reducing stormwater impacts at facilities. As it stands, DEQ's policy change could require solar facilities to acquire 20% more land for projects to offset impervious surfaces, which would have "a significant impact," said David Murray, director of solar policy for American Clean Power. DEQ's first memo states that the state-federal Bay Program also considers solar panels to be impervious areas for the purposes of performing water quality modeling under the Chesapeake cleanup plan. This means, as Rolband put it, that "the rest of Virginia will have to offset" their additional runoff. Bay Program spokeswoman Rachel Felver confirmed that, for modeling purposes, solar panels are considered "impervious, buildings and other" in current land use data. In Virginia, they are reported as "unconnected" impervious to account for the spacing between panels. "However, the impervious land use is not modeling solar panels specifically, and we are still trying to figure out how states are reporting the stormwater management actions and practices associated with solar farms," she wrote in an email. The program's modelers are planning to further discuss those inputs during a technical workgroup meeting in early May. Maryland, Pennsylvania and New Jersey have policies that either consider solar panels as pervious under most conditions or exempt the panels from being considered impervious for the purpose of stormwater management. The Chesapeake Bay Journal is a nonprofit news organization covering environmental issues in the Bay region. Sign up for a free subscription at BayJournal.com.