Closeup of a solar panel covered in raindrops.
Credit: Oregon Department of Transportation / Creative Commons

Virginia solar advocates say an impending stormwater regulation could cost developers millions of dollars and disrupt the state’s recent march toward a renewable energy future.

The rules, floated this summer, are still under review by state environmental officials. They are connected to an order issued this spring essentially requiring solar developers to treat ground-mounted panels the same as parking lots when accounting for stormwater runoff.

Panic about the escalating cost of compliance first rippled through the Virginia solar community in March when the state’s new Republican administration delivered the surprise environmental order in a two-page memo.

Back-of-the-envelope math by solar developers suggested projects would need to acquire roughly 20% more land if the panels — not just the support posts and beams — are also counted as impervious surfaces incapable of absorbing water. If they couldn’t acquire abutting land to accommodate additional drainage infrastructure, they would likely have to shrink the footprint of their arrays.

“That first memo was definitely out of left field,” said Stephanie Johnson, executive director of the Chesapeake Solar & Storage Association (CHESSA), the trade organization representing solar businesses in Virginia and the Chesapeake Bay region. “It was like a sucker punch.”

Two weeks later, the industry was able to breathe a collective sigh of relief when its pushback yielded one concession, albeit small. Michael Rolband, director of the state’s Department of Environmental Quality (DEQ), said in a follow-up April 14 memo that solar projects with interconnection approval secured by the end of 2024 would be exempt from the requirement. All other projects would have to comply.

While that tweak offered temporary consolation, it didn’t end industry jitters. The second memo also stated that DEQ is separately “preparing an agency guidance document to provide additional clarity on the implementation of this memorandum.”

DEQ rolled out its first attempt at that guidance this summer in the form of two documents. In short, both the streamlined plan review and the design plan covered stormwater, erosion and sediment control. It was rebuffed by solar developers, who say its lack of clarity had the potential to place the industry at a standstill.

The design guide addressed solar in a short segment of its 58 pages. Both the overall plan and the design guide are also pertinent for other industries that require DEQ stormwater permits. Ground-mounted solar installations as small as an acre fit into that bucket, as do other construction projects such as housing subdivisions, retail stores and commercial businesses.

For perspective on size, an average acre of land could accommodate enough panels to generate about 100 kilowatts of power, equal to one-tenth of a megawatt. That’s enough to provide electricity for around 10 homes.

Chip Dicks is a former Virginia lawmaker who has served as CHESSA’s legislative counsel for seven years. The memos and subsequent attempts at guidance prompted the solar industry to emphasize to the Youngkin administration how the recent growth of renewable energy is powering the state’s economy, he said.

“We need to supply more certainty to solar development,” Dicks said. “Anything you do in a complex industry like energy has consequences and sometimes these are unintended consequences.”

One of those consequences could be forcing businesses intent on settling in Virginia to look elsewhere for reliable streams of solar.

“There are millions of solar project dollars in the queue,” Dicks said. “Some projects may not be economically viable if developers have to acquire additional land to include more stormwater features.”

The passage of the far-reaching Virginia Clean Economy Act in 2020 has accelerated renewable energy, as intended.

For instance, Virginia has installed upward of 3,845 MW of solar thus far, and more than one-third of that — 1,450 MW — went online in 2021 alone, according to the Solar Energy Industries Association. That total is enough to cover almost 5% of the state’s electricity needs.

Additionally, with 179 solar installers, developers, manufacturers and related companies operating statewide, the industry has invested $4.4 billion in Virginia, figures from the national trade group reveal.

Advocates worry the impervious panel order and DEQ’s pending stormwater guidance will stall progress in a state that ranked fourth nationwide in solar installations last year.

Virginia solar developers were reluctant to speak out publicly on the topic because they fear that offending regulators could jeopardize projects. In background interviews, developers agreed that DEQ should indeed be addressing stormwater protection. They just want to be certain DEQ listens to their input while executing any upgrades.

In late October, Dicks said he fully expected DEQ to follow through on its proposal to release the latest iteration of that guidance in early November. That timeline would have given the agency time to field and review comments, then roll out the final language by the end of the year.

But that wasn’t to be.

“DEQ needed more time to complete their internal reviews,” Dicks said.

It’s unclear when the revised guidance documents will be released. DEQ spokesperson Aaron Proctor would only say that they will be subject to a 30-day comment period once they are released.

NREL studying science of runoff

The North Carolina Clean Energy Technology Center, a clearinghouse for state policy developments related to solar, grid and electric vehicles, hasn’t yet collected data on which states are categorizing solar panels as impervious.

However, the subject has caused enough of a stir nationwide to prompt the Colorado-based National Renewable Energy Lab (NREL) to initiate an on-the-ground study examining the relationship between utility-scale photovoltaic arrays and stormwater runoff.

“We’re just trying to do the science that informs the data that goes into a policy,” said James McCall, an NREL energy and environment analyst leading the research. “We’re not making policy recommendations. This is foundational data for regulators to use.”

The research project is a partnership with the University of Minnesota, Great Plains Institute, and Fresh Energy, which publishes the Vxartnews.

The NREL team is paying close attention to four metrics — soil depth, soil compaction, type of ground cover and spacing of panels — because those are inevitably key considerations for calculating runoff volume and impact of stormwater.

“Every site is going to be different, but runoff from a solar installation is not the same as water runoff on an open field or a parking lot — it’s probably somewhere in between,” McCall said.

The Department of Energy-funded study has published data from monitoring “real-world conditions” at five ground-mounted solar sites in Oregon, Colorado, Minnesota, Georgia and New York ranging in size from 1 MW to 18 MW.

NREL’s online toolkits allow regulators and developers to see actual effects of stormwater runoff and learn about the potential for mitigation. For instance, panel orientation, looser soil and vegetation with deeper roots all have the potential to capture more rain and limit harm to the land and nearby waterways.

While NREL’s three-year study is drawing to a close, McCall expects research on the topic to continue in some fashion because debates about labeling solar panels as impervious will likely continue.

“He’s a policymaker and if he wants to make that policy, that’s his prerogative,” McCall said about Rolband’s decision in Virginia. “Our key takeaway is that we’re trying to inform that discussion.”

DEQ: Following EPA to protect Chesapeake Bay

The timing of the original memo — two months after Rolband was appointed by then newly elected Republican Gov. Glenn Youngkin — puzzled solar advocates because it was delivered without forewarning. Rolband, though, spelled out a pair of reasons for the policy.

One, to be consistent with a federal U.S. Environmental Protection Agency program designed to protect the Chesapeake Bay Watershed that already considers solar panels to be impervious when performing water quality modeling and calculations.

And two, DEQ’s previous practice of counting only panel support posts and beams as impervious has the potential to underestimate the runoff rate and volume, which could harm downstream waterways or properties.

Maryland, a neighboring Chesapeake Bay state, doesn’t count solar panels as impervious, according to a March 2018 memo from that state’s Department of the Environment. That memo also notes that a law Maryland legislators passed in 2012 establishes that impervious surfaces include only the foundation or base supporting the panel.

Rolband, an environmental engineer and former Cornell University professor, is no stranger to broader stormwater runoff concerns in the Chesapeake Bay region. In 1991, he founded a company, Wetland Studies and Solutions Inc., that specialized in stormwater management across Virginia and Maryland. The company helped land developers and public world agencies navigate local environmental regulations as well as the Clean Water Act and the Chesapeake Bay Preservation Act.

Rolband played a significant role in creating Virginia’s new wetlands laws in 2000, and he’s been involved in new stormwater regulations. Upon his retirement last year, the General Assembly passed a joint resolution honoring him for his contributions to sustainable development in Virginia.

Navigating an uncertain future

Despite Rolband’s expertise, solar developers say the transition to the suggested changes would be smoother if decisions hadn’t been made in what they claim is a DEQ vacuum that didn’t take into account distinct nuances of the solar industry.

As it is now, they say their future feels herky-jerky because DEQ didn’t seem to account for the already complicated scheduling of engineering plans, permits, land leases, and power purchase agreements with utilities and other entities.

One developer, speaking on background, explained how counting the panels in a 1,000-acre array as impervious could crush the economics of the project. It would have to double in size if, for instance, it’s determined that the topography requires 200 stormwater catch basins instead of the original 50.

Developers have also complained that DEQ’s memos dictate that the company must assume that panels are in the fullest horizontal position when figuring how much surface area is impervious. That’s not the case, they say, with panels designed to track the sun tilt vertically for much of the day.

However, preliminary guidance in the design guide offers a reprieve of sorts for developers that invest in rain-sensing technology that rotates panels to a vertical position during storms. Depending on the amount of rain, vertical panels wouldn’t count fully toward impervious square footage.

In those cases, the guidance states, only the support posts, columns and beams “should be considered impervious when performing erosion and sediment control, water quantity, and water quality design computations.”

For years, solar developers have lamented the lengthy wait for DEQ to review stormwater plans submitted to the agency. If approvals now take six months to a year, companies worry that the new guidance will only hamstring progress even more.

In the April memo, Rolband acknowledged that the primary issue related to the Virginia Stormwater Management Program is the length of time required to be granted a permit.

The director stated that his agency is “committed to a significant reduction” in those delays but didn’t lay out any specifics. He said only that DEQ will collaborate with stakeholders to create an expedited review process and include it in the guidance documents.

Whatever emerges, CHESSA’s Johnson just wants to be sure it doesn’t compromise Virginia’s position as a clean energy leader.

She emphasized that companies in her trade organization have teams of engineers with decades of experience navigating stormwater concerns in all kinds of terrain.

“We are optimistic the upcoming guidelines will reflect their feedback and expertise,” she concluded.

Elizabeth is a longtime energy and environment reporter who has worked for InsideClimate News, Energy Intelligence and Crain Communications. Her groundbreaking dispatches for InsideClimate News from Kalamazoo, Michigan, “The Dilbit Disaster: Inside the Biggest Oil Spill You Never Heard Of” won a Pulitzer Prize for National Reporting in 2013. Her book, "Outpedaling 'The Big C': My Healing Cycle Across America" is available from Bancroft Press. Based in Washington, D.C., Elizabeth covers the state of Virginia.