Still, there’s plenty of space for those panels, even in a future in which most or all of our electricity comes from clean sources, and in which widespread deployment of electric cars and heat pumps ratchets up demand for electricity. Several independent estimates suggest the country could power itself with roughly the acreage currently dedicated to land most everyone would agree is already degraded. And up to 39 percent could be met by putting panels on roofs. “We have tremendous opportunity on rooftops, on parking lots, on other areas like that,” says Garrett Nilsen, the deputy director for the U.S. Department of Energy’s Solar Energy Technologies Office.

Yet rooftops and parking lots are not where most panels are going in Virginia, or elsewhere in the United States. A 2021 study found that most solar panels in Virginia end up in forests and on farmland. And nationwide, about half of new solar is built in deserts; more than four-fifths of the rest goes on farmland, forest land or grasslands, according to a separate analysis.

That makes sense; such land is often cheap and easy to build on. Public and corporate policies are also driving big solar development to such spaces. The 2020 Virginia Clean Economy Act has converged with the needs of one of the state’s fastest-growing industries: data centers. Many of these facilities are operated by tech giants, such as Amazon, Google and Microsoft, that have committed to renewable energy. The centers will soon gobble up two gigawatts of power, a recent report estimated — almost one-sixth of the state’s total power consumption.

Neither the state nor the tech giants determine where new solar projects go. Siting is instead left up to developers, who often seek out large, flat parcels near transmission lines, and to local governments and planning and zoning boards, which are often unprepared to assess solar’s environmental impacts. And Virginia offers relatively few incentives to encourage development on rooftops, parking lots or other developed or degraded areas.

The solar installations that are coming online will help reduce carbon emissions from fossil fuels. But the forests and farms they often replace help the climate too. Virginia’s forests absorb about one-fifth of the state’s emitted carbon dioxide, and it will need every bit of those trees’ carbon-sucking power to offset emissions from hard-to-decarbonize sectors such as transportation and heavy industry, Ms. Dunscomb says.

Forests also support wildlife, prevent erosion and keep pollutants from running off into waterways. Deforested land loses some of its ability to absorb storm water, leading to increased flood risk and dirtier water downstream. At the same time that Virginia is attempting to add some 30,000 acres of forest annually to meet its obligations under the Chesapeake Bay Agreement, which requires that states in the bay’s watershed reduce the pollution they send into the bay, it may be losing close to that amount to new solar arrays, estimates Chris Miller of the Piedmont Environmental Council in Warrenton.