As any builder knows, one of the biggest pains in the neck when putting a large object on a piece of open land is figuring out what it will do to water that falls from the sky.
When rain hits a newly built surface that keeps it from soaking into the ground, it moves as runoff. And it might move to the wrong place — such as your litigious neighbor’s front yard — unless you work hard to divert it.
That is why developers need the state to give them “alteration of terrain” permits for big construction projects. In theory, these show that you’ve done the work needed to keep changes in runoff from causing problems for those around you. But for the brand new Brochu solar farm in Concord and many other large ground-mounted solar arrays in New Hampshire, the permits can be a problem themselves if they treat solar arrays too much like traditional buildings.
“New Hampshire had not seen a whole lot of solar projects” when the project was approved in 2024, said Oliver Sandreuter, senior director of business development for Lodestar Energy, which built the array on land owned by the Brochu family of nursery fame. “If a state is new to the solar development landscape … it can be hard to know what to do.”
Solar panels are “impermeable surfaces” in engineering lingo: Rain bounces off them. And the 5 megawatt AC Brochu farm has about 11,000 panels standing above the ground on frames, which is a lot of impermeable surface.
Those numbers led to a calculation of likely runoff that required construction of two infiltration basins to hold all that collected water, as well as a swale — a small earthen wall — to keep it from flowing off the property.
But the solar panels are tilted, facing south for maximum energy production, and the rain that bounces off them lands on dirt or grass, not pavement.
Sandreuter said Lodestar’s experience with building, operating and owning solar farms throughout New England indicates that the arrays will make almost no difference from runoff that already happened on the open field. The basins, he predicted, will never fill up.
Among other things, this is an example of technology outpacing regulations. Twenty years ago, before solar was cheap, nobody thought folks would pay to build long rows of tilted metal sheets on their land, so regulations didn’t take that into account.
At least the Brochu project, located on flat land with an owner who has been trying to build solar for a decade, made business sense. It will have an official ribbon-cutting on Friday.
“There were other projects that we had to abandon because the stormwater requirements would have been too punitive,” Sandreuter said.
Incidentally, if you’re worried about solar taking over farmland, Brochu Nursery has tried and failed for years (Len Brochu Sr. bought the parcel in the 1970s) to grow anything on this roughly 15 acres in a bend of the Merrimack River, which once held a pine grove that was killed by disease. And note that this is far from the Brochu Nursery plot next to I-93, which has held a much smaller solar array for more than a decade.
Since 2024, the state’s regulations on alteration of terrain calculations for solar arrays have eased a bit, but New Hampshire is still tougher than other New England states that Lodestar has dealt with, Sandreuter said. “Our position is still that stormwater calculations are difficult in New Hampshire. It’s good to see minor improvements … but more is needed.”
Sam Evans-Brown, director of Clean Energy New Hampshire, agrees. The state Department of Environmental Services “did a good job of tweaking rules, making it more realistic, less conservative and, to be a little glib, less insane,” he said. “We’re lucky that was even go-ahead for this; there’s like a million ways that solar projects can die. … This was a perfect site — an unproductive site, flat, close to a substation — and still it’s hard to get these things done.”
“It’s hard to build solar in New Hampshire, too hard,” he said.
If you’ll pardon a minor rant, I’m baffled why that is.
We’re supposed to love local control and you can’t get more local-control-ish than making your own electricity instead of buying it from a far-off company. You would think there would have been years of Granite State support for putting panels on every building and parcel of scrubland, but lawmakers, especially Republicans, have dragged their feet despite their supposed love of do-it-yourself libertarian philosophies.
For example, this array isn’t bigger than 5 MW only because that’s as big it can be and still get paid for its electricity under state law.
Perhaps the latest election will change that. Let’s hope so: We’re living in a turbulent world, so the more we can control our own destiny, the better.
