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Suzhou Sentong
Photovoltaic Co.,Ltd.

Rules for allowing solar farms once again up for debate in N.H.

发布时间:2019-10-12 17:02:29

How do you measure the size of a solar farm?

That simple-sounding question has proven to be quite complicated in Concord, and it will be coming up again soon.

The City Council’s next meeting is expected to include two amendments to a proposed citywide solar ordinance that was tabled in June because some people thought it allowed too few solar panels per property – and that came after it was tweaked because some people thought it would allow too many.

Among the questions that may up come up Oct. 14, are how much total area a given solar farm can cover. Staff are proposing that a 25-acre maximum be increased to 50 acres, which would probably allow a farm that can generate 10 megawatts of electricity. Also up for grabs is the percentage of any parcel that can include solar panels. Solar proponents aim to boost that maximum from 40% to 60% in the residential/open district, which covers much of Concord, with different figures proposed for commercial and community solar as compared to residential, depending on where they’re being proposed.

Those two questions – how big can it be and how much of the property can it cover – crop up for any structural development. The confusing part comes when doing initial measurements.

A solar farm generally consists of rows of solar panels held a few feet above the ground on metal frames set into the ground on cement footings, spaced out so people can walk between the rows for maintenance.

A solar farm is like a building because it is a permanent structure with a foundation and electrical connections. Large solar farms may even have plumbing, to provide water for cleaning the panels. It often requires creating a new road into a previously open field, to provide construction and repair access.

But a solar farm is different than a building because it has no walls and doesn’t completely cover everything the way a roof does. Rain and snow can still get to the ground, reducing the need to deal with runoff that is a major factor in development, and so can sunlight, which means vegetation can grow. Some solar farms are designed to have animals graze between the rows.

The question is how zoning regulations, which have been crafted over decades of dealing either with open space or continuously covered space, should handle this.

Consider an example of a solar farm with 100 solar panels, which is pretty small as farms go.

The average solar panel is a little more than 5 feet by 3 feet in size, about 17½ square feet. Unless they’re lying on a pitched roof, panels are tilted at roughly a 40-degree angle to maximize the amount of sunlight they receive.

So the farm’s panels have a combined surface of 1,750 square feet.

The question is: Should the farm be treated like a 1,750-square-foot building because that’s the total amount of what is called impermeable surface? Concord originally took that approach because it fit under existing zoning regulations.

Or should it instead be treated like a building smaller than 1,750 square feet, because rain and light can get to the ground and the panels are tilted instead of lying flat?

Or should it be treated like a building larger than 1,750 square feet because the rows are spread out, meaning panels and footings must be placed across more of the property?

The latest proposed city ordinance takes the last approach. It measures the perimeter of all the panels in a given array, including the space between them, and makes calculations based on that figure.

This approach was shaped by many complaints from people living near a proposed 54-acre solar farm on West Portsmouth Street, who objected in part to the industrial appearance that it would create. The plan was rejected by the city.

“The reason we do that is for predictability for people who live in this neighborhood, so they can visualize what they could see if it was built,” said Beth Fenstermacher, assistant city planner.

“If we measured by panel (area), then 10 percent could actually cover much of the land” depending on how spread out the rows of panels are, she said. “We think this helps neighbors understand what would be seen.”

Solar power advocates, however, say this approach exaggerates the effect of a solar array, treating open space between panels as if it was covered, and makes it harder to build local solar arrays within city limits. That, in turn, makes it harder for Concord to reach its stated goal of having 100 percent renewable electricity in city by 2030, barely a decade away.

Among those seeking more lenient approaches to measuring the size of solar arrays are Brochu Nurseries, which wanted to put the W. Portsmouth Street array on land it owns, and Clean Energy N.H., an advocacy group.