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Musings of an Energy Nerd

Equipment Sheds as Solar Mounts

During a recent visit to France, I discovered “hangars photovoltaïques”

During a visit to France, I drove by ten or twelve farms with similar sheds. These buildings were a cross between a photovoltaic shade structure and an agricultural equipment shed. Photo credit: Martin Holladay

A few years after I moved to Vermont in 1974, I was talking with a local dairy farmer in his dooryard, and I said that I admired his new barn. His Vermont answer was classic. “That’s not a barn,” he said. “That’s an equipment shed.”

Oops. Okay. Since then, I’ve remembered the lesson. Cows are sheltered in a barn, while tractors are sheltered in an equipment shed.

While many Vermont dairy farmers are financially struggling, we still have plenty of active farms in Vermont—most of which have at least one barn and at least one equipment shed.

Ground-mounted arrays with tractors underneath

During a recent visit to France, I noticed lots of farms with relatively new equipment sheds. These newer buildings all looked alike. They were steel-framed buildings with steel roofing covered with photovoltaic (PV) modules. Clearly, a local company was promoting this style of building to farmers.

These equipment sheds were a cross between a photovoltaic shade structure—something you might see in a California parking lot—and a farm building.

This French vineyard has a recently completed photovoltaic equipment shed.

Vermont farmers install photovoltaic arrays, too—but in Vermont, the photovoltaic arrays are usually on ground-mounted arrays that make the land unfit for agriculture.

A typical large PV installation in Vermont

The advantage of the French approach is that the photovoltaic arrays didn’t gobble up any agricultural land. When I stopped at a French farm to talk to a farmer about his equipment shed, I asked him how many years it would take for the investment to pay off. “After about 20 years, it’s paid for,” he told me.

What are these buildings called?

Once home in the U.S., I did some Googling to try to figure out what these French equipment sheds are…

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7 Comments

  1. Tim_O | | #1

    I pieced together what it would take to build a mini shed like this. Thinking more 14x20 or something along those lines. Post frame shed, sort of like a "loafing shed." And then use bifacial panels on the roof, no other roofing between. Seal between the panels for water in one way or another. Doesn't need to be perfect, it would be a gravel floor shed. The advantage would be the natural light coming through a bifacial panel. Lots of DIY'ers have done similar things. Not much in the commercial installer space though as you mention. I think a 14x20 post frame shed with gravel floor could be built for $2-3k in material. Depending how large your overhangs are on a 14x20 shed, you could fit about 6kw on the roof.

    1. rlrodgers | | #3

      Probably no US distributors, but Estonian company SolarStone offers roughly what you describe - PV panels acting as roofing (sort of BIPV), 6 kW, etc for a lot less than SunCommon. Simple install with helical screws or the like. https://solarstone.com/products/solar-carport

  2. Expert Member
    MALCOLM TAYLOR | | #2

    Excellent. I was sold on the idea by Kiley's article on Solar carports that Martin linked to: https://www.greenbuildingadvisor.com/article/timber-framed-solar-canopies
    This expands the concept to a scale where it makes even more sense. In urban areas roof top solar is usually the only viable option, but they often sit in an uncomfortable relationship to the roof shape and architecture, and represent a compromise in the number of panels that can be used. Where there is more room, ground mount still ends up using valuable land, with little other benefit. Open or semi-enclosed structures are a natural fit.

  3. AndyCD | | #4

    At 200 kW, an array of this size produces an awful lot of electricity. Many farms are big electric consumers, but certainly not all. They'd have to be grid-tied, of course, and my understanding is that many US utilities don't allow private arrays that generate more juice than the customer uses on site. Would appreciate comment on this matter.

    1. MartinHolladay | | #5

      Andy,
      Of course you're right that U.S. utilities have policies that differ in many ways from the policies in other countries, including France.

      That said, U.S. investors (whether farmers or not) are installing large PV installations in the U.S., and are often finding these investments to be lucrative. (In Vermont, for example, agricultural pastures are being converted into large solar installations at such a fast rate that it's hard for me to keep track of the new "solar farms." Every time I drive to Montpelier, I see new arrays.)

      How lucrative these PV installations are for the investors depends on the details of the electricity purchasing contracts being offered by local utilities (as well, of course, as available incentives from government agencies), which vary widely from state to state.

      1. AndyCD | | #6

        What I'm seeing is a market with two sides: utility-scale and everything else. Here in Ohio we're also seeing massive solar installations; I've been involved in a citizens' group advocating for local permitting. I also know that rules and regs vary widely from state to state. But everywhere, I think, the big players have a whole different set of rules because they're quite literally building or augmenting the transmission infrastructure as well. What I'm curious about is the viability of projects like this--bigger than a typical residential 5 kW rooftop but still several orders of magnitude smaller than utility-scale. These hangars PV approach the size of municipal arrays around me, but those seem always linked to a water or sewer facility that consumes the entire output.

        In another angle, I'm always troubled when large-scale rooftop PV is advanced as a better alternative to utility-scale ground mounts because it doesn't use farmland. Apples and oranges--rooftop has its advantages, but we simply don't have enough roof to do this at the scale needed for our energy appetite.

  4. Expert Member
    DCcontrarian | | #7

    Tax policy is a big part of this.

    In the US, you get a 35% tax credit for a solar installation. The structure that supports your panels is included in that credit, but only if it is necessary to the functioning of the panels. If you build a shed to hold your panels, you can't get a credit for the cost of the shed. However, if you built a standalone frame, you get the credit for the cost of the frame.

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