Switzerland: Swiss blueberry farm extends harvest 4 weeks with 5,220 solar panels elevated 10.5 feet over 4.4 acres

If you’ve ever lost a row of tomatoes to a late frost, you know how personal that feels. You did everything right, the weather didn’t care, and now you’re buying tomatoes at the store like everyone else.

Now say that’s your whole paycheck, and it keeps happening.

That’s been the deal for Olivier Pichonnat, who grows organic blueberries for supermarkets in Lovatens, a village in the French-speaking part of Switzerland. Frost got the flowers on his bushes in 2017. Too much rain came in 2021, followed by hail in 2022. This year brought drought and serious heat. That’s all according to Romande Energie, the Swiss utility he’s now in business with.

So he put a roof over the field. It’s made of 5,220 solar panels, sitting 10.5 feet off the ground above 4.4 acres and 4,500 bushes. That works out to more than one solar panel per bush, which seems like a lot of hardware for something you can buy by the pint.

The word for this is agrivoltaics. It just means growing food and making solar power on the same piece of ground, with the panels up on tall frames and the farm still running underneath.

Romande Energie opened the facility on September 9, with two members of the Vaud cantonal government in attendance. The company describes the project as the largest agrivoltaic installation built in Switzerland to date. I cannot find any larger installation, although that is a relatively low benchmark.

Switzerland doesn’t make this easy

Why a low bar? There’s barely anything to compare it with. A recent report from the Zurich University of Applied Sciences, which pv magazine wrote up in September, puts agrivoltaics at 0.0% of Switzerland’s installed solar capacity once you round it off. The report cites a survey from a couple of years back that turned up just 22 installations.

The law’s a big reason. Swiss planning rules basically say you can’t stick solar panels on farmland just because the sun’s good there. The panels have to help the farming, or they have to be there for farm research.

And it’s slow. One Swiss cherry project took about three years to get from the first chat with the farmer to the first day of construction, going by a slide deck from Insolight, the company that built the Lovatens array.

So you’d have to be pretty fed up to go through all that. Pichonnat seems to have been. “I was starting to have trouble seeing a future without protection for my crops,” he said in the utility’s announcement (that’s my translation from the French).

So why 10.5 feet?

Because of the machines. The utility says the height lets Pichonnat keep using his usual equipment, and its blog says that includes a mechanical harvest.

You’ve probably never seen a blueberry harvester, and that’s fine. The usual kind is basically a tall tunnel on wheels that straddles a row of bushes and shakes the fruit loose as it drives along.

I’d love to tell you how much room that leaves, but neither company has said what he drives or how tall it is. For comparison, a Spanish olive oil bottler we covered is going 13 feet up to clear an 11.5-foot harvester. It’s usually the tallest machine on the farm that decides how high these things go, from the looks of it.

You may also run into different numbers for this array. Swiss public broadcaster RTS reported 5,500 solar panels about 13 feet up, while the utility says 5,220 at 10.5 feet. I’m going with the company paying for them.

So did the roof actually work?

Apparently, yes, although it’s only had one summer to prove it. The Swiss newspaper 24 heures reports that the structure was installed this spring, and it didn’t have to wait long for a test.

The utility’s blog states that growing conditions held up four weeks longer under the panels than they did in the open. It also notes that the bushes outside suffered a decline in health, while those underneath remained in good condition. Furthermore, 24 heures reports that the covered bushes survived the summer without irrigation.

Pichonnat is quoted on Insolight’s website as saying he achieved “a noticeably better harvest.” Frankly, I would prefer to see specific figures, and as far as I can determine, no one has published a single pound figure for this field. Agroscope, the Swiss government’s agricultural research agency, has been tracking several of these projects for years, but I could not find any results from this particular project.

Then there is the temperature. RTS reports that the panels reduce the heat underneath by 9 to 11 degrees Fahrenheit, but it does not specify the baseline for this comparison. This distinction is important, because the same 11-degree figure appears in Insolight’s slide deck as a peak temperature drop compared with plastic growing tunnels, and a plastic tunnel is a very hot environment to begin with.

So why would shade help a plant that needs sun? When leaves get too hot, they basically shut down to save water and stop making food. We saw that play out with Primitivo vines under solar panels in southern Italy, which kept working through afternoons that stopped the vines in full sun. The professor behind that study pointed to a cooler spot in northern Italy where the vines outside the panels out-produced the ones underneath, so don’t assume it travels.

The blueberry data so far is a bit of a mixed bag

The closest hard data I could find comes from Piedmont, in northern Italy. Insolight’s presentation describes a three-year trial there on potted blueberry bushes, with one group under a small 10-kilowatt test rig and another under regular hail nets. It only shows two of those years, and the results are highly variable.

In the first year, the bushes under the panels yielded 27% less than those under nets. In the second, they produced 63% more, a result Insolight attributes to two frost nights and bird damage that affected the netted bushes more severely. Combining both years yields a 1% advantage.

So are solar panels just a very expensive way to break even? I don’t think so. I view it more like insurance. You sacrifice some yield in a favorable year, but you remain operational in a poor one, which is arguably what a farmer who has experienced frost, hail, and heat actually needs.

However, that data should be taken with a grain of salt. It is the vendor’s own data, the presentation does not specify whether the figures are per bush or per another unit, and potted plants in Italy are not equivalent to a 4.4-acre organic field in Switzerland.

It doesn’t work for every crop, either. A German organic oat field we covered last month stayed so wet under its panels that sowing ran four weeks late, and the farming side lost money.

Who pays for 5,220 solar panels?

The utility does, and I’d say that’s probably the cleverest thing about this deal. It paid for the array, it’ll run it and handle the upkeep for 30 years, and it sells the power. 24 heures puts the bill at 3 million Swiss francs, or roughly $3.7 million at September’s exchange rate.

Pichonnat gets the roof and, according to the utility, a second source of income. Neither company has said what he’s paid, and I wouldn’t really expect them to, since it’s a private contract.

The power side’s easier to figure out. The utility expects about 2,400 megawatt-hours a year, and it says that covers about 955 Swiss households.

Your house probably needs a lot more. The average American residential customer buys 10,791 kilowatt-hours a year, according to the Energy Information Administration, so that same output would only cover about 220 American homes against those 955 Swiss ones. Either way, it’s a lot of electricity to get out of a blueberry patch.

Romande Energie’s September 14 write-up says several more seasons will be needed to measure what the panels really do for the crop, and the utility’s on the hook to run them for the next 30 years.

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