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Growing crops under solar panels

fastcompany.com

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Re: Growing crops under solar panels

#41

Post by outworlder »

debacle wrote: post #6

This idea is being pushed hard right now. I see it everywhere. You can't grow most crops under solar panels. And the crops you can grow will probably have a lower yield. This is an idea that's meant to push replacing farmland with solar arrays. I don't necessarily think that's a bad idea for low yield soils, but in my area they are trying to replace high-yield soils (former orchards, vineyards, market gardens) with s…

> You can't grow most crops under solar panels

What sort of crops and how long are the panels blocking sunlight for?

For some crops there is such a thing as too much sunlight (or too much heat).

Re: Growing crops under solar panels

#44

Post by schiffern »

defrost wrote: post #33
throwuwu wrote: post #3

I’m no farmer but wouldn’t putting a whole bunch of stuff in a field make it difficult to drive a tractor through it? Like have you seen the size of modern tractors? These panels will need to be 20ft in the air with support posts really far apart to accommodate seed drills and sprayers and other equipment that the tractor pulls behind it.

Picture of sheep grazing under panels in Australia: Solar farm trial shows improved fleece on merino sheep grazed under panels https://www.abc.net.au/news/rural/2022-05-30/solar-farm-graz... Note the room to drive between panel rows and for "boom mowers" to spread out behind a medium tractor and reach under the panels. There are also many types of vehicles used in agriculture from two storey high broad acre heavy dut…

>improved fleece on merino sheep grazed under panels

Makes sense. I'm not sure the exact care instructions, but I'm pretty sure "store this garment outside unshielded in the baking sun and pouring rain for many months" isn't the official recommendation for wool.

If available, sheep (and other animals) will seek cover during heavy rains and periods of high heat stress. This protects both the sheep and the wool, and both factors improve quality.

I wouldn't be surprised if the diet improves as well, due to healthier grass, higher plant biodiversity, and higher abundance of (tasty and nutritious) insects.

Paradoxically, primary productivity will often increase with added shade, because photosynthesis shuts down at even mildly elevated leaf temperatures (~85 °F). Those vast impressive corn fields will often overheat and shut down around 10 AM, and don't start photosynthesizing again until 4 PM.

In ye olden days farmers would plant a widely-spaced grid of "farmer's trees."[0] These are a category of trees (eg black locust) which 1) provided shade and windbreak, 2) coexist with crops right up to their trunk, 3) have deep tap roots bringing up minerals and water, 4) drops fertilizing mulch, and 5) produces nutritious animal fodder (pods) which self-dry and store on the tree itself. Clever farmers!

For mechanized farms you can choose a planting pattern and varieties that permit machinery to drive right past the tree without losing much area on "gores." Typical density was about 20-30 trees per hectare, so it also stores a bit of carbon.

Personally I prefer trees, but ultimately we need both types of systems.

[0] https://www.youtube.com/watch?t=25&v=uvQpIHBSPBE

Re: Growing crops under solar panels

#45

Post by lovemenot »

mminer237 wrote: post #31
detourdog wrote: post #28

Earlier quoted context omitted.

I can tell you are no farmer. No tractor is needed in a field maintained by grazing. If tbe panels are mounted high enough sunlight will be cast on the ground for a period each day.

I am a farmer, and this doesn't make sense. Grazing fields aren't really growing crops. Even if this is just crops that are picked by hand (it mentions broccoli), they typically still have huge machines follow the laborers for them to deposit them in: https://www.youtube.com/watch?v=bKyxMKO2kyU I can't see any good way to harvest a field with solar panels that isn't so inefficiently laid out that it would be better t…

I am not a farmer, but am interested in watching the development of agricultural tech.

>> I can't see any good way to harvest a field with solar panels that isn't so inefficiently laid out that it would be better to have two separate fields.

Would there be scope for smaller autonomous machines? Presumably, there should be some crop configurations that could benefit, but we don't yet have all the results of experiments currently running. Here in Japan, farms are typically much smaller, so there's perhaps greater scope for agrivoltaics than in industrial scale farms in USA.

Re: Growing crops under solar panels

#47

Post by downrightmike »

thethethethe wrote: post #21
crooked-v wrote: post #17

I really don't get why people keep coming up with all these elaborate plans to mix solar panels with other stuff that's in active use, instead of just putting fields of them out in non-endangered desert elevated enough off the ground that they won't actively interfere with local animals.

Why would we destroy pristine desert, which is rapidly disappearing, when we could cover land that has already been disturbed, like parking lots, building roofs, and farmland? Deserts are important ecosystems regardless of their immediate utility to industrial society

It plain makes more sense to generate the power as close to use as possible

Re: Growing crops under solar panels

#48

Post by lovemenot »

ed25519FUUU wrote: post #37

This is a very CA-centric research topic. In most of the US heartland theres millions and millions and millions of acres of farmland. There’s no need and limited benefit to mixing PV with agriculture. And the places where it does make sense it makes sense only for running goats around in the PV sites to keep weeds down.

That's a very USA-centric comment. To the best of my knowledge, the two countries doing most research on agrivoltaics are Japan and China.

Re: Growing crops under solar panels

#49

Post by photochemsyn »

throwuwu wrote: post #3

I’m no farmer but wouldn’t putting a whole bunch of stuff in a field make it difficult to drive a tractor through it? Like have you seen the size of modern tractors? These panels will need to be 20ft in the air with support posts really far apart to accommodate seed drills and sprayers and other equipment that the tractor pulls behind it.

Vertical bifacial panels are one approach that doesn't interfere with tractors and equipment, and still have comparable generation (with twice as many panels, so more expensive):

https://www.pv-magazine.com/2023/01/24/vertical-pv-for-clean...

> "For conventional ground-mounted systems, the scientists considered a tilt angle of 20 degrees and an average estimated energy yield 1,020 Wh/W. For the bifacial vertical west-east oriented systems, they assumed a bifaciality factor of 90% and an annual energy yield of 999 Wh/W, while for vertical systems with a north-south orientation the annual energy yield was indicated at 926 Wh/W."

Re: Growing crops under solar panels

#50

Post by dzhiurgis »

orbital-decay wrote: post #35
f0ld wrote: post #34

They’re talking about transparent solar panels right? HN has been very weird lately. Was this article topic suggested by chatGPT?

No, it's for the areas with excessive insolation - the idea is to use solar panels to create some shadow, reducing the exposure to sunlight for crops and wildlife, which benefits both.

Which means bifacial panels would suit even better
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