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Comment by debacle | Hacker News Reader

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 solar arrays. It doesn't make sense.

What would make sense is arrays that are semi-portable that can be used for re-establishing topsoil. With the right crops, good topsoil can be reestablished in as little as 5-10 years.

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I just added this comment below: https://news.ycombinator.com/item?id=35101717

A lot of farming NEEDs sun protection for better yields. Currently farms that don’t have sun protection over compensate by over watering (also could reduce yields).

Not to say every farm should have solar panels but it’s very likely a double digit percentage of farm land would benefit from agrovoltaics.

I'd imagine a significant majority of mass-produced lettuce is grown with some sort of shading to prevent bolting.

Let me introduce you to El Ejido, Spain. A region dominated almost exclusively with greenhouses that block out significant amounts of sunlight

https://en.wikipedia.org/wiki/El_Ejido

https://www.google.com/maps/@36.7520281,-2.7656489,22159m/da...

True, however I think the point is to put more shade tolerant crops under the panels. A lot of the crops we grow are not grown directly for human consumption.

Consider the corn grown for the production of ethanol: why not just harvest the energy directly with solar panels there and grow lettuce or carrots? It would be good to explore other uses for the space as well, like using the panels as shade or cover for livestock.

I mostly agree. As an aside, growing maize for ethanol in the US is only really viable because of subsidies and tariffs. Otherwise, Brazilian ethanol would be cheaper.

Ethanol in the USA is a scam that representatives from states that benefit from the subsidies keep alive.

There are plenty of crops that grow well in or even prefer partially shaded conditions, particularly if there's a significant amount of reflected light as well as there likely would be around a solar array.

> 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).

I think the idea is to use this on the handful of crops that prefer the shade. Think small artisanal alfalfa farms with minimal mechanization.

But all in all I agree that it adds considerable complication for little gain. At least in the US we are in zero danger of installing so many solar panels that there is not enough acres left for food. That kind of concern is orders of magnitude away from reality. Especially if you start displacing corn-for-ethanol acres with solar panels used to charge electric vehicles. In that case you actually increase the available acreage for food crops because the solar panels are so much more efficient than corn ethanol.

Not just alfalfa, but crops where what's eaten is the stems, leaves and other parts of the plant more than the fruits/seeds. Leafy greens, some root vegetables both starchy and wet, asparagus, some brassicas, etc. Not nearly as broad a list as full sun, but I'm also sure there are a lot of things being grown in southern California now that needed a lot of breeding to deal with as much sun as they get there.

Exactly. This idea is so dumb, it reminds me of solar powered roads or solar power on the roof of your car.

There’s no shortage of land out there that can’t be used for agriculture. The American southwest is full of empty land that just happens to be very sunny. There’s no need to comprise the productivity of farms and solar farms alike to try and squeeze them into the same space. Wind turbines on the other hand can work beats they don’t get in the way as much, especially on grazing land.

> There’s no shortage of land out there that can’t be used for agriculture. The American southwest...

Maybe not in the US, but in more populated parts of the world there very much is a shortage of land of any kind.

The article says that having crops under panels might help them through cooling. Options are worth investigating if it makes the whole system more viable.

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