Hops for beer flourish under solar panels | Hacker News Reader

Hops for beer flourish under solar panels

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Agrivoltaics in general make a lot of sense, especially in mid to lower latitude regions. During peak summer in direct sun the temperatures now are often hotter than is ideal for optimal photosynthesis, and this problem will get worse as the planet continues to warm. Solar panels can soak up those photons on peak summer days -- when there's high AC demand, among other things. (There's also another advantage -- the panels will keep working even in the winter on lands that are fallow in the winter.)

Not to mention with climate change and increased summer temps (like we're suffering now in the northern hemisphere) shading may be required for optimal crop growth.

Also, solar panels can be spread out more to let some light through. That uses more space, but land can be cheap. And that could let other uses like grazing continue making more land available overall.

If the solar panels are tilted to optimize winter production, then during the summer much of the sun will strike the ground between the rows of panels.

PV cells lose efficiency as temperatures increase. Having irrigated crops below should reduce air temp around the cells, slightly improving their power yield.

Yup, this is a mutual benefit -- better PV efficiency and better crop yield.

Wait what??? So 1-2 degrees average is enough to be past peak photosynthesis temperatures? And putting black solar panels is going to bring that back into optimal range? I can’t see any of that being close to factual. Crops under panels could make a lot of sense but not for any of what you said. solar panels raise the localized temp. Solar panels probably keep the area warmer when the sun is down(heat island effect). They also provide shade. Those things could be good or bad for the crop depending on the crop and the region. It’s hot today, I’m going to open the freezer door to cool the house.

At the very least it would be helpful to use a temperature unit when mentioning degrees.

Direct solar light is more than any plant can handle, but the plants are adapted to this, which is why the terrestrial plants are green, instead of being black, in order to reflect a large part of the solar light to avoid overheating, even if this reduces the amount of captured energy.

On the other hand the oceans are dominated by diatoms and brown algae, which absorb a much greater part of the solar light.

There are many plants which are adapted to live in shadows and which would grow well under solar panels, but I do not know if there are many useful crops among them.

> Direct solar light is more than any plant can handle, but the plants are adapted to this, which is why the terrestrial plants are green, instead of being black, in order to reflect a large part of the solar light to avoid overheating, even if this reduces the amount of captured energy.

From what I've read, it's more nuanced/complicated than that. It depends on details of how photosynthesis works rather than just being a simple heat effect. https://www.quantamagazine.org/why-are-plants-green-to-reduc...

It is true that the reasons why phototrophy does not work in a too strong light are much more complex than a heat effect, but also the theory proposed in the paper quoted at your link is too simplistic to be convincing.

The primary pigment use to capture light in all phototrophic living beings which produce elemental oxygen is chlorophyll a, which is blue-green not green.

In the land plants, the blue-green color is masked by the more abundant green chlorophyll b, which is an accessory pigment that transfers the captured energy to chlorophyll a.

So if it is assumed that the color of the pigments has influence upon the regulation of the energy flux (as claimed in that paper) and it is not due to historical accidents, then any such theory must explain why when oxygenic photosynthesis has evolved first in Cyanobacteria, most likely in a terrestrial freshwater environment or in intertidal zones, the optimal color was blue-green, not green as claimed in that paper, then when the Cyanobacteria spread in the oceans in environments with lower light levels (where the luminous flux has even greater fluctuations that require regulation, according to the hypothesis from that paper) the algae have evolved to have accessory pigments that absorb most of the available light, and then, when going back to the continents and exposed to strong light, they have replaced the more efficient accessory pigments with a green pigment, which produces a lower amount of photoelectrons at a given illumination.

The latter fact is easy to understand as just a means to limit the fraction of captured energy versus total energy (in order to not produce more redox agents than can be used by the chemical syntheses that are limited in speed by other factors), but it does not make sense as a means to supposedly diminish the effect of light fluctuations, because these are much smaller in a more intense light flux, with much more photons per second.

Does brown algae(fucoxanthin pigment) really absorb a greater part? Most chlorophyll has a gap in the green spectrum. https://www.mdpi.com/remotesensing/remotesensing-05-06812/ar...

The chlorophylls always have a gap in the green or in the blue-green, where the light is reflected.

However, in the non-green algae there are various accessory pigments, which absorb light in bands not used by chlorophyll and which transfer the generated photoelectrons to chlorophyll, enhancing the amount of the light whose energy is captured.

The ancestors of the green algae, which adapted to a terrestrial freshwater environment, then to the dry land, becoming land plants, have lost most accessory pigments, because they now received more light than they could use.

I think you're right it's more the shade that helps the plants than the reduced temp. But there is a reduction in temp caused by the plants which help the solar panels be more efficient. It's a symbiotic relationship.

It does depend on the crop and how much light the specific plant requires.

If you are sincerely interested you can read about agrivoltaics. There's lots written about it.

On the one hand, crops under solar panels lets the land do double purpose, at least if the alternative as some sort of shade structure.

On the other hand, you've increased the cost of growing the crops, because you need to work around the solar panel structure (which is much beefier than an equivalent shade structure). You've also increased the cost of installing and maintaining the solar panels, because you need to do so at a reasonable height, without damaging the crops, at a relatively low density dictated by the crops.

If land is expensive this makes sense, if land is cheap this doesn't... I wonder how often it's actually worth it.

Hops already need tall poles with ropes in between to grow, so they use existing infrastructure in this case. Plus the machines are already built for it :)

https://thumbs.dreamstime.com/b/ernten-des-hopfens-mit-einem...

Breaking news, some plants are ok in (nevermind prefer) shade?

Hops can be climbers, i.e. inherently companion to some shade-providing plant/tree.

I just learned hops are named exactly for that, jumping on plants and sheep and the town crier or whatever. A Germany / England thing from the very early Crusader Kings timeframe.

English Germanic words are so much shorter and straightforward then all our Romance and tech piffle. :)

interesting theory but a google search for etymology of hop or Hopfen is not conclusive and possible etymological threads do not lead to anything related to "jumping" or to hop / hüpfen.

Reminds me of the "Three sisters" agricultural planting technique.

https://en.m.wikipedia.org/wiki/Three_Sisters_(agriculture)

Curious if there’s any additional maintenance or safeguards needed to keep the hops off the face of the solar panel. Seems like that could be problematic

my first year of hop growth was fantastic, the temperatures were a bit lower during the early summer than they are this year. my second year (this year), the growth is way down and a large percentage of my hops are ready to be picked (about 2 months early).

it will be nice to enjoy fresh hop beer early this year, but I haven't enjoyed the weather that has brought it to us, and not enjoying such a lower yield than last year.

You might look at what AEA has to offer. They have a lot of experience with helping plants perform at peak photosynthesis even if the environmental conditions aren't ideal. www.advancingecoagriculture.com

I can think of some other equally popular but far more profitable plants in Cannabaceae family, I wonder if they enjoy the same conditions.

If you're referring to what I think you're referring to, No.

Those love direct sun and thrive in heat...

There are a bunch of very nice strains adapted for lower light conditions though (growing in the northern latitudes).

Oh for sure and there's Ruderalis (nature to BC/Canada) crosses which will effectively grow to a fixed and uniform height after autoflowering regardless of light cycle.

I expect this trend to grow significantly.

The problem is - nobody cares. The developers in states like NY have a ton of influence at the legislative level and have sweeping powers.

Local governments cannot effectively regulate land use, and solar farm operators just want low overhead, and have zero interest in dealing with farm leases and upkeep.

Err, perhaps you meant to say that nobody in central north america cares.

Countries with far higher per capita uptake of solar panels and battery farms are already well past this, eg:

https://www.abc.net.au/news/rural/2022-05-30/solar-farm-graz...

Eventually non metric backwaters will very likely catch up.

>Eventually non metric backwaters will very likely catch up.

There's a lot of directions I could go with this one, but I won't take the bait. Suffice to say that's not a constructive statement.

The initial proposition that nobody cares was deeply opiniated and clearly flawed.

Highlighting the blinkered vision of fishbowl positions hopefully reduces frequency.

You’re reading it pedanticly. If a landowner controls solar panel placement, sure, they’ll love to plant hops or make it amendable to goat-herding or whatever.

But, they don’t. Solar farms are setup like any other energy entity - they want to extract the most ROI at the lowest possible cost.

Does somebody care? Probably. But not anyone with skin in the game in the United States.

My that looks a lot like a pot calling a kettle names...

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