Specialty cut flower grower here. Backyard scale, but we're profitable and have received some grants so that means we have had a USDA relationship for a couple years. The rep I've talked to and am closest with is skeptical of agrivoltaics due to past dealings with solar companies (not sure what she means). There doesn't seem to be enough reliable public data to make it seem like the win-win-win we want it to be. In their mind, you're adding a non-ag industry to the land and that could have downstream consequences in a generation. Maybe you're scheming to get the land re-zoned for light industrial; I honestly have no idea what they're thinking, but they're averse toward it.

Most flowers in 7b don't want extreme sun. We use shade cloth frequently, so solar coverage would be fine and of course have the energy co-production. Cut flowers aren't harvested mechanically at our scale, so we wouldn't have to worry about tractor access.

Meanwhile, more and more food is produced under cover for a lot of good reasons. Polytunnels, glass houses. You might get some summer shade from solar but what about season extension at the beginning of spring/end of fall? Depending on your crop and location, that could mean 4-8 extra weeks a year. What if you do geothermal energy generation for the tunnel? Now you can grow through the winter and not need the same footprint as solar. That's more appealing to me.

Anyway, I'm forever mad at corn ethanol and we should at least replace all that with solar farms. That's probably the right place to start. But also, again, zoning...

Completely off topic but I'm fascinated with this. How much acreage do you devote to this?

I've done hobbyist exotic (legal!) mushroom farming for a while, at a scale that is more than I could use but not like 100x what I could use. I've thought about selling but it seems like a lot of hassle doing the marketing and business parts of it.

How do you sell? Do you have a distributor that purchases product from you or is it a farmers market type deal?

Flowers sell themselves. I help with labor and fertilizer and planning, but my wife plans the grow out and designs and delivers. Local delivery, subscriptions, partner with restaurants and others in the event space. We sell online within a delivery area as well.

You sound like a neighbor of mine - have any recent issues with the county septic system requirements

> forever mad at corn ethanol and we should at least replace all that with solar farms.

Thats around 50k sq miles, which would generate ~5x more electricity than the US uses

TIL: 7b refers to USDA Plant Hardiness Zone 7b, a climate classification used in the US to indicate the average annual extreme minimum winter temperature.

Zone 7b: −15 to −12.2 °C

Zone 7a: −17.8 to −15 °C

Zone 8a: −12.2 to −9.4 °C

FYI the measurements used by the USDA are Fahrenheit, a zone is +/- 10F. There are zone 1-13 though not all exist in the US. If I recall correctly about a decade or two ago we began subdividing them into A and B zones. Where before you had zone 6 for 0 to -10 (my local zone) but now you have 6a (-10 to -5) and 6b (-5 to 0).

Its also not just the average minimum temp, its the average minimum temp over the last thirty years. A few years ago my zone changed from 6a to 6b following the regular reevaluations the USDA does.

Edit: the A/B zones were developed in 1990

Would also love to hear more about your project!

Regarding that person that's critical of photovoltaics in ag, I guess their point is similar to someone telling you "stop adding Google ads to your blog, otherwise at some point you will be their slave"

It might be the same for ag, at some point energy companies are going to tell you how much you need to rent their panels / what you're allowed to cultivate / your revenue is going to depend so much on them rather than the culture that you'll effectively become just a field with solar panels and no culture

Perhaps if ag people used some kind of "cooperative structure" they can fight this

Very conservatively solar produces 30-50 times are much energy per acre as corn ethanol. I think if you consider just the ethanol to mix with gas vs charging an electric car with solar it's a 100 times more.

Something around 2500W of solar can provide enough energy to drive an EV 12,000 miles a year.

When it comes to zoning. The state should require offices to install chargers for employees cars when the solar share of electricity generation is highest.

I agree, but I always wonder: where do you store the energy from solar? Ethanol just goes into a boring tank. Electricity is expensive to store, especially at the scale we're talking. Carrying via cable all the way from the farms to the industrial centers is expensive aswell.

"[lithium ion battery prices] declined by more than 99%. In 1991, lithium-ion batteries cost around $9,200 per kilowatt-hour — 33 years later, they cost just $78."

https://ourworldindata.org/battery-price-decline

The price of battery storage is dropping exponentially, just as the price of solar power has. Eventually, the price becomes pretty trivial.

The scale we're talking here is not just a shack with a couple of batteries. Even with low prices of today, we're talking several millions of investment for 10 MWh.

> The price of battery storage is dropping exponentially

We're at the flat end of things. Even if this trend continues, there won't be another 99% reduction coming.

> Eventually, the price becomes pretty trivial.

Only if you can scale manufacturing and materials the same way. Hopefully not with Lithium, because that's just not abundant enough.

> The scale we're talking here is not just a shack with a couple of batteries. Even with low prices of today, we're talking several millions of investment for 10 MWh.

1.78 million USD at current exchange rate. Before sales tax, but if you're buying at this scale, you claim that tax back anyway:

https://www.ladeengel.de/Batteriespeicher/Grossspeicher-ab-5...

> Only if you can scale manufacturing and materials the same way. Hopefully not with Lithium, because that's just not abundant enough.

1. Sodium is already cost-competitive with lithium, for batteries.

2. There's loads of lithium all over the place, the hard part of using it is that it's spread out everywhere rather than particularly concentrated. Like, we're talking 150 million tons of "reserves", 250 billion tons dissolved in the seawater, and plausibly 5 quadrillion tons in the bulk of the planet's rock.

> can claim that tax back anyway

You could make hamster wheels an attractive energy source with enough tax refunds. That's not an especially compelling argument when arguing about the global ramifications of a new technology. Tax breaks don't magically make alternative fuel sources better on any given axis. They shift incentives, but that power isn't infinite.

In the EU, all sales taxes are refunded to businesses, it's available for literally everywhere in the supply chain.

It's called "Value Added Tax" in English (UK has same rules despite Brexit), because it works out as the tax on the value you add: Business 1 digs €1 of stuff out of ground, charges their customer e.g. 15% VAT; business 2 buys it for €1.15, claims that €0.15 back always, processes the stuff into €2 of new stuff, charges their customer (in this case) €0.30; business 3 buys it for €2.30, claims that €0.30 back always; etc. all the way to the end customer or export market.

If you're spending millions on power management equipment, you're absolutely a business, and absolutely will get to claim this tax back, and you effectively owe tax only on the net benefit it brings. Electricity is also subject to VAT, though the rates are allowed to vary, and the e.g. UK electricity VAT rate is 5% while the general rate is 20%.

https://en.wikipedia.org/wiki/Value-added_tax#Comparison_wit...

Look at the graph in the article. The trend is clearly log-linear at the tail end in 2024, which is to say, still dropping exponentially. People said the same thing about solar for years, of course. Exponential decreases in cost are apparently hard for people to reason about. As others say in adjacent comments, there's lots of lithium around, and lots of promising work on salt based chemistries for mass storage. Plenty of room for progress.

Chinese companies are building salt batteries now.

> Electricity is expensive to store, especially at the scale we're talking.

An old XKCD what if: https://what-if.xkcd.com/128/

> What in my pocket actually contains more energy, my Zippo or my smartphone? What would be the best way of getting the energy from one to the other? And since I am already feeling like Bilbo in this one, is there anything else in my pocket that would have unexpected amounts of stored energy?

Which in part had:

> A container of butane the size of a phone battery could, in principle, power the phone about 13 times longer than the battery itself could. The obvious question, then, is "why doesn't my phone run on propane?"

...

Also http://www.jefflewis.net/blog/2012/01/how_much_gas_to_charge...

And while that's based on a study from Exon (no longer accessible)... but the math part is math no matter who does the math.

> So, the claim that there's enough energy in a gallon of gas to charge an iPhone every day for 20 years seems pretty reasonable (in reality, when you look at the efficiencies, you won't be able to put all that energy into charging the phone).

> An iPhone may not be huge, but 20 years is a pretty long time. It really just goes to show how much energy gasoline contains, and why it's so useful for powering vehicles.

Toshiba pioneered a portable fuel cell dock for their laptops in 2003, apparently 100cc of methanol produced 12W for 10 hours. A zippo has just a couple cc of fuel. I do wonder how much the technology has advanced in 20 years.

https://www.global.toshiba/ww/news/corporate/2003/03/pr0501....

Ethanol goes into a boring tank, but to be useful that boring tank has to be pumped into a tanker and driven, using more fuel, to somewhere it can be distributed. That's way more energy-intensive than running a cable, so forget storage, just run the cable and let the grid operator take care of the storage at utility-scale.

The cost for the storage still exists and has to be paid by someone. And extending the power grid at this scale is a several decade long undertaking. These things don't pop up by sheer willpower.

The point remains that the costs of solving storage for solar are less than the costs of solving transport for ethanol, especially when you consider how dreadfully inefficient ethanol is as a fuel source, double-especially when you consider how dreadfully inefficient combustion engines are. It's no contest.

recycling batteries is expensive, lead recycling is almost solved (it's not 100% and given it's chemistry, even 1% leaking into the enviroment isn't a good deal) but lithium?

lithium recycling is _expensive_, batteries don't have an universal design to make the recycling a standard protocol... facilities and transportation of recycling/recycled batteries is also not a child's play - i highly doubt, given our grief (think like PET plastic being super easy to recycle yet the amount of it on oceans), we'll make green energy not green, otherwise we would be dropping money on nuclear research rather than technology that worns out in 20-25 years of use and produce thousands and thousands of metric tons of thrash

Why would you use lithium for stationary batteries?

> Very conservatively solar produces 30-50 times are much energy per acre as corn ethanol.

31 times, according to https://www.pnas.org/doi/full/10.1073/pnas.2501605122. That’s from pril 2025, so possibly slightly outdated, but I don’t think technical advances can have pushed that to “very conservatively 30-50 times as much”.

Depending on what you want to do with the energy, you are right it can easily be 50 times as much of useful work. For example, ICE cars turn over 80% of that energy into heat, electric cars less than 20%. That’s a factor of 4 in conversion ratio.

I cant fully trust your numbers but its just feels good if these are accurate.

I had never bothered to calculate the miles-per-year before. My very, very modest rooftop solar does in fact throw off 11,000 actual, real world miles per year for my actual PHEV - so very close to your number. That is a fun way to think about things. Alas, much of it actually goes to waste as the car that would be charged is at the office with me.

My opinion is states like California should enact policies to encourage work place charging. Because that's when the energy mix has the highest amount of solar.

> Meanwhile, more and more food is produced under cover for a lot of good reasons.

(Disclaimer: I know nothing about farming)

I somewhat agree - dumping pesticides and fertilizer into the ground every year and then letting it pollute rivers is low-key insanity. But then you look at just how much farmland is out there and realize some crops just can't be put indoors, probably ever.

There are lots of variables for sure, but I do wonder how much more efficient indoor growing must get to overcome outdoor growing? Land value is vastly different between regions, so does labour, crop type, etc.

p.s. Tom Scotts recent video on strawberries was amazing - special mites to fend off other bugs and UVC light sanitizing was a bit of wow for me.

> dumping pesticides and fertilizer into the ground every year and then letting it pollute rivers is low-key insanity

Ag runoff is certainly a thing.

But also, if you harvest a crop, those are elements that are leaving the field and need to be replenished. Annual fertilization will always be a thing for any crop or combination of crops, if only for micronutrients.

lol, you do know nothing about farming.

They aren’t talking about growing wheat indoors, and when they talk about tunnels it’s a bed crop in a field with plastic over it like you’d see over a box in the city.

Indoor growing has some cool stuff going for it, but you’re not going to grow row crops that we currently harvest headers wider than your greenhouse.

You’re also unlikely to put those under solar, if you’re going to do solar on that patch, it’s probably not worth farming a crop that produces 1000$ per acre under it when the solar is going to be producing way more than that.

If you sell corn you harvested right now you'll get $4.43/bu. Let's say $4.50 for ease of math.

My area averages about 175 bushels/acre for trash soil and closes in on 250/acre for prime River bottoms.

$1125 an acre without expenses is what you can expect in a GREAT year. But that's every year and it's insured against crop failure. The last years that we farmed, about 70% of our gross went to expenses. So figure about $450/acre in profit (mostly to pay for my house and food and what not).

Can electricity compete with that? I genuinely do not know.

Let's ballpark it. 20% capacity factor, 22% efficiency, 50% coverage in the sense of square meters of panel per square meter of land (this depends on your tilt angle).

An "acre" is about 4047m² in modern units, so at "one sun" of 1000W/m² you would get 4.047 megawatts per acre. Multiply by the factors above, you actually 89kW/acre. A year is 8766 hours, so that's 780MWh/acre/year.

Suppose you get a PPA signed for 3 cents a kilowatt hour, US$30/MWh. That's US$23400/acre/year. But that's revenue, not profit. You can compare it to the US$1125/acre/year you give above. So what are the expenses?

The most fundamental cost here is the solar modules. 4.047MW at 50% coverage and 22% efficiency is still 445kW peak. At the current US$0.15/Wp in international markets, that's US$67000 to plant that field with panels, noticeably more than the US$675 you report to plant it with corn.

But, if you're still measuring land in acres, as if we were in the Canterbury Tales, you're probably in the US, where modules cost roughly double what they cost in the rest of the world, due to bipartisan tariffs to protect US fossil fuel interests. And the balance-of-plant costs are typically about double the cost of the modules alone. So, instead of US$67000, you're probably looking at US$300k for those 445kW (or 597 horsepower, or the power of roughly 1100 American-football running backs, if you're more comfortable with those units.)

US$23k per year from a US$300k investment is about 7% ROI, which is probably profitable but not wildly so. And if you don't have a signed PPA, you can expect that revenue to decline, as cheaper panels and power electronics drive the value of daytime generation to zero, and household units that don't need such high balance-of-plant costs reduce demand for utility-scale generation. Also, you can expect heavy industry to move to countries where solar power costs less, reducing demand.

The cost of the land isn't really significant at these investment levels.

You can fit about 200kW in an acre which will average you 300MWh per year.

Your costs are also wildly off. Panels are like 25% of cost. Rest is inverters, mounting, labour and most significant - connection to grid.

This varies a lot by latitude and things like the competence of your construction firm, but, for example, https://seia.org/research-resources/solar-market-insight-rep... gives cost breakdowns for the average US “turnkey installed price” of solar power at the time, coming in at 98¢ per (peak) watt for “utility-scale fixed-tilt”, of which about 40¢ is the PV module itself. So, at least at that time, in the US, 41% of the cost was the panels, not 25%. So I don't think my estimate of 33⅓% was as "wildly off" as you do.

That might have changed if cost reductions in other parts of solar power plants have lagged behind cost reductions in the panels. But actually mainstream PV modules cost exactly the same today as they did in Q2 of 02024 (https://www.solarserver.de/photovoltaik-preis-pv-modul-preis...), which is when the report is about, so, if anything, we'd expect to see them taking up a larger fraction of the total cost, since the other components presumably have gotten cheaper as they've moved down the learning curve. (The "low-cost" and "high-efficiency" categories did get cheaper, but, as I understand it, the former are not generally used for utility-scale plants.)

The connection to the grid is a question of politics, not cost and resources.

> Can electricity compete with that? I genuinely do not know.

Here's the fun thing: if humanity were one united species instead of a bunch of tribes willing to fuck each other up every few decades, we might just go and grow crops where they grow the best, maybe with a bit of redundancy to guard against natural disasters and whatnot.

But unfortunately we are not, and so we have massive overproduction going on, which in turn means without insane amounts of subsidies (25% of the EU budget goes to farm subsidies!) farms could not survive.

If the subsidies were killed, even shit solar panels would yield more money than a lot of land could yield with growing crops.

> For few years, then every solar farm would go bankrupt all while food supplies gone.

If there is one thing effectively infinite, it is humanity's demand for energy, particularly with the growing demand from switching transportation and heating over to electricity.

And food supply wouldn't be gone, it would just migrate e.g. to Ukraine.

> humanity's demand for energy

Which was flat for the last decades in the Western world until the AI boom started. The demand was increasing, but efficiency gains were negating it. Generation was increasing ~2% per year.

HN is probably over-indexed on people living in high-density cities, which might explain why tech like this and also things like vertical farming are popular here. However there's almost no dimensional constraint for farmland in the United States. We have vast amounts of it and there's really nothing to be gained from "stacking"

Often these "solutions" introduce more problems than they solve. One example being a solar farm designed to be grazed by sheep where the panels are so low to the ground that farmers can't bring in tractors and cut hay when the ruminants are gone for a season.

The best solution is still to put solar panels and farmland in different places where each can be optimized without concern for the other.

> The best solution is still to put solar panels and farmland in different places where each can be optimized without concern for the other.

There's significant evidence "add solar panels" is an optimization to at least some kinds of farmland.

> farmers can't bring in tractors and cut hay when the ruminants are gone for a season

That season is typically "winter", and you wind up without much hay to cut at that point.

True but you also need to make those pretty robust and probably put deeper into the ground because the shear load increases significantly. That then eats into the actually money saved for putting the whole investment together.

As much as I want solar everywhere - it far from a sure thing for making/saving money.

> True but you also need to make those pretty robust

they also have to be able to get "bumped" by a brush hog, plow, and whatever else without collapsing and taking down a bunch of panels.

Mowing bots are likely a cheaper solution. But kinda silly when sheep exist.

> You do realize

Please omit snarky phrases like this from comments on HN. The guidelines make it clear we're trying for something better here. https://news.ycombinator.com/newsguidelines.html

Believe it or not cattle is a low margin business and farmers can't buy hay (from a non-PV field) and sell meat at a profit. Ranchers cut hay to get their pastured cattle through the winter. They can't have portions of their field unreachable by a tractor. Reasons like this are why this type of tech will always be popular on HN but they just can't figure out why farmers don't want it.

> Ranchers cut hay to get their pastured cattle through the winter. They can't have portions of their field unreachable by a tractor.

No one's banning hay fields. You can do both.

https://www.canarymedia.com/articles/food-and-farms/wheres-t...

"The solar canopy also protects the grasses, keeping them green and dewy, even as nearby fields blanch and crisp in the sunlight. Shallanberger rotates the herd every few days, a key tenet of regenerative farming philosophy, so they munch on fresh grass while the rest of the field grows back. They move through all 15 paddocks in about 45 days; if the site relied on mechanical mowers, they’d trim every 45 days, too."

"Vegetation management is one of the most significant costs for solar plant maintenance in the Southeast, Shallenberger said. In the first six months, the cattle took care of about 75% of the mowing — he had to bring in conventional equipment for some woody weeds that the cattle don’t care for. Once the pasture is more established, the herd could handle up to 95% of the site’s mowing needs."

> Reasons like this are why this type of tech will always be popular on HN but they just can't figure out why farmers don't want it.

Farmers come in different sizes, shapes, locations.

The largest https://en.wikipedia.org/wiki/Cattle_station is several times the size of the state of Rhode Island, and chances are there're some spots where a bit of shade is welcome. I can also assure you no one's mowing/haying that size a property.

I bet the cows appreciate the shade!

> They move through all 15 paddocks in about 45 days; if the site relied on mechanical mowers, they’d trim every 45 days, too."

What do you think "trim" is here, and why do you think anyone would do it?

How much do you think a hay field would grow in six weeks?

> What do you think "trim" is here, and why do you think anyone would do it?

The animals are doing the trimming instead of the mowers. This isn't super complicated logistically; each takes tall grass and turns it into short grass. You can rent goats to clean up shit like poison ivy, even.

> How much do you think a hay field would grow in six weeks?

The one by my house grows maybe a foot in that time, which is why they rotate pastures. Even a handful of horses can keep an acre worth of pasture quite well cropped.

You don't "trim" hay fields. You trim lawns.

Really? That’s the dunk you were trying to work towards?

The animals keep the grass and weeds under the solar panels trimmed, saving on mowing. This also provides food to the animals, who love grass, meaning you don’t need as much hay during the spring/summer seasons. The cows get fed, the solar field gets maintained, and the farm gets energy output as a bonus.

Leave a grassy field untrimmed for a few months and guess what you wind up with? A hay field.

Why should the tractor be the old tractor when we are talking about a futuristic PV field? There is already a market for these autonomous tractors and seems they are all about half the height of a traditional tractor, basically the same vehicle with the cab cut off. Then for specifically mowers they can get pretty slender. I imagine a purpose built mower/hay harvester could be very slim. Huge advantage for the farmer if these are electric as well; power would be "free" from pv field and you only need a single technician or mechanic perhaps to maintain this operation.

I've seen farmers on here, and it's a trivially verifiable fact that some farmers are using agrivoltaic approaches.

Nor are farmers immune to the "vote against your own interests" political bullshit that often comes up around renewables. Look at how many voted for the guy who started a trade war as a thank you.

(Plenty of bakers here, by the way. I used a literal ton of flour during COVID keeping the neighborhood supplied with sourdough. And I give hay to horses ~5x a week; I've seen what animals can do to a grassy field.)

I'm going to guess that all you can do yourself is "code" and you've never actually farmed, wired a house or processing plant, can't gas fit pipes, never studied civil engineering, can't pave a patio or build a brick BBQ, and have never submitted policy papers to local government.

If that's the case, then I suggest you work on that and broaden your life experiences.

The case the article makes is for “devoting 1% of farmland to agrovoltaics”, that seems arguably very low and non-intrusive. The loss of some micronutrients is more worrying than the cute notion that industrial-scale farming bothers with sheep grazing.

We could grow some crops in that 1% of land and provide reams of clean power to the world. And the more we restore land to nature, as opposed to our mono-crops and cows, the more co-benefits we reap.

Why should the tractor be a 1950s tractor pulling a mower attachment? If we are talking about something so techy as a solar panel clad farm, it is definitely going to have electronic robotic mowers. These are already used in commercial landscape setting and barely 2 feet tall.

> These are already used in commercial landscape setting and barely 2 feet tall.

Can they mow a 1,000 acres and get through ruts from feral hogs and everything else? If so, then that's awesome (i really don't know) but you have to think of the scale.

I mean they are used on golf courses which are quite large acreages. I don't see why not. What makes the tractor manage those conditions is not really it being a sensitive instrument, but being a sort of crude and heavy dgaf machine. You can certainly make that in a slimmer package than one that needs the farmer to sit up high and has had the same "bodyplan" for what 150 years maybe, just because that's how its always been done not for any other reason, and no real pressure until now to actually constrain the vertical space of the tractor.

Already do

This need not work for all farmland to be useful.

As an example where I think it would work: industrial greenhouses.

This makes sense, as there have been quite a few VC-backed vertical farming (mostly for vegetables, as you can’t grow grains AFAIK) startups which have shut down in the recent few years.

> cut hay when the ruminants are gone for a season.

But surely only certain places need to do this? for the UK, you need to make hay for the winter, assuming that your meadows flood, or are otherwise muddy. But if your in one of the more temperate areas of the southern USA, surely you don't need to do that?

Up here in Scotland (can't speak for England, it's half a day's drive south of me just to get to the border, but watch Clarkson's Farm) we tend not to make hay very much these days. Mostly we make silage, which is where you cut long grass but instead of allowing it to dry into hay you bale it up while it's still green and wrap it in plastic sheeting. It undergoes anaerobic fermentation, which preserves a lot more of the nutrients, and it doesn't spontaneously combust if it's still a tiny bit damp when you store it.

The silage that you get, then, is basically like a kind of grass sauerkraut, and smells exactly like you'd expect.

That combined with "draff" - distillery mash, the spent malt from brewing "pot ale" for making whisky, and a certain amount of shredded sugar beet tends to make up the majority of winter fodder.

Draff is great because it's still fermenting slowly and generating a lot of heat, so the cows are eating hot food in the winter. It's mostly the fibrey bits of the barley malt, which we can't eat but which cows and sheep - having cellulase in at least one of their stomachs - do incredibly well on. It's absolutely no use for anything else, humans can't eat it and it doesn't really compost down. It just rots, stinks, and emits masses of carbon dioxide and methane when it does. Far better for the environment to lock all that up in a cow.

Ideally your fields don't flood because you plant crops in the autumn that stay in the ground over winter to germinate in the spring, and if they get flooded that's it, you've lost the lot.

You tend not to see soya-based or other leguminous food here very much, because it's expensive, it has to be shipped halfway round the planet, and it's ineffective - you get shitty meat that no-one wants to buy.

You need the cows to graze pasture, chew up the grass, break down all that tough cellulose and poo it out as incredibly highly refined fertiliser.

We eat, just about everywhere in the world, because there's six inches of earth, it rains sometimes, and cows and pigs shit solid gold.

> Far better for the environment to lock all that up in a cow.

Don’t they just.. release it?

Everything does. The "cow farts" thing is a bit of a myth - it's based on guessing how much methane farts out assuming every atom of carbon in what they eat turns to methane.

It doesn't, of course, the most of it gets turned into cow.

> Far better for the environment to lock all that up in a cow.

This works for trees, which you can turn into, say, a house, where it might last hundreds of years.

I'm curious about how you think the physics of it work for a cow.

A pile of solid carbohydrates (grass) can rot and go largely to water and released gases OR it can be eaten by an animal and goto some water, some gases, some poo, and a reasonable amount of energy and some conversion to meat for growth.

Methane release varies by animal type: https://reporter.anu.edu.au/all-stories/kangaroos-the-soluti...

Understanding why is ongoing: https://www.uow.edu.au/media/2015/why-kangaroos-really-emit-...

> A pile of solid carbohydrates (grass) can rot and go largely to water and released gases OR it can be eaten by an animal and goto some water, some gases, some poo, and a reasonable amount of energy and some conversion to meat for growth.

That meat gets eaten and largely turned into poo and gas (as byproduct of using up that stored energy), yeah? You're sequestering it maybe for a few years; meat cows live about two years.

> “Kangaroos have a very different stomach from that of ruminants such as sheep and cows,” Professor Clauss said. “We think that the methane is low because of the way food moves through the kangaroo stomach, and not because of a unique gut fauna.”

> Dr Munn and Professor Clauss are critical of efforts to try to reduce greenhouse gas emissions from ruminant livestock by replacing their gut fauna with that from kangaroos or other low-methane emitting animals, which they believe is unlikely to succeed.

You're not raising kangaroos in Scotland, right?

No one raise kangaroos here, they raise themselves: https://www.youtube.com/shorts/YzzXsTF25Qk (black dots on ground are kangaroo poo)

So yes, you're correct - I'm not raising roos in Scotland, but we do look into ruminants, biomes, etc here.

These are complex chains that make up the surface level carbon cycle. Not every path leads to carbon dioxide / methane production, the gas creation ratios can be tweaked by the paths taken.

The problematic carbons are those that are additional - those once buried across the course of millions of years, some millions of years ago and now being bought to the surface in an extremely short timescale (one century and half, roughly)

This all goes to your question if you care to look into it.

> No one raise kangaroos here, they raise themselves…

In Scotland?

> The problematic carbons are those that are additional - those once buried across the course of millions of years, some millions of years ago and now being bought to the surface in an extremely short timescale (one century and half, roughly)

Meat production accounts for somewhere between 15 and 20% of human emissions. It is a significant part of the problem.

> the gas creation ratios can be tweaked by the paths taken.

To a point. Producing and consuming meat is gonna emit carbon. This isn’t disputable.

> In Scotland?

Already answered. Engage brain, treat it as a puzzle.

> Meat production accounts for somewhere between 15 and 20% of human emissions. It is a significant part of the problem.

Is it? Or is it just cycling the carbon in the land / sea close surface layer?

> To a point.

The point being it is something that can be modified and addressed.

> Producing and consuming meat is gonna emit carbon.

Recycle carbon, rather than dredge up and release fossil carbon might be a better framing for any wanting to get to the root of the issue.

> and consuming meat

Shooting and eating kangaroos, feral camels, goats, donkeys, clean skin bulls, etc. somehow adds in a significant manner to AGW ?

Are you _sure_ about that?

> Or is it just cycling the carbon in the land / sea close surface layer?

We know it isn't. Immense amounts of crops like alfalfa are grown, with extensive fertilizing via petroleum products, to feed inefficiently to cattle.

> The point being it is something that can be modified and addressed.

It's enough of a fight over clearly-better extant solutions like solar. The near-term fix to climate change isn't gonna be evolving cows to burp less.

> Recycle carbon, rather than dredge up and release fossil carbon might be a better framing for any wanting to get to the root of the issue.

This describes a tiny percentage of cattle raising practices.

> Shooting and eating kangaroos, feral camels, goats, donkeys, clean skin bulls, etc. somehow adds in a significant manner to AGW ?

This describes a tiny percentage of meat production. You're not going to feed Australia off the kangaroo population, let alone the world.

> Meat production accounts for somewhere between 15 and 20% of human emissions. It is a significant part of the problem.

Only if you assume that the finger-in-the-air guesswork around how much emissions you get from livestock is correct.

What do you think would be better?

> What do you think would be better?

Less meat? 10-50x as many calories per ton of CO2 generated.

the cow is part of it, but not the whole part.

A well managed grass meadow is a carbon sink. As the parent says, the cows graze and shite which causes more growth. if you rotate your cow out before they eat everything back to the earth, it makes the grass grow thicker.

because not all of the grass is eaten, a fair portion is left to eventually die off and form the next layer of soil, trapping the carbon there.

The reason why cows are considered global warming is because forests tend to be felled to form feeding lots. Or in more tropical areas, grasslands that then decay precipitously. (see dustbowl causes in the prairies and why the USA spent a huge amount on soil preservation)

Its not a one size fits all thing. In Aus, over grazing leads to desertification, which causes sun baking. This means the soil is baked into a water resisting layer that causes flash floods. But, because its flash flooding, the water isn't dwelling and soaking in, causing the place to get drier.

In Yorkshire, overgrazing lead to the tree-less desolate expanse which is the dales.

In the lowlands of Scotland, they went and planted a shit tonne of pine to try and compensate/bring back forestry, but that turned the soil acid and killed the streams.

> The reason why cows are considered global warming is because forests tend to be felled to form feeding lots.

This is not the sole reason, no.

Immense amounts of fossil fuel (and water) go into fertilizing alfalfa, corn, etc. fields that are grown to inefficiently feed cattle with.

Okay, and how do you propose to grow trees there?

What, among the solar panels?

You grow the trees elsewhere. Like we currently do. Forests make good carbon sinks.

Huge isolated fields of solar end up with the same problem as nuclear: they introduce multiple single-points of failure.

The source can be attacked, the transmission infra can be attacked, the delivery point can be censored.

I think most people want highly distributed, reliable, affordable power. That's why off-grid tech is experiencing such a boom.

I live in a 36' skoolie, so I'm nomad-indexed, but I can confirm that over the past 10 years or so, most RV-lifers have transitioned their focus from recreation / comfort to off-grid experimentation. Essentially everywhere I go in the US, if I'm camped near others, they are going to have minimum viability for boondocking. That was not the case when I started.

Especially amidst the current political instability and apparent looming collapse of the US state, one of the simplest things that most of us can do is stabilize off-grid power in our neighborhoods, and that is quietly happening all over the place.

So, the role of vertically integrated solar (both literally and metaphorically) has more to do with the grid shape that serves our stability needs, and less to do with large-scale differences in efficiency.

Panels are cheap enough that I don’t really see them being a great target for drones. You can dig power lines under the ground and shield them?

What are we comparing against exactly that’s more resilient?

> The source can be attacked, the transmission infra can be attacked, the delivery point can be censored.

Who cares? One isolated field of solar represents a negligible amount of power at grid scale. Nobody is going to bother to go around attacking each individual field because the "ROI" of attacking a high-voltage transmission line (the kind that brings power from multiple thermal plants to a city) is so much higher.

Attacks scale in the drone age, infrastructure left where nobody’s looking at it is a vulnerability. Solar stacked on an active farm has the benefit of having eyes on it constantly - detection, repair and recovery cycles are dramatically shortened.

Totally. Solar stacked _anywhere_ has this benefit.

Those are the result of decade of negligence.

I hope anyone building networked infrastructure TODAY would take security more seriously.

And if they don't? Their investment wouldn't have survived in today's world wherever it went.

They don’t. Which was my original point.

> One isolated field of solar represents a negligible amount of power at grid scale.

Maybe I was unclear: that's exactly my point! That's the problem with grid scale for most everyday uses.

In 2026, it's fairly trivial to have a setup such that, if "the grid" fails, I don't even notice for days. That's a nice feature! And it makes sense to build out communities that way from now on.

"The grid" is great for industry, but for residential, micro-grids are clearly the future. Allowing the state and the electric company to cut us off - intentionally or otherwise, let alone having no power during a disaster when it's needed most, is a very silly thing to trade for a tiny efficiency increase.

I sleep well at night knowing I have four bigass AGMs under me.

>everywhere I go in the US, if I'm camped near others, they are going to have minimum viability for boondocking

Can you elaborate, please? What exactly has changed, and over what time period?

I bought my bus in 2015, so my personal picture is of the past 11 years.

The big changes seem to have been:

* Better / more varied solar panels

* Lithium batteries (which I don't use for a house bank, but still benefit from by dint of them having driven the price deep-cycle lead batteries down)

* USB-C everything

When I first started this lifestyle, almost everyone had lead-acid batteries powering an inverter, and a zillion wall warts converting power back to DC. Some people had solar for sure, but a solid majority only camped where they were able to plug in.

At festivals, powered sites sold out quickly and at a premium. Dispersed camping in national forests was the purview of tent campers, truck campers, and people who don't use much power (ie, not a ton of remote workers). New campgrounds always focused on power pedestals and seemed to regard that as the MVP.

Now, festivals are a sea of solar and/or off-grid-cooled beers. Campgrounds are often a de-facto swap meet of usb-c oddities (I have a USB-C coffee grinder - what a world!). Dispersed camping in national forests are often transient standing desk communities. Nary an inverter in sight - everything is direct-to-USB-C.

The difference between most people needing to plug in within a few hours in order to have their basic comforts vs. being able to live indefinitely without the grid has significantly changed what it feels like to be on the road.

This is silly. Solar fields are cheap and easily replaced. The grid already has enormous single points of failure that are actually hard to replace - they are called substations.

But as we refine and revise power delivery to our communities, why then do we want to emulate the substation model?

Tiny deployments of off-grid solar beat the pants off that model.

Sure, for individuals or pairs roaming about in an RV, small homesteaders, etc.

How many tiny off-grid solar deployments are required to power the people and industries of a small city of two million?

Many acres of grain are required to feed such a city, why not many fields of solar panels, community batteries (roughly one per 1-2 hundred houses), smart grids, etc.

Yeah, these are the real questions IMO.

I think we're gonna see more and more EVs double as off-grid power banks, for example.

> I live in a 36' skoolie, so I'm nomad-indexed,

Cool, cool.

So what do you run the engine on? How many single points of failure?

I have a 7.3 powerstroke (actually T444E - the year before Ford bought Navistar!), and I haven't modded it yet, so I run just plain diesel.

Mechanically, almost every component is a single-point-of-failure: drivetrain, brakes, cooling system, etc.

But I don't actually move all that much; I only move from place to place maybe a dozen times a year - less some years.

And while I'm stationary, it's pretty easy for me to have fully off-grid power. And a composting toilet lasts me a full loop around the USA without needing to empty the solid container.

But I didn't mean for my point to be about mobile living, just identifying that one of the main benefits of solar as opposed to nuclear is that control over power distribution can be scaled radically downward.

Solar is great, and right now at mid-day from my 5kW of panels I'm currently getting my winter average of 30 watts.

So it looks like nuclear would be a pretty good option here.

Some of us are interested in ways to do things outside the US. Yes, even some who live in the US.

You know there's a whole world outside the US... AND most places do not in fact have those vast amounts of open land

In the theorical sense, sure. We could cover all of the world's needs with a solar panel in the Sahara that's 700 km on each side and handwave the transmission lines for that.

The real world however, a farmer owns a specific plot of land, has $w of capital in the back, owes $x in loans, owes y tons of crop, owns z tractors and seeds. Without centralized planning, plopping down solar panels in an optimal place isn't how the real world works.

That is exactly how the real world works, as evidenced by the enormous number of purpose built solar sites and the vanishingly small number of dual use solar fields.

No it doesn't. Fossil fuels are still roughly 80% of the world's needs and solar is something less than 5%. We are making progress in that area but I wouldn't really call that "working", imo.

surely someone is busy breeding the tastiest salad that just can't survive being transported for more than 30mins so you end up NEEDING that stacking right in the city where all the michelin star restaurants are... get the rich to fund and perfect the tech, as "green" as it can be, get some patent under your belt for your investor (mars garden anyone?)

> The best solution is

is it?

if your initial reaction is we have tons of empty land why would we ever build solar panels over a farm?

this isn’t an either-or question. a farm owner may want to add some revenue with electricity generation. just like a hospital may want to cover their parking lot to offset costs.

at giant scale do these solar location choices optimize the absolutely best use of land for cheapest possible electricity generation? no. but at small scale it can make sense for these individual owners

https://electrek.co/2026/10/05/six-flags-has-installed-one-o...

I believe that, while a cool technological innovation, the cost of installing and maintaining these panels will be significantly higher than doing the same on open land.

The article’s biggest claim is that devoting one percent of US farmland to agrivoltaics could cover 20 percent of the country’s electricity, pointing at the Texas to Nebraska to California corridor, which is exactly where big mechanized farms are most common.

They run large equipment (combines, sprayer booms, center pivot irrigation systems[1], etc). To keep that working under panels you need tall posts, wide spans, and a layout that matches the equipment paths, which would push structural cost significantly above a ground installation. All maintenance would require a boom truck, not just a ground crew. And center pivots in particular (very common) need an entire circle cleared for the system to pivot, meaning a multi-acre span with no posts for the pivot to hit, which is simply infeasible.

That’s before accounting for pesticide spray and dust on the PVs, or the logistical burden of running PV crews through a working farm.

It’s also worth noting that the study itself was broccoli, which is hand harvested and about the best case crop for this. Even so, the broccoli took 25 extra days to mature. On a farm running multiple rotations a season that lost time has a real cost, separate from the structural costs.

This innovation has a lot more promise on smaller plots. Co-ops, market gardens, specialty crops, and the like that don’t rely on large equipment. I’d be surprised to ever see it on a large farm.

[1] https://en.wikipedia.org/wiki/Center-pivot_irrigation

> large equipment (combines, sprayer booms, center pivot irrigation systems[1], etc)

Something I've always absent-mindedly wondered about when agrivoltaics comes up is integrating a gantry/rail system of sorts for the farm equipment. It's definitely infeasible for many reasons, but it's fun to think about. Instead of equipment pulled by tractors, have the equipment ride above the field on rails, held up by the same poles the solar panels are on.

Maybe today but with the rise of automation, who knows?

Center pivots are mechanical automation. They replaced traditional hand-moved sprinkler lines and automatically sweep the entire field at a defined rate. The concept is over 100 years old and has stuck around because of how efficient it is.

Unless we intentionally replace them with less efficient automation, it’s a hard sell.

It’s really more of a physics problem than an automation problem.

Center pivot irrigation is hardly universal - its main use is in low / sparse rainfall areas in order to deplete the finite resource of the water table. There are already strong signs a number of significant basins are in terminal decline from agricultural use.

There are no universal one setup suits all solutions here.

One advantage of large scale agrisolar projects (trialled since at least 2020) is better moisture retention through shade of increased condensation drip.

It's a balancing act - you appear to have a position hard up one end of a see saw.

You can farm and do industrial scale solar on the same land. It works extremely well for lamb herds, shade tolerant crops like strawberries, and greenhouses. I'm extremely interested in this area and actually starting some personal projects where I live, around agri-solar that is actually farming.

any recommended reading resources or documentation of your projects? building a resource database on this field and don't personally know anyone with experience, especially being in the NE

Perhaps of interest.

March 2021: https://assets.cleanenergycouncil.org.au/documents/resources...

Watch the Australian Agrisolar CRC partners: https://www.cooperativeresearch.org.au/resources/about-the-c...

Optimization for land area in agriculture is already a catch-22 type affair: We subsidize the planting of corn to produce ethanol -- one of the most inefficient forms of solar energy 'harvesting' possible. So going directly to electrical harvesting while retaining the ability to grow high-value crops is certainly still advantageous...

To put some numbers: ~40% of the corn grown in the US (approx. 5.4 billion bushels out of roughly 14.9 billion bushels total production) goes toward ethanol production

No sure if the reference to catch-22 was meant to be specific but this is one of my fave quotes from the book:

> His specialty was alfalfa, and he made a good thing out of not growing any. The government paid him well for every bushel of alfalfa he did not grow. The more alfalfa he did not grow, the more money the government gave him, and he spent every penny he didn't earn on new land to increase the amount of alfalfa he did not produce. Major Major's father worked without rest at not growing alfalfa. On long winter evenings he remained indoors and did not mend harness, and he sprang out of bed at the crack of noon every day just to make certain that the chores would not be done. He invested in land wisely and soon was not growing more alfalfa than any other man in the county. Neighbours sought him out for advice on all subjects, for he had made much money and was therefore wise. “As ye sow, so shall ye reap,” he counselled one and all, and everyone said “Amen.

That's a great plan... except that we're degrading the soil in the process, significantly reducing it's long-term growing capacity to maximize short-term profits.

I'm all about sound long-term land management and subsidized capacity. The current system is not that.

> this isn’t an either-or question. a farm owner may want to add some revenue with electricity generation.

Also: Many plants don't want/need full sun. In fact, they adapt by varying production of a chemical called zeaxanthin throughout the day to manage the amount of energy they take in.

Partially shading crops with bifacial panels (which are semi-translucent) can be beneficial to the crops as well as producing energy.

https://www.science.org/content/article/too-much-good-thing

Initial reaction is how do you harvest? Is the farm well connected to the grid? Is the cost of making this practical just much higher than land. Land is cheap in the scheme of things here.

https://farmbuy.com/1595-florina-road-katherine-nt-0850-4368...

1% of panel cost according to Gemini.

Sure, but given that a 100 acre corn farm in Ohio would make about $80k in revenue and if you're lucky about $40k in profit

A 100 acre solar plant in Ohio would make well about $1m-$1.5m in revenue

Why would you increase the cost and complexity to try to increase your revenue from $1-1.5m to a massive $1-1.5m?

Or you could just lease the land to a solar operator for about $100k a year, with no expenses

It's a solution looking for a problem.

Don't know about the US, but where I live farmland is restrictively zoned to preserve its agricultural use. You can't just turn prime cropland into a (normal) solar power plant, but perhaps you can get away with this dual use trick.

I wonder how little farming you’d have to do if this did count. Does letting a few sheep walk around a solar farm count? Growing a few strawberry plants? If the economics from elsewhere in thread are accurate, the farming feels like it would add 0 value other than the regulatory dodge, and would therefore be minimized.

> Don't know about the US, but where I live farmland is restrictively zoned to preserve its agricultural use

So central land use planning? Rural America won't be that Commumist -- not even by law, just look at the way it votes.

Freedom means a farmer can do whatever they want with their land

Freedom-loving, R-voting America is full of restrictive zoning. I don't think it's necessarily the contradiction you make it out to be. Especially if, like here, the government doesn't tell you what or how to farm, only that farmland is for farming.

> Freedom-loving

> restrictive

So which is it?

Yes, that's the irony.

Solar plant in Ohio will likely require 50m in grid connection. If you find grid connection near the city the land there is likely more expensive and not growing corn but something more substantial.

What I'm saying - these dual-use agrivoltaics are for higher-margin crops, where land is somewhat constrained.

> Solar plant in Ohio will likely require 50m in grid connection.

there needs to be some way to harvest and transport electricity like you do corn or some other crop. Like an 18 wheeler size lipo that is charged up and delivered to a train of lipo cars and discharged. Then that train goes somewhere and connects to the grid and offloads all that electricity. Rinse/repeat. It's not as efficient as directly connecting ot the grid but maybe it's more feasible than waiting years for a grid connection.

little known fact: US currently grows a lot of corn for ethanol production. If we replaced that all with solar panels we'd have plenty of electricity. The solar vs farm debate is usually framed as a tradeoff with food production but that's not really true

https://www.anthropocenemagazine.org/2025/04/new-study-compa...

> The USDA now expects 5.65 billion bushels of corn to be used for ethanol production in 2026-27

> The department has raised its corn production forecast by 234 million bushels to 16 billion bushels.

https://bioenergytimes.com/usda-raises-2026-27-us-corn-use-f...

About a third! Way more than I thought. I wonder how much of that would have to be covered in panels to get the same energy.

you don't even want to aim for the same energy. With pure solar you need to aim for about 4x nominal output in order to approximately match the utility of something that meets that nominal output at essentially any time like, for example, a natural gas plant. We make about 1.2 giga-gallons of ethanol per year [1] (phew quite a unit, there). A gallon of ethanol has something like 76k BTU/gallon[2]. When we burn Ethanol in an ICE we can usefully extract about 25% of it's energy into rotation. That leaves us with about 5.5 kwH of useful energy per gallon of ethanol. If my orders of magnitude aren't wrong that's something like 6.6 twH which isn't that crazy, considering last year the US make something like 300twH in utility scale solar output. so maybe an additional 25% addition to our solar production.

[1] https://www.eia.gov/petroleum/ethanolcapacity/ [2] https://afdc.energy.gov/files/u/publication/fuel_comparison_...

I wonder if we are depleting the soil to create all that corn. I really don't understand how the lifecycle of soil works, and maybe it's time to go off and ask AI...

depends on how its done, but almost certainly yes.

soil is a living thing, and varies by location. Clay, loam, sandy, etc etc. Then there is a layer of fungus that forms filaments. The roots of the plants grow into this, and then the invertebrates move shit about creating voids and pockets of nutrients.

ploughing can be disruptive to this. but more likley pumping pesticides and herbicies, along with moving the water table causes it to die off leaving only part of the biome behind.

Basically think of it like your intestines. You can live with a "clean"[1] gut, but you'll have the shits constantly, which'll make you dry and windy. Same with soil.

[1] think post antibiotic.

The article I linked claims 3.2%, which seems incredibly low, but maybe ethanol production is really just that inefficient.

> little known fact

It is well known fact, that US do that so 20% of its population wouldn't die from starvation over the next 30 years with significant probability.

One thing the article doesn't mention is that some plants prefer a little shade.

So while broccoli yields may have "held steady," it's possible they could make even more gains elsewhere where it might normally be too sunny. So leafy vegetables like spinach might be doing equivalently fine under the magenta shades in New Jersey, but might actually be even better in Texas.

They certainly do mention this:

> Broccoli cultivated under them grew more slowly, requiring an additional 25 days for harvest, but produced roughly the same yield. Meanwhile, these magenta sunscreens improved the microclimate below, reducing the “vapor pressure deficit”—a measure of when plants need to halt photosynthesis to avoid excessive water loss. This may have improved the plants’ efficiency in converting sunlight into plant biomass, which increased by 2.8- to 4.5-fold compared to unshaded plants.

> The shaded plants’ levels of macronutrients such as calcium, magnesium, and phosphorus were either higher than or similar to unshaded plants, while levels of some micronutrients such as iron, copper, and zinc were slightly lower.

I think you're missing the point made above: the paper compares apples to apples (broccoli with and without shade) for good reason, but the ability to cool the microclimate may enable crop substitution that has better output/value in areas where it is normally too hot for that crop.

This isn't something that's particularly obvious unless its pointed out, poly tunnels work on two fronts:

1) extend the growing season/climate control

2) scatter direct light into bright ambient light meaning that plants aren't scorched.

"leafy" plants like pumpkins, tomatoes, cucumbers etc "wilt" when in direct sun. they go floppy to stop evaporation. THis means they don't grow as fast. If you even out that light so its not directly heating the living shit out of the leaves, they grow faster, because they have less time in stress.

I find the physics of wavelength-dependent materials properties oddly satisfying. You can do clever things like this, extracting energy from different parts of the spectrum by combining materials and conversion processes. You can beam waste heat back to space through the atmosphere’s “infrared window”. You can explain global warming from first principles. Fascinating stuff!

One thing I’m curious about this from the plant perspective - we’re pretty sure we’re passing everything relevant down to the plant, but nature doesn’t normally leave signal or energy lying around without leveraging it somewhere, so what don’t we know about how the broccoli use the parts we’ve been assuming they don’t?

Industrial (or home) grow lights are often already red and blue spectrum focused since those are most efficient for photosynthesis. There’s plenty of research on those if you’re curious

As far as I know, plants are not usually limited by sunlight, but CO2. Grabbing more wavelengths is not going to improve their growth potential.

Plants are green because they _reflect_ non-magenta light! This energy is wasted. If you saw artificial grow lights, they are now often magenta-colored exactly because the green part of the spectrum does nothing, and you might as well save some energy.

These panels absorb that light before it gets to the plant, so it's a win-win.

Sorry, but that's not how it works. Energy is energy, and we can measure what's reflected. Chloroplasts _themselves_ are green, btw. That's where their name comes from.

Why plants are green is a mystery. There is no accepted explanation. A compelling theory is that during the first ocean oxidation event, dissolved iron started crashing out as iron oxide, which strongly absorbs the green light.

I sure hope you’re right.

I feel the same way about how fiber optics can create bandwidth by just slicing up the spectrum for different channels of data (my rudimentary understanding anyway). I like how even after all this time we find new and clever ways to work with light.

Even more wild than spectrum slicing is polarisation encoding multiple data streams on the same wavelength.

Is that something in practice (and does it have a name?)? (The thought tickled my brain as QAM/PSK but for light...ish)

QAM can absolutely be used in fiber optics communication. Encoding and decoding systems are complicated (I won’t pretend to understand it), but it exists.

Example of a research paper using it: https://www.researchgate.net/publication/290224766_Investiga...

Radio is just low frequency light, so all of the same encoding methods apply as-is.

I meant it makes sense! I just never considered it and it's a nifty thought

And then doing amplification on that light without converting it back to electrical signals.

fiber optics doesn't slice up anything. it's just a pathway for light to travel.

Wavelength-division multiplexing[1]... it's what they use with fiber-to-the-home to get bidirectional signals with a single strand of fiber. Or the big-boy version is DWDM which ISPs use to stuff dozens of customers on a single strand.

You might also be interested in https://phys.org/news/2026-11-air-holes-silicon-wafers-flat....

[1] https://en.wikipedia.org/wiki/Wavelength-division_multiplexi...

I'm current taking composite construction certification courses because modern manufacturing provides for customizing the material for very specific uses. Low volume production with very specific mechanical and physical properties.

Wait we could reflect back infrared heat into space and still collect solar energy as electricity - so doing two jobs at once in, say, a desert.

Re-greening at a profit?

Careful engineering can help here.

Reflect back shortwave IR sunlight below the bandgap of the solar panels.

Make the solar panels "black" at longer IR wavelengths corresponding to the temperature of the panels and to IR windows in the atmosphere, to maximize emission of heat back into space.

It would be challenging but theoretically possible. You need very clear skies for the infrared heat not to be trapped by clouds

Are there realistic ways of harvesting vegetables at scale that are underneath mounted solar panels, with all their supports?

Or is the idea that there aren't now, but they could be built?

I'm just imagining that you are going to need a lot of vertical clearance for tractors, and support posts will have to be widely spaced enough that the horizontal beams supporting the panels will have to be quite strong, and that at some point this is less solar panels in a field, and more like constructing a building with solar panels on its roof.

> Or is the idea that there aren't now, but they could be built?

It's hard to see how this would work well with corn, since corn is pretty tall, corn harvesters are pretty huge, and putting panels even high enough for a different set of smaller, realistic harvesters would still require supports that I can't imagine would be cost effective given all the other hurdles they would cause.

Other crops like cotton, alfalfa, and hay aren't as tall, but have the same harvesting problems.

Most harvesting efficiency gains are directly tied to GIGANTIC machines. Farming is insanely efficient and competitive. It's hard to see how smaller machines could be viable and no one would have discovered it until this tech.

I'd guess there is far more potential in grazing land (unrelated to this tech), which is already actively being developed at scale.

The good news is that as someone else pointed out, we mostly grow corn for energy, so in a way, this is more about getting the ground we use for corn back than it is getting more energy.

We are right at the point where fully automated harvesting machines start to gain ground. And removing the operator (or moving the operator outside the machine) allows for designs that are less tall. The benefit of wider and wider machines also shrinks with full automation, even if it doesn't fully go away

You can see there are already huge examples of this in Australia with sheep grazing under panels and it's just barely starting in New York state with a cornell pilot. In my opinion it's the future of electricity in agricultural areas.

Smaller scale market gardens could benefit. Many rely on more manual labor and smaller machines.

There are some small organic farms using a system of chained paper pots and frames to quickly fill them with soil and sow with seeds, then once they're sprouted you use a hand pulled machine that spreads the chain out while directly placing each plant into the soil automatically.

Depends on what the crop is. Broccoli I imagine, is manually cut. same with tomatoes.

CdTe panels are limited by availability of tellurium. Maybe we'll mine that in space one day; much of the Earth's Te was lost as volatile H2Te. The abundance of Te in carbonaceous chondrites is about 1000x that in the Earth's crust.

Given that it's about as abundant as platinum (which trades at ~$50000/kg), tellurium is pretty cheap right now (~120$/kg, about 10 times the price of copper).

Since it's an almost free byproduct of copper electrorefining (>1% concentration in copper anode slime, but low annual production of ~800 tons, limiting CdTe panel production to ~100GW/year short term [1]), I don't think that mining it in space is ever gonna pay off for terrestrial panel production, because if it was priced somewhat comparably to platinum group metals you could never ever justify any demand for it (panels would be much too expensive compared to alternatives, tellurium is already a relevant cost factor for them despite being cheap-ish) => and you'd obviously use all interplanetary mining/transport capability on platinum and its ilk instead.

[1]: https://www.pv-magazine.com/2026/02/10/global-cadmium-tellur...

Yeah. Probably it would be better to look at alternative terrestrial sources, like manganese nuggets (which are maybe 40 ppm Te).

The layer of CdTe on a thin film PV module is extremely thin, so at current prices the cost of Te is a very small fraction of the cost of the module.

On top of that, there are 53% more atoms in a kg of Tl than there are atoms in a kg of Pt!

Tellurium is Te. Tl is thallium.

Of course, thank you for pointing that out. The math still maths :)

There's the minor issue in that the technology to bring all that metal back home is also a weapon of mass destruction :-/

Kinetic orbital bombardment is utterly worthless from a military perspective.

People tend to have a completely inaccurate view on this because of bad popsci, out-of-context feasibility studies from the 1950s and fiction that just leans toward the "fantasy" on that.

The reasons for this is are very simple:

1) There is no "high ground". Being in orbit does not enable you to throw things "down" for free, thats simply not how orbital dynamics work. All the impact energy you have to pay for up front, and delta-v on some orbital object is almost inevitably more expensive than the equivalent amount of explosives on the ground.

2) Anything launched from beyond earth orbit would be unusably delayed. And telegraphed.

3) The concept does not have a single selling point from a military perspective; not really faster than an ICBM, penetration is limited by newtonian physics regardless of speed and more expensive than just delivering the equivalent amount of explosives (or nuclear payload) via missile.

edit: Yes an interplanetary transport system could be weaponized. But so could the explosives currently used in mining (~tens of millions of tons per year), no one cares.

If North Korea or Iran could hold the world hostage with a threat of a mass-extinction-level event, they absolutely would. Similar for many terrorists of various stripes. Are you sure the control systems of whatever company ends up trying to bring back mass from space will be sufficiently resilient to hacking? I'm not. So, I worry.

And we're not even talking about "orbital" bombardment. We're talking about a continuous stream of material at well above escape velocity, whose delta-V is already paid for. Simply redirecting a few pieces of this stream would not be more telegraphed than any other attack. By the way, are you sure the control systems of the mine owners are resilient to coercion of their executives by "legitimate" terrestrial governments? I'm not. None of your reasons are effective.

The energies are substantially more than mining explosives, with wildly different properties as far as threat detection and mitigation. To put it charitably, that's a quite silly comparison.

Edit: now that I'm thinking about it, maybe the best mitigatiom would be to extrude all the mined material into some other very high surface area shape that can't survive reentry, no matter the mass, but can survive being accelerated for the trip home. Maybe a big long truss, with the engine at one end. And then also limit the payload size.

> We're talking about a continuous stream of material at well above escape velocity, whose delta-V is already paid for.

I don't know what exact scenario you are talking about here.

Even a huge construct (1000 tons?) at escape velocity has less energy than the smallest of nuclear weapons (20kt), and a tiny fraction of the explosives used in mining right now (at least megaton TNT equivalent/year).

> By the way, are you sure the control systems of the mine owners are resilient to coercion of their executives by "legitimate" terrestrial governments? I'm not. None of your reasons are effective.

Are you just playing devils advocate here? There is few things that I'm less concerned about than mining explosives being confiscated and repurposed for some shady-government terror campaign.

> If North Korea or Iran could hold the world hostage with a threat of a mass-extinction-level event, they absolutely would. Similar for many terrorists of various stripes. Are you sure the control systems of whatever company ends up trying to bring back mass from space will be sufficiently resilient to hacking? I'm not. So, I worry.

North Korea has weapons of mass destruction already, and delivery vehicles for them. So what? Those destructive capabilities are already much greater than anything they could ever hope to gain from ursurping some space-mining operation within the next centuries.

Russia has even greater capabilities and plenty of imperialist desires to fulfill, but those nuclear threats did not seem to help them gain anything of consequence over the last decade, and not for lack of trying.

The thing is that any organization wealthy/powerful enough to realistically gain access to militarily relevant systems will typically also have enough to lose to disincentivize haphazard use. Rare exceptions like 9/11 demonstrate how much circumstance is required to get around this.

Moving 1000 tons of Te back to Earth, and moving maybe 10^14 tons to hit Earth, are rather different capabilities.

1000 tons of Te would only be a fraction of what's brought back by a realistic mining operation. Don't you also want all the platinum and palladium and gold hiding out there? Don't you want the iron for building space habitats? No, we'll bring back as much as we can manage, whether it's availability or transport logistics or fear of attacks that turns out to be the limiting factor.

1000 tons is how much Te is mined each year on Earth.

Global annual production of platinum is 180 tons.

How is that relevant to the weaponizability of space mining systems, the thing I was actually talking about?

It shows that the claim that space mining enables mass-extinction level events is nonsense. Space mining can involve 11 orders of magnitude less mass annually than the K/T mass extinction impact.

The bar for mass extinction is much, much lower than the K/T impactor. The bar for widespread human suffering and death is much, much lower again. (edit: the bar for general terrorism is much, much etc.) You and myrmidon keep trying to anchor the conversation around these strawman criteria and mechanisms (i.e. "orbital bombardment", as if that was the topic). I'm sure it's just motivated reasoning but god damn is it hard to distinguish from bad faith argument.

> The bar for mass extinction is much, much lower than the K/T impactor.

Clearly not, otherwise there would have been many more mass extinctions.

In any case, shifting that by a couple of orders of magnitude doesn't save the argument.

Many more mass extinctions, you say? https://en.wikipedia.org/wiki/List_of_extinction_events These are still just the highlights.

Meanwhile, consider what a relatively minor event caused https://en.wikipedia.org/wiki/Year_Without_a_Summer . I don't know the exact size needed for an equivalent meteor impact, but it's a lot smaller than the Chicxulub impactor and we still don't want to get anywhere close to it. Even something like the Chelyabinsk meteor, which injured over a thousand people, would be a half-decent terror weapon.

What’s your opinion on the US’s MAD nuclear strategy?

It's pretty bad. I hate it. I wish there was a better one but I'm pretty sure that ship has sailed. Let's try to do something smarter with space mining.

If it gets separated at the asteroid the mass brought back is small. Total world production of Te is about 1000 tons/year.

I imagine a time long long ago, early humans debating the proliferation of fire.

I'd love this for a home greenhouse... I live in an area where during the summer insolation is high enough that some combination of large amounts shading and airflow (wasting humidity) is needed... wavelength-selective shading seems like an interesting idea to start with, and energy recovery from it is a nice add-on.

For a larger greenhouse a mix of clear non solar and solar pv pannels optimised for different plants could be the way to go. The polycarbonate clear pannels are actualy cheap and likely strong enough that I am considering mounting solar pv directly to them. So: scratch building a greenhouse frame, that will support all the loads, and attaching the panels, and run the wires right through the polycarb, standard solar pannels, install@40" width and that works out to 3 per 12', 12 pannels for 40', for a neat eve to eve install.

The only real problem with this becoming common practice? The very first question and assumption of needing a solution.

>Vegetable farms and solar farms both need lots of sunlight and open space. But how do we divide our limited lands between these two priorities?

We are in no way limited by farmland space. Farmland utilization has been dropping since WWI thanks to the invention of artificial fertilizer, and even without artificial fertilizer at current population levels we would have never ran out of farmland although there would be a lot more of it. All across the midwest you will find tracks of land that use to be farmland, but is now either overgrown with trees, grass, or shrubs and completely unutilized for any human purposes. And our main limitation to growing even more food if we wanted a bunch extra for some reason would be fertilizer production/energy, not land space.

This is great science and knowledge, but I don't expect anything useful coming from it for farming on earth. There is no shortage of dirt that the sun shines on now or anytime soon, and no matter how efficient your panels, plants, or extra lights are, the sun is free and a greenhouse is way cheaper than anything else you could possibly build.

Sure, all the solar power for the US could come from Australia.

Meanwhile, when planning and streamlining infrastructure for cities and large urban centres some do look to guidelines such as minimising transportation (food into cities, refuse out, etc) and transmission line costs.

Food production has water, sunlight, fertiliser etc. requirements, energy generation (solar, wind, coal, oil, gas) similarly has geolocation (sunlight for solar, temperature differentials for wind, mine / port access for solid fuels, pipelines and tanks for gas) requirements.

Urban planners also look to stability of supplies and robustness of systems (if X fails, what do we fall back on).

These are the manner of things that can put dual use demands on various parts of the ring about large urban areas.

There are countless square miles of vacant land in the USA that are unsuitable for farming and ideal for solar. This might be useful in areas where vacant land is actually scarce.

The US is huge. The problem is efficiency of transmission. But maybe we just install 2x the solar to overcome that? When energy is so low cost we can afford to be a bit less efficient.

More storage too (transmit in time rather than in space).

A huge amount of corn goes into producing ethanol to burn as fuel in cars. We can safely take a small portion of agricultural land out of "food" production and replace it with photovoltaics and electrical production instead of using it to produce ethanol and produce productive stable returns for farmers instead of subsiding corn and fuel.

Yeah, and also you should eradicate sparrows. Each sparrows consumed several kilograms of grain per year, so by eradicating them you will need even less agricultural land.

That vacant land tends to be far away from electricity users. Not always - lots of desert around Las Vegas - but people historically like settling around arable land. Producing electricity close to where you need it is great, both because of transmission losses and because building more long-distance transmission lines is neither easy, cheap nor fast

I feel like starting with parking lots might be better than filling "empty" land though?

It really does seem like a no brainer. They should already be close to other infrastructure and they provide shade for parked cars which reduces the energy spent cooling the cars when people drive away. Even if you make very safe assumptions about the total area of parking lots in the US and their sun exposure, the amount of energy they could generate from solar panels on average rivals the current solar output.

Plenty of rooftop space for solar.

Yes, but not plenty of support or access to make it practical.

its _far_ cheaper to retrofit carparks than it is roofs. generally there is nothing under a carpark apart from tarmac. Unlike a roof which was designed for a specific weather loading (be it wind, rain or snow)

You also need to attach the panels to the roof, its generally simpler to bolt into tarmac compared to bonding to a weather proof seal.

Where i am in the eu, car parks are where its at. Apart from on dirty great field which is being filled with panels for some reason.

The better solution to this vacant land is to remove the regulatory and permitting burden that made it vacant in the first place.

Let the people build.

We should be increasing the amount of wilderness space in the world. Let the people build denser before building wider.

Wild, I did a science fair experiment on plant growth vs light color as a young kid! i had each plant in a different shade of upside down tumbler cup and compared the growth. N=1 for each cup, but I remember being surprised that the plants really didn’t seem to care when you filtered out certain shades.

I really wouldn't want anything containing cadmium near a farm field.

What could possibly go wrong?

Material Science Gameplay Loop

1. Development Miracle Substance

2. Try to replicate the properties without Cadmium, Mercury, Arsenic, and Lead

3. Figure out how to scale production

4. Congratulations you're selling the material, but 6 months ago another team had a break through, so the loop resets.

Man I’d buy and install these in a heartbeat. My suburban house has a couple of small areas that would be perfect for a greenhouse that produces electricity

I like the idea of hybridizing the solar infrastructure to work with advanced AG systems. I watched a recent tour of a modern strawberry farm, and I was surprised that they were using wheeled robots instead of overhead tracks.

https://www.youtube.com/watch?v=TumxO2glmPQ

I especially like how this could reduce the need for irrigation in dryer climates.

Literal children of the magenta.

Yes but it's sealed between panes of glass:

Image: https://www.cell.com/cms/10.1016/j.xcrp.2026.103555/asset/c8...

Paper: https://www.cell.com/cell-reports-physical-science/fulltext/...

Theory is always more interesting than practice, because theory never has to make money.

Remember spacex is a public company and you can short the company at any time if you believe what you're saying. Why not profit off it?

I think the question is, are these panels less expensive than taking normal panels, maybe with LEDs to help growth at night, and adding solar tracking to optimize solar generation, plant shading, and plant growth?

Answered in this thread:

https://news.ycombinator.com/item?id=50428018

It seems like it would only work out for shade loving crops in areas where net metering is an option.

Have the panels mostly cover the crops in the day time (improve yields) and export to the grid (reduce or eliminate electricity costs), then turn on LEDs for some portion of the night (improve yields) and import enough to offset your exports (use any excess you have from the day time).

In those situations, the additional cost could be zero or even a net benefit with some increase in crop yield.

Economics would suggest full spectrum panels on the outside + LED-lights on the right spectrum on the inside will always be more affordable than specialized panels. You still need lights with magenta panels to hit 18+hrs of light a day. Once the lights are already installed, specialized panels would be hard to justify a mark-up.

> Economics would suggest full spectrum panels on the outside + LED-lights on the right spectrum on the inside will always be more affordable than specialized panels.

Lookup the energy needs to grow plants, panels are like 25% efficient, you'd need to put most of it back into the LEDs to grow anything. Growing LEDs aren't your regular 5w home light bulbs, you need a lot of energy to grow plants.

This is the classic out of depth HN take

I was thinking this further through. What you write was indeed the next thought… and the reason we don’t grow in multistory factories is… cost! So sunlight is the OG for greenhouse growing. Cost of m2 free ground or glass do not matter when compared to building space, lights and energy.

This does lead me back to the idea that to cover greenhouses with translucent panels, you would need translucent panels to have undergone a price drop comparable only with regular panels. Which is unlikely. And then you have risks like hail risks that multiply when covering greenhouses with panels. Although that might be an upside, since greenhouses in NL are actively going towards break free glass which is pretty expensive. So perhaps there is a break free translucent solar panel upgrade route that could work out. (I am sceptical, but it is a nice idea indeed. Light is a spectrum and not all light is equal in photosyntesis.)