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[–] AlteredEgo@lemmy.ml -2 points 1 day ago (1 children)

A skyscraper with solar panels covering its southern face can produce a lot of vegetables. Sure, maybe carb-heavy vegetables still need to be done outdoors, but a balanced diet requires more than carbs.

You need the chemical energy to survive and that requires a lot of light to convert. That is the "critical path". Forget about vegetables, they are not important to solving the food problem.

You're so arrogant but fail to understand the basic engineering and math problems. This is a waste of time.

[–] wonderingwanderer@sopuli.xyz 2 points 1 day ago (1 children)

You act so smug, but you don't seem to realize that warehouse farming is already a thing. This isn't some personal utopian fantasy theory of mine, it's a thing that already exists and can be implemented at a larger scale to solve problems ranging from food deserts, malnutrition, transportation costs, winter spoilage, pests, water consumption, run-off, and habitat destruction due to the agricultural demands of feeding several billion people.

There are specific wavelengths of light that plants use to do photosynthesis. Those wavelengths can be isolated, and there are special LEDs designed specifically for this purpose. They're quite efficient. Or you can use fluorescent lights, albeit they're less efficient than LEDs. You don't need the full spectrum and intensity of direct sunlight, and in fact that can be harmful in hot/dry climates or during droughts, especially as global warming accelerates. Warehouse agriculture has much higher yields than outdoor farming because you can control the climate perfectly while keeping out pests and diseases.

As for fertilizers and compost, they can be used in warehouse agriculture with more efficiency and with less environmental impact than in conventional farm fields. So your chemical energy point is moot.

You talk to me of the engineering and math problems, but clearly you're the one who fails to understand them.

Don't you know how much environmental destruction is currently due to clearing more space for agriculture? And you think that won't get worse as the world population nearly doubles in size, unless we start doing multi-story warehouse farming to feed major population centers?

[–] AlteredEgo@lemmy.ml 1 points 18 hours ago* (last edited 18 hours ago) (1 children)

You act so smug, but you don’t seem to realize that warehouse farming is already a thing.

No, you're just wrong. It is a thing for profitable vegetables or leafy greens or strawberries, but not for producing calories. It will not feed 15 billion people.

With something like 3 kWh of solar irradiance per day per m² you get a pretty abysmal <5% efficiency for producing food calories compared to the 20% efficiency of solar panels. So you quintuple the amount of land you need with solar panels, maybe a little less with higher efficiency indoors. Less with kite power. Again less with fusion power. It's still alot of embedded energy.

I made this table to see how many square meters actually feeds a person, very rough numbers but all I've found. It's less than 250m² in moderate climates to produce 2.2 kcal food. If we stop eating meat and "luxury foods" from around the world we drastically reduce energy costs and reduce land use so we can rewild like 90% of the current arable land.

Conclusion: There is no shortage of land to feed 15 billion people.

And why grow your vegetables and fruits and strawberries far off, or in a bunker, when you can build a million local greenhouses in your community that could additionally serve as food gardens or parks in colder weather?

Kcal / acre / year Kcal / m² / day kWh / m² / day Efficiency from 3kWh sunlight Land m² / person Protein %
Potato 15,000,000 10.0 0.0116 0.39% 219 9.50%
Potato Ireland 2017 FAO 14,163,653 9.5 0.0110 0.37% 232 9.50%
Potato USA 2019 FAO 15,858,541 10.6 0.0123 0.41% 207 9.50%
Potato Oregon 2019 USDA 20,940,336 14.0 0.0162 0.54% 157 9.50%
Potato Simplify Gardening 18,036,045 12.1 0.0140 0.47% 182 9.50%
Sweet potato 3x hypothetical 93,000,000 62.2 0.0721 2.40% 35 7.00%
Rice 11,000,000 7.4 0.0085 0.28% 299 8.10%
Rice USA 2018 FAO 14,655,018 9.8 0.0114 0.38% 224 8.10%
Soybeans 6,271,628 4.2 0.0049 0.16% 525 36.40%
Chickpeas 6,013,636 4.0 0.0047 0.16% 547 20.50%
Chickpeas China FAO 8,329,810 5.6 0.0065 0.22% 395 20.50%
Chickpeas Israel 2017 FAO 9,494,407 6.3 0.0074 0.25% 347 20.50%
Chickpeas Turkey 1,440,259 1.0 0.0011 0.04% 2284 20.50%
Pinto Beans 23.70%
Corn 15,000,000 10.0 0.0116 0.39% 219 10.40%
Corn Jordan 2018 FAO 58,323,364 39.0 0.0452 1.51% 56 10.40%
Corn USA 2018 FAO 18,413,214 12.3 0.0143 0.48% 179 10.40%
Wheat 4,000,000 2.7 0.0031 0.10% 822 14.50%
Wheat Ireland 2017 15,670,035 10.5 0.0122 0.41% 210 14.50%
Oats 175 bu/acre 1,125,399 0.8 0.0009 0.03% 2923 17.00%
Chlorella 86,045,604 57.5 0.0667 2.22% 38 58.40%
Solein solarfoods.fi 193,371,336 129.3 0.1500 5.00% 17 65.00%
Microalgae 5% hypothetical 193,371,336 129.3 0.1500 5.00% 17 57.47%

PS: Solein claims 5% by splitting water into hydrogen using solar power and then using hydrogen to feed single celled organisms. If we ever find a way to split water into hydrogen directly using fusion we'd be set. But until then it's not more efficient than other food algae (also about 5% efficient, which is already great for mostly protein).

[–] wonderingwanderer@sopuli.xyz 0 points 13 hours ago (1 children)

If you think leafy greens are only good for making a profit, then you're the one who's wrong. Nutrition is about more than just calories. Someone who doesn't get enough calories gets malnourished, someone who doesn't get enough nutrients gets malnutrition. It's two different things. Vegetables are necessary and you can't just write them off, much as you seem to want to.

Also, a vertical warehouse operation has multiple stories and can have panels mounted all up the southern face. You don't need to have an entirely horizontal solar farm, so no it doesn't quintuple the land you need.

And yes, eliminating meat from the common diet can help to rewild arable land, but that's a completely separate conversation and not an argument against warehouse agriculture.

Saying there's no shortage of land to feed 15 billion people is irresponsible though, because without any major changes to the way things are done, feeding 15 billion people would absolutely result in more habitat destruction.

And why grow your vegetables and fruits and strawberries far off, or in a bunker, when you can build a million local greenhouses in your community that could additionally serve as food gardens or parks in colder weather?

You don't seem to understand the issue at all. Building a million "local" greenhouses takes up space. Each greenhouse has a footprint. The millionth one over won't be very "local."

The point of warehouse farming (rather, one of the points), is that it can be done in urban centers where there's no space for greenhouses. It's literally a solution for food deserts and transport costs associated with the majority of food being produced in rural areas. Warehouse agriculture brings food production closer to population centers. I've already pointed that out multiple times and you just seem to ignore it.

If we ever find a way to split water into hydrogen directly using fusion we'd be set.

That's not what fusion is at all. I've already corrected you on this, which you also ignored.

Nuclear fusion is when you take two atoms and fuse them into a different kind of atom. The simplest form is making one helium atom from two hydrogen isotopes.

It has nothing to do with "splitting water into hydrogen." We can already do that. It's called electrolysis. Plants need more than just hydrogen though, so I'm not sure what your point is there.

[–] AlteredEgo@lemmy.ml 1 points 2 hours ago (1 children)

That’s not what fusion is at all.

You didn't correct me, you misunderstood me. See https://en.wikipedia.org/wiki/Radiolysis#Hydrogen_production

Solein (single celled microorganism) can use hydrogen and oxygen as fuel to produce carbo hydrates and protein. Needs co2 and some minerals too of course. If you could genetically engineer it to taste good and look less like puke, it would be perfect.

[–] wonderingwanderer@sopuli.xyz 1 points 2 hours ago* (last edited 2 hours ago)

Okay, good luck with that. You go feed your people hydroslop and I'll build warehouse farms and we'll see whose people have better nutrition.

Also, the radiolysis page says nothing about fusion. The nuclear waste it talks about repurposing is from fission reactors. Keep up.