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Agriphotovoltaics is largely a solution for a non-existing problem. It is always brought forward as an argument when the perceived landuse issue of solar is br

by hannob 2y ago

Agriphotovoltaics is largely a solution for a non-existing problem. It is always brought forward as an argument when the perceived landuse issue of solar is brought forward. But if you do any serious analysis, the landuse impact of even utility scale solar is so neglegible that it's not an issue to worry about. If you want to talk about landuse impacts of renewable energy, there's really only one issue to focus on: bioenergy crops. It can be as bad as 30 times less space efficient than generating the same energy with solar photovoltaics. Talk about using the same space to make food and bioenergy. Use agricultural land for food, and utilize the residuals as good as possible. Stop making biofuels out of food. And treat the space needed for utility-scale solar as what it is: tiny. (P.S.: If people can make agriphotovoltaics work, I have no issue with that. Great. Even tiny impacts should be reduced if possible. But I have an issue with the way this is discussed, because it makes up a problem with photovoltaics that largely doesn't exist.)

daveguy 2y ago
I think this implementation and purpose is slightly different. The climate they are testing in is East Africa. One harvesting is the photovoltaics for energy. But the second harvesting is for food crops. The partial shade provided by the PV panels allows the plants to lose less water from evaporation and protect against overexposure to sun so that food crops like beans and corn can provide higher yield in a normally difficult climate zone. I agree harvesting the sun as PV + biofuels is a step down, but PV + food crops in a difficult climate zone is a step up.
0_____0 2y ago
Great points Some (very rough) numbers to give scale here: Corn in the US covered ~90 million acres in 2024. Something like 40% of that gets turned into ethanol IIRC. Based on solar capacity figures around ~200GW, the surface area of the PV panels themselves (not the installation) are about 250-300k acres. Both solar and bio-ethanol render an energy output on the order of 250-350TWh/year. Broadly similar levels of energy, but using a tiny fraction of the land area and chemicals and industrial pollution for the former.
- shawn-butler 2y ago
  https://afdc.energy.gov/data/10339 https://afdc.energy.gov/data/10339
nanomonkey 2y ago
Don't throw biofuels out, there are plenty of fuels you can make from the parts of plants that we do not eat. Corn stover, walnut shells, bigasse, olive pits, etc. are all unused components that can be converted into fuel sources through gasification, anaerobic digestion, fermentation, etc. into usable fuel. Many times it's better than letting these leftovers rot in the fields and release methane into the atmosphere. Honestly, I'd like to see some of the excess solar energy put into up converting such waste streams into storable fuels that can be used as denser alternatives to batteries when needed (winter heating, air travel, etc.).
- gamblor956 2y ago
  Also, biofuels have >10x the energy per unit of mass compared compared to even the best batteries in the lab (and some sources put that at closer to 100x). There are a lot of use cases for biofuels (as a replacement to petroleum) that batteries can't come close to handling. Converting the waste stream from agrivoltaics into biofuels appears to be the best option: reduced land for "energy" crops, increased output for food crops, and biofuel to replace petroleum.
  - corysama 2y ago
    Converting waste to fuel is great. Meanwhile, I’m pretty excited about this project to make it cheap and easy to convert solar power to liquid fuel. Starting with carbon-neutral natural gas. https://youtu.be/cRg1ZVwttNU?si=JWK5ZUdlNWooNYtt https://youtu.be/cRg1ZVwttNU?si=JWK5ZUdlNWooNYtt
  - 542354234235 2y ago
    I feel like hydrogen is the answer to fossil fuels, not biofuels. Battery electric vehicles (BEV) are great for personal vehicles. But for heavy transport, batteries just don’t work. They are too heavy and can’t be “refueled” quickly for continuous operations. We are already having issues with having too much solar power and not enough demand. We could be load shedding that by using it to create hydrogen. We have gas stations everywhere because individuals need that kind of convenience to operate comfortably. BEVs have the same infrastructure in that every outlet is a charging station. While the barrier to entry for hydrogen is too high for personal vehicles, the logistic hub nature of heavy transport would be much easier to convert, using hydrogen storage/filling stations at strategic location to support hydrogen powered semi-trucks, local delivery trucks, busses, etc.
salynchnew 2y ago
Correct arguments all around re: utility scale solar, but the incentives for an individual farmer to immediately adopt are huge: local generation makes power cheap, shading makes water use more efficient, etc. Obviously there is a capital cost for the system and costs for maintenance, etc., but given the trend of increasing global energy costs and the resulting burden on households (https://www.nature.com/articles/s41560-023-01209-8 https://www.nature.com/articles/s41560-023-01209-8), it seems like a very nice idea.
rendaw 2y ago
The article's arguments don't revolve around landuse, and in fact the article doesn't discuss landuse at all.
- explodes 2y ago
  In rural parts of Colorado, I have seen large signs on farm building protesting the use of agriculture land for solar.
TZubiri 2y ago
Who complains about the land use of solar? Obviously not a bottleneck? There's millions of desert acres.
NathanKP 2y ago
The main advantage that I see in agrivoltaics is for the purpose of density. If you can get both power and food production in a more dense footprint, located closer to a population center, then that will be much more efficient for purposes of transportation. Both electricity transmission and food transportation get worse across larger distances.
- ianburrell 2y ago
  Power transmission is really efficient, HVDC is around 3% per 1000km, AC is around 6%. It is more efficient to put solar panels in sunny areas and transmit across country than have less efficient local ones. Oregon where I live is bad for solar with lots of rain, it is better to put panels in California desert and bring up here. Food is similar where transportation doesn't matter much. Staple foods can be shipped by train, barge, and ship which reduces the cost. Some places are better at growing food. The canonical example is that New Zealand is so much better in growing sheep that more efficient to ship lamb by air. Growing local only makes sense for vegetables that need to be fresh or don't transport well.

by hannob 2y ago

daveguy 2y ago

I think this implementation and purpose is slightly different. The climate they are testing in is East Africa. One harvesting is the photovoltaics for energy. But the second harvesting is for food crops. The partial shade provided by the PV panels allows the plants to lose less water from evaporation and protect against overexposure to sun so that food crops like beans and corn can provide higher yield in a normally difficult climate zone. I agree harvesting the sun as PV + biofuels is a step down, but PV + food crops in a difficult climate zone is a step up.

0_____0 2y ago

Great points Some (very rough) numbers to give scale here: Corn in the US covered ~90 million acres in 2024. Something like 40% of that gets turned into ethanol IIRC. Based on solar capacity figures around ~200GW, the surface area of the PV panels themselves (not the installation) are about 250-300k acres. Both solar and bio-ethanol render an energy output on the order of 250-350TWh/year. Broadly similar levels of energy, but using a tiny fraction of the land area and chemicals and industrial pollution for the former.

shawn-butler 2y ago
https://afdc.energy.gov/data/10339 https://afdc.energy.gov/data/10339

nanomonkey 2y ago

Don't throw biofuels out, there are plenty of fuels you can make from the parts of plants that we do not eat. Corn stover, walnut shells, bigasse, olive pits, etc. are all unused components that can be converted into fuel sources through gasification, anaerobic digestion, fermentation, etc. into usable fuel. Many times it's better than letting these leftovers rot in the fields and release methane into the atmosphere. Honestly, I'd like to see some of the excess solar energy put into up converting such waste streams into storable fuels that can be used as denser alternatives to batteries when needed (winter heating, air travel, etc.).

gamblor956 2y ago
Also, biofuels have >10x the energy per unit of mass compared compared to even the best batteries in the lab (and some sources put that at closer to 100x). There are a lot of use cases for biofuels (as a replacement to petroleum) that batteries can't come close to handling. Converting the waste stream from agrivoltaics into biofuels appears to be the best option: reduced land for "energy" crops, increased output for food crops, and biofuel to replace petroleum.
- corysama 2y ago
  Converting waste to fuel is great. Meanwhile, I’m pretty excited about this project to make it cheap and easy to convert solar power to liquid fuel. Starting with carbon-neutral natural gas. https://youtu.be/cRg1ZVwttNU?si=JWK5ZUdlNWooNYtt https://youtu.be/cRg1ZVwttNU?si=JWK5ZUdlNWooNYtt
- 542354234235 2y ago
  I feel like hydrogen is the answer to fossil fuels, not biofuels. Battery electric vehicles (BEV) are great for personal vehicles. But for heavy transport, batteries just don’t work. They are too heavy and can’t be “refueled” quickly for continuous operations. We are already having issues with having too much solar power and not enough demand. We could be load shedding that by using it to create hydrogen. We have gas stations everywhere because individuals need that kind of convenience to operate comfortably. BEVs have the same infrastructure in that every outlet is a charging station. While the barrier to entry for hydrogen is too high for personal vehicles, the logistic hub nature of heavy transport would be much easier to convert, using hydrogen storage/filling stations at strategic location to support hydrogen powered semi-trucks, local delivery trucks, busses, etc.

salynchnew 2y ago

Correct arguments all around re: utility scale solar, but the incentives for an individual farmer to immediately adopt are huge: local generation makes power cheap, shading makes water use more efficient, etc. Obviously there is a capital cost for the system and costs for maintenance, etc., but given the trend of increasing global energy costs and the resulting burden on households (https://www.nature.com/articles/s41560-023-01209-8 https://www.nature.com/articles/s41560-023-01209-8), it seems like a very nice idea.

rendaw 2y ago

The article's arguments don't revolve around landuse, and in fact the article doesn't discuss landuse at all.

explodes 2y ago
In rural parts of Colorado, I have seen large signs on farm building protesting the use of agriculture land for solar.

TZubiri 2y ago

Who complains about the land use of solar? Obviously not a bottleneck? There's millions of desert acres.

NathanKP 2y ago

The main advantage that I see in agrivoltaics is for the purpose of density. If you can get both power and food production in a more dense footprint, located closer to a population center, then that will be much more efficient for purposes of transportation. Both electricity transmission and food transportation get worse across larger distances.

ianburrell 2y ago
Power transmission is really efficient, HVDC is around 3% per 1000km, AC is around 6%. It is more efficient to put solar panels in sunny areas and transmit across country than have less efficient local ones. Oregon where I live is bad for solar with lots of rain, it is better to put panels in California desert and bring up here. Food is similar where transportation doesn't matter much. Staple foods can be shipped by train, barge, and ship which reduces the cost. Some places are better at growing food. The canonical example is that New Zealand is so much better in growing sheep that more efficient to ship lamb by air. Growing local only makes sense for vegetables that need to be fresh or don't transport well.