[HN Gopher] Harvest the sun twice: Agrivoltaics promises sustain...
___________________________________________________________________
Harvest the sun twice: Agrivoltaics promises sustainable food,
energy and water
Author : gnabgib
Score : 167 points
Date : 2025-02-27 16:56 UTC (4 days ago)
(HTM) web link (www.sheffield.ac.uk)
(TXT) w3m dump (www.sheffield.ac.uk)
| rompic wrote:
| Just read an article about one of these in the local newspaper.
|
| They currently have some challenges with bureaucracy, at least in
| Austria:
|
| Given that it is an industrial facility it has to be secured from
| unauthorized access, but as it is a field, it has to be
| accessable to small animals. So now it is fenced with barbed wire
| on the top but it's open at the bottom.
| tfourb wrote:
| Not the case in Germany. Photovoltaic installations on
| agricultural plots are routine, in certain cases (I.e. the plot
| is next to a motorway) you don't even need a planning/building
| permit, as long as the installation conforms to established
| building practices. Agrivoltaics is still a niche practice, but
| not because of bureaucratic concerns.
| ashoeafoot wrote:
| My brothers farm had an offer by a similar startup with different
| dimensions but basically the same idea.
|
| Had problems though. First was moving parts. You can not expect a
| system to last outside with any in them. Budget for the whole
| affair is tight, large repairs undo the whole endeavour .
|
| Second is crops riping at different speeds below.
|
| Finally practicality of the frame for farming machines . Meaning
| the dimensions need to adapt to pre-existing machines. And
| ideally remain upright even if one post gets hit.
|
| Finally honesty regarding erosion ..corn is one of the more
| erosion prone crops and then having water dumped on specific
| areas concentrated creates channels fast. So the idea does not
| work with no crops or erosion crops in rainy areas. There is a
| reason there is grass below most solar fields.
|
| One good aspect they didn't push is that this is ideal for
| electro farming. We have hyper effective electric moisture traps
| now and electro nitrogen fixing- combine that and this can remove
| one need for driving trucks through.
|
| In all other aspects i see this limited to orchards.
| otherme123 wrote:
| > In all other aspects i see this limited to orchards.
|
| This study is for a very specific region: East Africa (Kenia
| and Tanzania). Their main problems are too much evaporation, no
| energy sources, no other sources of food.
|
| I don't see how a solution that might work for a good share of
| humanity (Africa is huge: Kenya and Tanzania alone have 150
| million people) gets dismissed as "limited to orchards" because
| it can't be used for industrial scale corn crops in my country.
| rob74 wrote:
| Well, unfortunately "Africa" is only mentioned in the
| article's title (which got cut to fit into HN's character
| limit) and not repeated in the article itself.
|
| But I can understand the concern: most agriculture (not only
| corn) is highly mechanized pretty much everywhere in the
| world except the poorest countries, so this would be limited
| to the crops that can't be mechanized.
| otherme123 wrote:
| Or this can be adapted to mechanized crops where it makes
| sense. Greenhouses where small fragile minihouses of 4x3
| meters, made of wood and glass 100 years ago, used only in
| countries with harsh winters. Nobody in their right mind
| would use a tractor to work on them. Today they can be seen
| from the space and are mechanized... where it makes sense
| to do it. They turned a desert into a huge production of
| fresh vegetables:
| https://www.amusingplanet.com/2013/08/the-greenhouses-of-
| alm... .
|
| Agrivoltaics could be something or nothing. But don't
| dismiss it because it _today_ isn 't already perfect for
| everything. Ten years ago the cost of the panels alone
| would make this projects 100% infeasible.
| rob74 wrote:
| Those plastic-foil greenhouses spreading like cancer
| across the landscape in Spain should be shown (especially
| up close, where you can better see the dirty tattered
| foil and the waste they produce) to people who think
| solar panels or wind turbines are eyesores. I would
| definitely support replacing those cheapo greenhouses
| with something more permanent involving solar panels!
| ashoeafoot wrote:
| I wouldn't sum up the challenges if i would be completely
| dismissive , i think the potential is there, especially
| when it comes to in situ fertilizer nitrogenfixing and
| electro moisture harvesting (the breakthroughs there are
| insane, from peltier 50ml to condensator 500 ml
| recently). This is not a attack on the idea, just a lets
| strengthen this to solve alot of problems .
| Lutger wrote:
| Vertical bifacial agrivoltaics system are a promising setup
| that addresses some of your concerns. Most importantly,
| tractors can easily pass through them.
|
| Another good setup is to combine it while grazing sheep.
| lostlogin wrote:
| A problem with sheep is that they aren't worth anything. Here
| is New Zealand we have replaced nearly all of them with cows.
| Much improved profits but destruction of the waterways. We
| call that a win.
| the_sleaze_ wrote:
| Hot take: compress them all cheek to cheek in a warehouse,
| feed them corn and capture the methane they produce. Cover
| the roof in solar.
|
| Call that an even bigger win...
| tomrod wrote:
| Or hayfields.
| pfdietz wrote:
| Here in the US, a field of hay might gross $500/acre/year. A
| PV field selling power at $0.02/kWh would gross 50x that.
| You'd optimize such a setup for PV, not for combined PV +
| hay.
| tomrod wrote:
| Aye, the question I answered wasn't focused on optimal
| layout, but potentially compatible crops.
| cmrdporcupine wrote:
| Definitely doesn't seem appropriate for cash crops harvested by
| combine harvester.
|
| Most orchards and vineyards in temperate climates are
| attempting to maximize solar exposure, so would compete for
| space with the panels -- and also have their own trellising
| systems and so I struggle to see a fit there, too.
|
| But I can definitely see the use cases for two places.
|
| Grazing land for some ruminants, especially in hot dry
| climates. Provide shelter for animals, and shade for grasses.
|
| Vegetables, market garden or even large scale. (e.g. my
| neighbour grows something like 20 acres of cauliflower and it's
| all planted and picked by hand.) Many market gardens are using
| walk-behind / two-wheel tractors (BCS, etc.) which are far more
| agile and could easily handle moving around panels.
|
| Spill-off / erosion can be dealt with through building swales.
| eldaisfish wrote:
| that's ok. Not every solution must work for all situations.
|
| the point here is that agrivoltaics tends to work well,
| especially in certain conditions. In central Africa, those
| conditions are reducing evaporation and providing shade to
| certain plants.
|
| In north america, those conditions are often sheep grazing,
| as is common in New York and Ontario.
| cmrdporcupine wrote:
| Aside: There seems to be an uptick in sheep rearing in my
| area (southern Ontario, near Hamilton) all the sudden. In
| the last year, I've seen 3 farms local to me put up fencing
| to start grazing them. Which is interesting because it's
| actually very difficult to find Ontario lamb in the butcher
| shop, and it's not a very popular meat overall, so I'm
| wondering where the source of the demand is. The majority
| of the lamb in the local grocery stores is either frozen
| prepacked from New Zealand, or from Sun Gold foods in
| Alberta. But I find local lamb from this area tastes much
| better (less gamey), must be something about the grass vs
| whatever forage they're giving them in Alberta.
|
| My two border collies would love it if I raised sheep. But
| my quasi-vegetarian wife could never tolerate raising them
| for meat.. and dairy and wool make no $$ sense.
| eldaisfish wrote:
| My guess - immigrants are the source of demand. South
| Asian and Middle Eastern immigrants eat lots of lamb. I
| live in the area and buy my lamb from a local farm.
| You're correct, it is not the most popular commercial
| meat.
| cmrdporcupine wrote:
| Yeah that's my assumption to.
|
| The little Halal butcher around the corner from my office
| in Oakville consistently stocks fresh lamb. Doesn't see
| if it's Canadian or not though.
|
| Many years ago we used to buy, once a year, a whole
| butchered lamb raised on a friend's farm down in Niagara.
| lurk2 wrote:
| > One good aspect they didn't push is that this is ideal for
| electro farming. We have hyper effective electric moisture
| traps now and electro nitrogen fixing- combine that and this
| can remove one need for driving trucks through.
|
| Could you tell us more about this? I remember seeing a user
| comment a few years ago discussing the prospect of dumping
| excess electricity into nitrogen production but I had assumed
| it wasn't feasible. Does this technology really exist?
| ashoeafoot wrote:
| https://advanced.onlinelibrary.wiley.com/doi/full/10.1002/ad.
| ..
|
| There is one experiment in kenia
| ashoeafoot wrote:
| https://www.youtube.com/watch?v=G2brxBRnRH4
|
| high voltage moisture trap
| usrusr wrote:
| > Finally practicality of the frame for farming machines .
| Meaning the dimensions need to adapt to pre-existing machines.
| And ideally remain upright even if one post gets hit.
|
| I believe that the end-game for agrivoltaics must be a reversal
| of that relationship: not the panel scaffolding adapting to
| farming machinery, but farming machinery and panel scaffolding
| becoming one, the scaffolding doubling as rails for overhead
| machinery. The status quo in farming is that a lot of fertile
| ground is wasted on machinery tracks. Machinery is either
| narrow-wheeled and ruining the soil in the track through
| compression, or the wheels are very wide (for weight
| distribution) to cause less harm per square inch, but harming
| proportionally more.
|
| When you have scaffolding, scaffolding that is strong enough to
| survive a storm or two, it will also be strong enough to carry
| machinery. Not the machinery you'd attach to a 600 HP tractor,
| but the entire incentive situation for machinery size is based
| on the amount of harvest lost to machinery tracks and that
| would be completely solved through scaffolding-based machinery.
| And the issue of machinery tracks (and ground compaction) only
| gets worse when you start considering decarbonization:
| batteries are heavy, and a grid connect right above your field
| would be just what you'd not even dare dreaming of.
| andy_ppp wrote:
| Yes you could easily combine solar panels and poly-tunnels for
| example. We have the potential over the next few years to make
| everything work so well but instead the US seems to be cutting
| cyber funding.
| ZeroGravitas wrote:
| I've read an article with vertical bifacial panels between long
| hemispherical greenhouses to catch reflections.
| grumpy-de-sre wrote:
| Photovoltaic "fences" are one of those bizarre ideas that
| might actually make sense.
| postepowanieadm wrote:
| There's a simpler way: you may burn oats and generate heat/power
| without relying on problematic solar panels. It's already quite
| common.
| pinkmuffinere wrote:
| Sorry, how is this better? The whole path of [grow oats ->
| maintain steam power plant -> ship and burn oats] seems much
| harder to me than using solar cells?
| looofooo0 wrote:
| No, EROEI for this is just bad if not negative. Also you do not
| produce any food.
| ZeroGravitas wrote:
| What's problematic about solar panels?
|
| There's a reasonable amount of waste biomass generated by farms
| that can be used in various ways without growing it
| specifically for that use.
| pjc50 wrote:
| People just like using "problematic" as a content-free slur
| that's acceptable in "progressive" circles that bypasses
| critical thinking.
| postepowanieadm wrote:
| Mainly recycling.
| ZeroGravitas wrote:
| Even if you couldn't recycle them, they'd be a much better
| solution than what they replace.
|
| The fact that you can recycle them just makes them even
| better.
| dukeyukey wrote:
| And the problem with that? Seems we can reasonably easily
| recycle the vast majority of solar panels, no differently
| to any other electronic good.
| eliaspro wrote:
| Comparing the landuse efficiency of corn-based biomass vs PV is
| about 60-75x.
|
| It just doesn't make any sense at all to use crops for energy
| production.
| pjc50 wrote:
| The only case where it might be viable is burning crop
| _waste_ ; stems of grain and maize, for example. The UK runs
| Drax on (imported! in oil burning ships!) sawmill waste, but
| that's greenwashing to me.
| eliaspro wrote:
| It definitely is. Besides that, Drax doesn't only run on
| waste products (that's what they'd like to make us
| believe), they mostly run on freshly logged timber.
|
| Most of it, imported from the US:
| https://www.biofuelwatch.org.uk/wp-content/uploads/Drax-
| brie...
|
| And even if it only was waste that's burned, it's IMHO
| incredibly stupid. We should be happy about every single
| gram of CO2 that's stored somewhere and use this "waste"
| for building insulation, paper production, soil
| revitalization or simply bury it.
|
| Burning simply shouldn't happen when we have way better,
| cheaper, more efficient, more environmentally friendly
| methods of producing heat and electricity.
| pfdietz wrote:
| In a post-fossil fuel age, that crop waste will be used as
| a carbonaceous feedstock for things like jet fuel and what
| are now petrochemicals. Burning it for power will be
| uneconomical.
| usrusr wrote:
| Unless you start considering carbon capture: if some direct
| carbon capture folly exists and you replace that folly with
| capturing the output of some crops-to-energy setup, then that
| would surely be a massive improvement over the carbon capture
| it replaced.
| rcxdude wrote:
| Growing crops for fuel is so absolutely ridiculously
| inefficient it's amazing anyone does it at all (It's usually
| not even energy-positive: the only way it makes sense is if you
| want to make sure you have excess food production and have
| _something_ you can do with the waste).
| KaiserPro wrote:
| Oats don't like hot dry areas, such as kenya in summer/dry
| season.
|
| plus, burning oats is really fucking expensive, the chaff is a
| reasonable feed, and the straw is good bedding/binder for
| building stuff.
|
| Burning for power is really a poor use, especially as it needs
| compressing into bricks first. Plus you only get a tiny bit of
| energy once a year, compared to ~1kwhr per panel per day.
| (depends on panel size and positioning etc etc )
| thowawatp302 wrote:
| What does "problematic" even mean here?
| metalman wrote:
| so called agrivoltaics will have certain very limited
| applications, and putting pv panels on the many very large
| agricultural buildings roofs, is much easier to integrate. A big
| risk with "agrivoltaics" is that they will in fact destroy the
| agricultural potential of land and then become the only source of
| income for the "farmers" , therby converting protected
| agricultural land, into purely industrial uses. Putting solar pv
| over canals is a better option, it reduces evaporation, while
| providing a cooler operating enviroment for the panels, in places
| that have no real constraints with developing them further.Also
| resevoirs can benifit/help in the same way with floating solar
| pv.
| KaiserPro wrote:
| > putting pv panels on the many very large agricultural
| buildings roofs, is much easier to integrate
|
| for industrial farming yes. This study is aimed at subsistence
| farmers in africa. ones that don't have much mechanisation.
|
| > will in fact destroy the agricultural potential of land
|
| Given that this study highlights the water conservation
| features of agrivoltaics, I'd say it has a greater chance of
| stopping salinisation of agricultural land from over
| irrigation.
|
| > Also resevoirs can benifit/help in the same way with floating
| solar pv.
|
| again, this is aimed at african farmers with limited
| infrastructure. this would be the stepping stone to getting
| cheap electricity
| grumpy-de-sre wrote:
| I really don't get the hype around Agrivoltaics at all. It all
| kind of pivots of the idea that land for Photovoltaics is scarce.
| Maybe it is in the UK but in the vast majority of the world this
| is a non sequitur.
|
| Cover the crop in shade cloth, and mount the panels on the ground
| / roof structures nearby. No need to over complicate things.
| aa-jv wrote:
| Do you have your own personal garden?
|
| I'm excited about it because its a combination of many things I
| truly enjoy doing and get a lot of pleasure from - harvesting
| energy, growing food, seeing life in equilibrium.
|
| The integrated growth-stands with full-spectrum solar -> plant
| -> fish -> soil process is really, really appealing. Healthier
| food, energy harvested in neat ways. If I can get carrots and
| radishes and salads from the same device that charges my cell
| phone in the next year or so, I'll be a happier human for sure.
| grumpy-de-sre wrote:
| > Do you have your own personal garden?
|
| Yes, every season I grow ~20kg of vegetables on a 15m^2
| balcony (tomatoes, cucumbers, peppers, celery, various
| herbs). They are grown vertically on a trellis system, using
| 11 liter hydroponic "bato" buckets and recycled/reused
| perlite (sterilized). Nothing fancy.
|
| The main energy input is the chemical fertilizer. Electricity
| to run pumps/valves etc is very minimal and probably amounts
| to 5-6 KWh over the season. I use synthetic fertilizers but
| avoid insecticides/fungicides, instead opting to use
| biocontrols (shout out to Koppert!
| https://www.youtube.com/watch?v=AFPkAQUfYvo).
|
| The future of agriculture (excluding cereal crops, which I
| dream might be replaced by synthetic starches one day)
| probably looks something similar to:
| https://www.youtube.com/watch?v=a_pR_HihCVo
| barrenko wrote:
| Now this is solarpunk.
| closewith wrote:
| > Maybe it is in the UK but in the vast majority of the world
| this is a non sequitur.
|
| Land near energy demand is scarce almost everywhere. This kind
| of local generation is ideal and both reduces transmission
| losses and makes the grid/society more resilient.
| grumpy-de-sre wrote:
| Rooftop photovoltaic can (and will) cover local needs. Bigger
| issue is local energy storage (eg. community batteries).
| closewith wrote:
| This is absurd. There's no limit to energy needs - they
| only grow.
| IndrekR wrote:
| Sure there are reasonable limits. Where, is another
| matter. For example, I can not imagine a reasonable use-
| case for 1MW power-line per single apartment.
| detourdog wrote:
| I was required to wire each unit with 150kW panel. The
| original 1931 service was 240 x 200 Amps which I upgraded
| to 240 x 800 Amps in 2018.
|
| I posted the best image I could of the original 1931
| schematic which has 9 circuits for 5,000 sqft school.
|
| It's the first image in this slide show.
|
| https://www.icloud.com/sharedalbum/#B2dGIcgc2GugpW3
| detourdog wrote:
| I'm not sure that holds true in a local sense. I have an
| all electric 8 unit apartment building. I have been
| tracking the electric usage and it is currently growing
| but only because of the addition of 2 EVs. I believe the
| the usage of actual electricity for the building to level
| off after EVs become the norm. I expect my electric usage
| to drop after adding a solar thermal collector to replace
| a portion of the electricity used for heating.
| closewith wrote:
| > I expect my electric usage to drop after adding a solar
| thermal collector to replace a portion of the electricity
| used for heating.
|
| Well, that's just harvesting more solar energy, not
| reducing your energy needs.
| detourdog wrote:
| True. Although it is self-sustaining and doesn't require
| outside production. I also distinguished between electric
| usage and thermal collection to satisfy overall energy
| needs.
|
| I guess I'm trying to point out that on an individual
| level power usage may have a maximum. This might not hold
| true for commercial ambitions.
| closewith wrote:
| I just don't agree. The energy we use today would be seen
| as absurd even 100 years ago, as will our energy use in
| the future.
| detourdog wrote:
| I see the difference between the USA's electric usage
| today and 100 years ago is that barely anyone had
| electricity 100 years ago and our standard of living has
| increased dramatically today.
|
| I expect a bump in our usage in the short term due to EV
| usage but from a household perspective I believe our
| electric usage will flat line. Heating and cooling are
| currently the highest usage of power in the domestic
| setting and large efficiency gains and alternative
| sources are available.
|
| I look at the power usage as a distributed problem and
| increasing local generation of power will create
| efficiencies. I also believe that there is finite amount
| of power that a USA based family of 4 needs. I think the
| alternate opinions assumes that the power needs are
| infinite.
| stevenhuang wrote:
| There's nothing absurd about local generation being able
| to fulfill/contribute to a large portion of the energy
| needs of a local residential area.
|
| People with residential solar do it all the time with
| payoff in less than 10 years.
| closewith wrote:
| The energy needs of a local residential area will just
| increase in response to the economically available power,
| but that's irrelevant as we're talking about agrivoltaics
| and farms use enormous amounts of energy.
| adrianN wrote:
| Energy use in the developed world is actually going down.
| Electricity use is expected to go up in the next decades.
| closewith wrote:
| In some parts, due to cost of supply and taxation. Demand
| for energy is higher than ever.
| lizknope wrote:
| Do you mean your own personal energy usage? Or your
| family? City? Country? The world?
|
| This is electricity use in the US from 1975 to 2023.
| Between 2010 to 2023 it has not changed a lot.
|
| https://www.statista.com/statistics/201794/us-
| electricity-co...
|
| This of course doesn't include things like gasoline or
| natural gas.
|
| My personal energy use has decreased over the last 25
| years. Increased insulation and new more efficient HVAC
| equipment has dropped by summer electric bill by 40%. My
| old car used to get 26 mpg on the highway and now I get
| 36. Work from home has dropped my gasoline usage even
| more. My computer would run 24 hours a day and idle at
| 180W and now it is 90W.
| closewith wrote:
| > Do you mean your own personal energy usage? Or your
| family? City? Country? The world?
|
| All of the above.
|
| > This is electricity use in the US from 1975 to 2023.
| Between 2010 to 2023 it has not changed a lot.
|
| Due to the cost of energy ballooning, largely due to
| taxation. However, the pent up demand is higher than
| ever.
| mapt wrote:
| Land near energy demand is not scarce almost anywhere. Where
| "near" means "Within 1000km". And it doesn't need to be near.
| Transmission lines are cheap and highly efficient
| infrastructure if you have a sensible process of land tenure
| (whether via routinized/generous eminent domain, Harberger
| Taxation, or other means).
|
| Moving electricity is among the cheapest, most efficient
| industrial processes that exist.
|
| *With all due respect to the Maldives, Gaza, Hong Kong, et
| cetera
| grumpy-de-sre wrote:
| And don't be sleeping on the potential of UHVDC
| transmission.
| mapt wrote:
| This is like the potential of High-Speed Rail.
|
| It isn't a theoretical, it's something China is 30+
| completed projects deep on. The technology existed
| decades ago. We just treat infrastructure like it's an
| impossibility here.
|
| https://en.wikipedia.org/wiki/Ultra-high-
| voltage_electricity...
| closewith wrote:
| What you and the GP are discussing are fundamentally
| different solutions to agrivoltaics. One is inherently
| decentralised (not only decentralised power generation,
| but also local nitrogen fixing and reduced water demand)
| and the other is Just A Better Grid(tm). Just A Better
| Grid(tm) is inherently valuable, but it's not a
| substitute nor is it in competetion with agrivoltaics.
| grumpy-de-sre wrote:
| Was in Northern China recently,
|
| Got to say the shiny and non-rusted transmission pylons
| in Hebei got me more excited than was probably warranted.
| I don't think I've seen a shiny pylon before, I guess we
| mostly just stopped building them decades ago.
|
| On the topic of agriculture I was very impressed by all
| the polytunnels we spotted from the high speed rail
| heading north out of Beijing. Every valley, and nook and
| cranny was full of them.
|
| Took a couple photos of a small town in inner Mongolia
| that we passed, was amazing seeing green crops in the
| middle of a Siberian winter.
|
| I believe this was a farm using recycled water to grow
| cut flowers https://imgur.com/a/kw1IDZ3
| ZeroGravitas wrote:
| I think those might be a specific kind of greenhouse
| rather than a standard polytunnel. The back wall is
| essentially a solar heat store.
|
| Here's an article on them:
|
| Chinese-style Solar Greenhouses
|
| https://ag.purdue.edu/department/btny/ppdl/potw-dept-
| folder/...
| mapt wrote:
| Yeah, this highly optimized passive solar design is one
| of those things that seems very obvious when energy is
| too expensive to waste on international transportation or
| excessive heating in a cold climate. Citrus production in
| 40 below zero.
|
| By pursuing artificially inexpensive energy we are
| doubling down on a great number of wasteful practices
| that are largely avoidable.
| grumpy-de-sre wrote:
| Thank you! That's exactly what they are. Even "higher"
| tech than I first anticipated.
| closewith wrote:
| To realise the benefits of local generation, near means on
| the order of 1,000m, not km.
| mapt wrote:
| What benefits?
| closewith wrote:
| Decentralisation and low capital cost, the points made in
| the article.
| dgacmu wrote:
| This depends too much on the specific grid topology to be
| generally true. For example, there is an underground
| transmission line that is one of the bottlenecks for
| about 30,000 people in my part of Pittsburgh. It's not
| too uncommon to have summertime glitches or outages due
| to overload on that one circuit. Any generation installed
| on the consumer side of that line helps - and that's
| several km.
|
| There's a planned solar project on an old partially
| reclaimed slag heap that will add generation proximal to
| that line, for example. (It's land that is too polluted
| for just about any other use, which is a fantastic place
| to stick some utility scale solar while still staying
| within the boundary of the city.)
| wongarsu wrote:
| At least in Europe, building transmission lines is a much
| longer process than building solar. Partially because of
| the complexity of acquiring land from a large number of
| owners, but more importantly because of NIMBYs that do
| everything to oppose new transmission lines that might
| disrupt the landscape. And some of the NIMBYs own the land
| you need to build the transmission line. Building a 1000km
| high capacity transmission line is a multi-decade project
| in this part of the world
| blitzar wrote:
| Roofs near energy demand is plentiful almost everywhere.
|
| I am lazy, I like to start with the low hanging fruit first.
| closewith wrote:
| > I am lazy, I like to start with the low hanging fruit
| first.
|
| Then you should be looking at agrivoltaics before rooftop,
| as they are much cheaper in developed countries where the
| cost of rooftop solar is dominated by installation cost.
| phr4ts wrote:
| If this is target at developing nations, theft of the solar
| panels will be a major hindrance.
| thinkindie wrote:
| something similar came out a couple of years ago for growing
| lemons in the south of italy with solar panels providing shades
| from an ever increasing temperatures
| https://www.bbc.com/future/article/20230424-how-agrivoltaics...
| leemelone wrote:
| This is a pretty dumb idea. This article is from researchers at a
| University. Has anyone done this for real without a grant
| subsidy?
|
| I understand the interest in maximizing space utilization, but
| this just doesn't make any sense.
|
| Some replies indicate field setups for solar should take priority
| and tractor/equipment systems should adapt to these new systems.
|
| Crazy stuff.
| hannob wrote:
| 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 wrote:
| 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 wrote:
| 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 wrote:
| https://afdc.energy.gov/data/10339
| nanomonkey wrote:
| 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 wrote:
| 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.
| salynchnew wrote:
| 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), it seems
| like a very nice idea.
| rendaw wrote:
| The article's arguments don't revolve around landuse, and in
| fact the article doesn't discuss landuse at all.
| TZubiri wrote:
| Who complains about the land use of solar?
|
| Obviously not a bottleneck? There's millions of desert acres.
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