I’m no farmer but wouldn’t putting a whole bunch of stuff in a field make it difficult to drive a tractor through it? Like have you seen the size of modern tractors? These panels will need to be 20ft in the air with support posts really far apart to accommodate seed drills and sprayers and other equipment that the tractor pulls behind it.
To some extent that falls into the category of "fiddly details." Solar panels are probably not the best choice for use alongside bulk harvested crops like corn, wheat, soybeans and even potatoes, but an awful lot of "produce" crops are harvested by hand.
The reason I say "fiddly details" is because questions like "what's the best spacing between rows of panels" and "do I plant under the panels or just between rows" can be decided as people look into available equipment, land prices, crop variation and flexibility, etc.
It's absurd now but... imagine those crop-water-er things, with a central pivot (ed: "central-pivot-irrigation").
What if instead of just a line of watering, that rotated around, it was a vast overhead rotating circle? Like 80% by area solar panels overhanigng. But also, one radian with all the farm stuff: watering, tiller, planter, harvester? An polar-plotter of tools, with solar panels taking up most everywhere else.
I’m actually experimenting with building one of those- the problem is the forces involved compared to the irrigator which is basically just suspending water pipes over the ground
maybe i'm misremembering, but I was under them impression that the water pressure drove the platform. was i totally wrong on this? i ask, as i would never have guessed adding the weight of solar panels to that would be viable without possibly using some of the generated power to drive a motor.
Note the room to drive between panel rows and for "boom mowers" to spread out behind a medium tractor and reach under the panels.
There are also many types of vehicles used in agriculture from two storey high broad acre heavy duty combine harvesting monsters to small narrow self propelled engines that run through tree trunks in orchard with various attachments to mow (sprung mowing rings), shake trees (to make fruit fall), spray leaves, trench (for irrigation, drainage, etc).
Also, see: "Agri-bots" - a revolution not yet complete in small driverless autonomous helpers to run 24/7 weeding, spraying, picking berries, using solar, etc.
>improved fleece on merino sheep grazed under panels
Makes sense. I'm not sure the exact care instructions, but I'm pretty sure "store this garment outside unshielded in the baking sun and pouring rain for many months" isn't the official recommendation for wool.
If available, sheep (and other animals) will seek cover during heavy rains and periods of high heat stress. This protects both the sheep and the wool, and both factors improve quality.
I wouldn't be surprised if the diet improves as well, due to healthier grass, higher plant biodiversity, and higher abundance of (tasty and nutritious) insects.
Paradoxically, primary productivity will often increase with added shade, because photosynthesis shuts down at even mildly elevated leaf temperatures (~85 °F). Those vast impressive corn fields will often overheat and shut down around 10 AM, and don't start photosynthesizing again until 4 PM.
In ye olden days farmers would plant a widely-spaced grid of "farmer's trees."[0] These are a category of trees (eg black locust) which 1) provided shade and windbreak, 2) coexist with crops right up to their trunk, 3) have deep tap roots bringing up minerals and water, 4) drops fertilizing mulch, and 5) produces nutritious animal fodder (pods) which self-dry and store on the tree itself. Clever farmers!
For mechanized farms you can choose a planting pattern and varieties that permit machinery to drive right past the tree without losing much area on "gores." Typical density was about 20-30 trees per hectare, so it also stores a bit of carbon.
Personally I prefer trees, but ultimately we need both types of systems.
Wool has a protective layer of grease, the same thing that makes your hair feels "greasy" if you don't wash your hair for a month. This grease is washed away during wool processing and sold as lanolin.
And also, the degradation that you see on sun-damaged clothing is mostly on the dye, not the underlying fabric itself.
It's also true that lanolin + shade and rain cover is better than lanolin alone. No protection is 100%.
> degradation that you see on sun-damaged clothing is mostly on the dye
"Mostly." We agree damage is done to the fiber. ;)
By design, modern dyes often act to protect fibers, soaking up energetic photons before they can damage the fibers themselves. In their absence, undyed fibers can be more susceptible to damage.
> the degradation that you see on sun-damaged clothing is mostly on the dye, not the underlying fabric itself.
UV light will absolutely wreck most things, including fabric. Fabric left outdoors unprotected for a summer in Southwest US will be brittle and tear apart when handled. Plastic that isn't UV-protected will crack in about two summers. Hoses left in the sun will develop multiple leaks in 3-5 years, pretty much no matter how robust the marketing claimed they are.
There are some 68 million+ sheep in Australia and the barely 25 million people are facing a housing shortage ATM .. there's never been sheds and houses for sheep in Australia aside from shearing sheds that only see once per annum usage.
As you can see here [1-4] paddocks have trees, dams, etc.
I had been assuming that even if there was not a shed, there would be ample trees for the animals to take shelter when needed. Wild to me that providing shade had been neglected by the shepherd.
Vertical bifacial panels are one approach that doesn't interfere with tractors and equipment, and still have comparable generation (with twice as many panels, so more expensive):
> "For conventional ground-mounted systems, the scientists considered a tilt angle of 20 degrees and an average estimated energy yield 1,020 Wh/W. For the bifacial vertical west-east oriented systems, they assumed a bifaciality factor of 90% and an annual energy yield of 999 Wh/W, while for vertical systems with a north-south orientation the annual energy yield was indicated at 926 Wh/W."
This[0] is a berry farm I was just at. As you can see it’s already covered to protect from extra sun. No tractor could fit anyways.
This[1] is one version of agrovoltaics. The solar panels act like window blinds. They can be configured to follow the sun but also can be configured to “provide optimal shade/cooling throughout the day”.
"This[0] is a berry farm I was just at. As you can see it’s already covered to protect from extra sun."
Erm, I can see a greenhouse. I think they are made to increase temperature for the plants and not to protect from extra sun. Strawberries like sun and would not benefit from shade, unless we are talking about very intense sunlight and not much water.
Most plants usually want as much sun as they can get, so long as the temperature stays in their desired range and enough water is avaiable. So in dry places with lots of sun, acrovoltaics can make some sense, or for plants that like indeed shade, like tomatoes. But it is really not a magic bullet for growing corn and harvesting electricity at the same time.
Sheeps grazing under solar panels seems like a working solution that does not need too much effort around it.
A lot of plants doesn't like and cannot survive the sun at central hours unless you water them like crazy. Basically you are watering to avoid dehydration, but not producing, like drinking in the desert. A lot of plants evolved to thrive near/under trees.
Greenhouses can tame the sunlight, and usually they are painted in white in regions of too much sun (https://m.youtube.com/watch?v=Rl6tMOU84tk). Also, greenhouses are hot but very humid, so the plants doesn't dehydrate as fast.
I could imagine an scheme that instead of watering (costs money) you shade the crops with panels (earns money) during the worst of the day.
I live in the hot and humid Deep South and my strawberries do not mind the sun. There’s a local berry patch that has lots of different berries, including strawberries, and no shades in sight.
What’s in OPs image is a greenhouse. The sides can be closed if low temperatures are coming in at night.
The examples given in the article are mushrooms and broccoli. Obviously the primary and first use cases would be things that want some shade (in the local environment).
Most of the examples I’ve seen are small scale hand pick farming. But there is nothing about 20’ spans that are outside our technical abilities today. This seems like a rather small obstacle to overcome. Of course this still says nothing about the economic feasibility or impacts.
Thinking more about it, you wouldn’t even need 20’ spans. You’d have articulating struts coming off of a central point between the rows. Panels can be adjusted out of the way of equipment when it needs to pass through if it is interfering.
The crops that are best suited to giant tractors also tend to be less suited to agrivoltaics.
They also include energy crops, so you can go from producing no food on land with unprofitable crops that take subsidies to growing food on the land at a profit and producing energy.
The land taken up by energy crops exceeds the land needed by solar by over an order of magnitude.
Solar panels are already being put on fertile land (in UK), so if that land can get dual-use and not waste it's potential for food provision then that seems more optimal.
That said, these threads always confirm in me a belief that we need to cut human population replacement to save the planet and our own species.
I can tell you are no farmer. No tractor is needed in a field maintained by grazing. If tbe panels are mounted high enough sunlight will be cast on the ground for a period each day.
I am a farmer, and this doesn't make sense. Grazing fields aren't really growing crops.
Even if this is just crops that are picked by hand (it mentions broccoli), they typically still have huge machines follow the laborers for them to deposit them in: https://www.youtube.com/watch?v=bKyxMKO2kyU
I can't see any good way to harvest a field with solar panels that isn't so inefficiently laid out that it would be better to have two separate fields.
I am not a farmer, but am interested in watching the development of agricultural tech.
>> I can't see any good way to harvest a field with solar panels that isn't so inefficiently laid out that it would be better to have two separate fields.
Would there be scope for smaller autonomous machines? Presumably, there should be some crop configurations that could benefit, but we don't yet have all the results of experiments currently running. Here in Japan, farms are typically much smaller, so there's perhaps greater scope for agrivoltaics than in industrial scale farms in USA.
Pastures used for grazing are managed intensively using big machines. (Source: I live next door to a large dairy farm. Pastures irrigated with centre-pivot systems.) Pastures get replanted/supplemental sowing every so often, weeds get sprayed with herbicides, fields get mowed to maintain uniform growth after they've been grazed...
Factory-farming dairy. Nothing at all unusual. If you have some bucolic vision of cows peacefully grazing all day, being led to a milking shed twice a day, flies buzzing in the sunshine... disabuse yourself of the illusion. When people say "factory-farming" they mean something far closer to "factory" than "farm". To keep cows at maximum productivity, dairy farmers (others farmers, too, I'm certain!) are squeezing the maximum productivity out of their pastures, and that means working them intensively; constant management = plenty of machinery.
I can't for the life of me imagine how these operations are going to continue to produce at these levels without the fossil-fuel subsidy they depend on completely.
I grew up in Pennsylvania Dutch country so rich with cows that Milton Hershey located his chocolate company nearby. I grew up on over 100 acres of that same farmland doing farming things. My Dad in Florida used was a member of the National Cattle Man's Association. I feel grounded in views of farming and acknowledge that my experience has nothing to do with factory farms. Frankly I'm a little embarrassed by the brain power exerted on this thread. I have been a member of both Future Farmers of America, and 4-H.
