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Comment by femto | Hacker News Reader

> use land more efficiently

This might not be such a big deal. I appears that it makes sense not to pack panels in tightly, but to space them apart so pasture can grow under them. In this way, the land is essentially "free", in that panels can be put on land that is already being used for pasture. Apparently it benefits the pasture, as condensation from the panels irritates the pasture, leading to more growth [1]. The sheep also benefit from the shelter, the panels providing shade and reducing wind chill, leading to lower mortality. A win for the farm production and a win for energy production [2].

[1] https://www.theguardian.com/australia-news/article/2024/jun/...

[2] https://extensionaus.com.au/energysmartfarming/agrivoltaics-...

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Depends where you are. It might not be a problem in Australia, but it very much is here in Switzerland. Space is at a premium, and NIMBYISM very strong (and includes not in my mountains).

Most of the costs of building a solar plant is the years of bureaucracy, and the majority of projects (the ones that get built that is) end up massively reduced in scope. So more expensive but more efficient panels are a boon, and won't change much in the total price.

NIMBYISM strong in Oz also alas.

True, but much more of a problem for wind and transmission than solar per se.

Been some cookers claiming glare problems from solar. And a lot of "oh no the loss of farmland" when evidence is good for co grazing and some cropping.

https://phytonics.com/en/home/

Good resource to solve any solar panel glare problem. Useful for solar on the free spaces around airports as well.

I imagine it’s strong anywhere people have back yards.

Not-in-my-backyard-ism?

Solar panels generally get less efficient with age. So many existing solar farms will be looking to upgrade/replace panels one day, something that generally doesnt require much paperwork.

Do you know if there is a reason PV farms avoid concentrated photovoltaics?

https://en.wikipedia.org/wiki/Concentrator_photovoltaics

This should allow swapping out a small PV module and more cheaply upgrade a farm as PV module efficiencies improve in many small steps.

One could argue that one would have to upgrade the inverters at every step, but that would be wasteful: just size the inverters to accomodate many future increments (if inverter lifetime is bottleneck one has to estimate future efficiencies of PV modules, if inverter lifetime is not the bottleneck just use the thermodynamic maximum efficiency to size the inverter once, and only upgrade the PV module over time).

The panels are so cheap that it's not worth fiddling with optics. The economics works better with as little glass as possible, just enough to protect the cells. This also killed tracking solar, which being a mechanical device has maintenance overheads.

There's not as much mileage in panel upgrades as you might expect. It's not Moore's law, it's much slower, and surprisingly the rated life of inverters tends to be shorter than that of panels. Once panels are installed they're going to be left alone as much as possible (because that costs money) for twenty or more years.

The panels are so cheap that the optics shouldn't be compared to other costs like the price of panels but to the price of inverters and installation, maintenance,...

Look at the price for upgrading the solar farm over time, N times the price of solar panels may still dwarf the cost of the optics.

> This also killed tracking solar

A great deal of the utility-scale solar in the US uses 1-axis tracking.

https://emp.lbl.gov/sites/default/files/utility_scale_solar_...

"Projects using single-axis tracking have consistently exceeded fixed-tilt installations since 2015, and dominated again in 2022, with 94% of all new capacity using tracking -- the greatest ever."

> Do you know if there is a reason PV farms avoid concentrated photovoltaics?

Concentration doesn't work on diffuse sunlight, scattered off clouds, dust, or the air itself. In non-desert regions diffuse sunlight can be significant fraction of total insolation.

Concentration is also more complex and can require cooling of the PV cells. On the plus side, very high concentration can increase cell voltage and hence efficiency.

Swiss could power entire nation (plus export some more) if they cared enough to harness all that kinetic energy of water coming down 3000m from the mountains. That's the last country with renewables problem.

Plus I see tons of solars here on rooftops, on new buildings etc. Colleagues with houses got some tax breaks so they poured some serious money into these and drive teslas basically for free (doesn't change TCO that much given how brutal repair costs or more frequent changes of those big tires & brakes are, but still, they have a warm fuzzy feeling about it).

Brake pads typically last the lifetime of a vehicle for an EV. 90%+ of braking is regenerative.

> given how brutal repair costs or more frequent changes of those big tires & brakes are, but still, they have a warm fuzzy feeling about it

Regarding brakes: that is pretty far from the truth as other sibling commented they use regenerative braking.

Tires - yeah. Well, except minivan or some pickups weights the same as Tesla so it is not like out of ordinary.

Sorry my bad, it actually makes sense re brake pads.

And those bigger cars - thats not majority on Swiss(=european) roads, we have tons of narrow roads, parking spots are short and narrow too. Roads with traffic generally look very different compared to US.

Do you have a source for your first claim? My understanding is that hydro is mostly saturated in Switzerland (https://ethz.ch/content/dam/ethz/special-interest/baug/depar...)

There's also very little appetite (and it's been the case since the 80's) for hydro anyway. Even before the biodiversity argument, simply moving whole communities is just no longer a thing.

It is installation cost what matters longterm. Panels with 20% more efficiency you get 20% more power for the same installation cost. Install cost is already a big portion of the cost for rooftop installation and soon will be for other types.

Yes and no. There is a movement to reduce installation and maintenance costs by blanketing ground with tighty-packed panels. This minimizes undergrowth, reducing the need to mow. Installing panels at only a couple feet off the ground means no digging or machinery during install. Having acres of panels edge-to-edge also facilitates robotic cleaners.

https://www.jurchen-technology.com/products/solar-mounting/p...

> the panels irritates the pasture

I think you meant irrigate :-)

> space them apart so pasture can grow under them.

Vegetables too! This operation is in the town where I live:

https://sproutcityfarms.org/jacks-solar-farm

Colorado is hot and dry, but like you say with pasture the taller panels shade the plants enough to give the them a break from the sun and heat. Too much heat and photosynthesis stops for a lot of plants.

Also just like for pasturing the panels help keep water from evaporating and creates three micro-climates within the micro-climate of the solar farm itself. There's cool and wet on the east side of the panels, cool and dry right under the panels, and warm and wet on the west side of the panels. I'm using "wet" liberally given that we get about 14-17" of precip per year.

Your mention of lower mortality for sheep surprised me, I didn't know it made that big of a difference, but it turns out that people farming veggies get the same benefit. I'm watching the video at the link above and the farmers keep talking about how much better it is working in the shade, and that's a good point. Vegetable farming is hard work.

Colorado isn't light-limited so we can afford this shade. The same can't be said everywhere, but the bottom line is that in many places solar farms can actually help crops instead of limiting them.

Like a solar orchard

All else being equal, spaced out panels or no you would still want as much electricity as possible out of the panels!

Honestly, having recently become an owner of a solar installation, these things are a pain in the butt. Solar panels are connected in series, and the current (thus power) in the series is limited by the least productive element in the series, meaning if you have something as insignificant as a speck of dirt on the panels can limit the current of the panels by as much as 20%.

Having these things unattended in the middle of nowhere would cause major maintenance challenges.

Have you looked into micro-inverters? Where each panel has its own inverter, thus mitigating the 'weakest link' problem as you describe.

Any particular reason why you did/didn't go for a micro-inverter setup?

I've watched videos about them, but the solar company didn't offer that kind of setup. I'm not sure how they would shake out cost-wise in years of ROI, versus a less efficient traditional string inverter.

I've also have three-phase AC at home, and battery storage, so not sure how it would combine with that.

I'd also need to look up installation requirements, particulary how it handles de-energizing the grid side when the power cuts out. My string inverter has current transformers installed at the connection point to the grid, so that it knows when the power goes away.

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