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Comment by oceanplexian | Hacker News Reader

On one hand it’s an interesting engineering challenge, but I am always perplexed how covering hundreds of square km of an ecosystem with glass is “good for the environment”. It sounds like something future generations will shake their heads at while trying to dispose of all the toxic waste.

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Hundreds of square km is not a lot, and the ecosystems where these systems would be installed are typically not rich havens of life. The US's power consumption would require about 6000-9000 sq km of solar panels (assuming ~15% efficiency) For comparison in the US there are about 13000-33000 sq km of parking lots, 93000 sq km of alfalfa cultivation, 69000 sq km of fallow agricultural land, and the mojave desert is about 124000 sq km. Yeah with gross mismanagement you might jeopardize the survival of some rare lizard or something, but it's a very far cry from a silicon wasteland.

> parking lots

This is how much of downtown Tulsa, OK is covered in parking lots:

https://i.redd.it/ukzcn1xx6cc91.jpg

There is no technological problem to covering a parking lot in PV, it's a question of the political will and money to do it.

That one image very powerfully captures the total and utter idiocy of car-centric development. Imagine if that thin sprinkling of actual buildings were reconfigured into one dense, car-free urban core…

That isn't car centric development, that is urban development in a city that fell into hard times. The whole area in the picture is about one square mile (i.e. it was the dense core of the city), and during boom times it was full of buildings. Many of the buildings were torn down when their owners could no longer afford to maintain them and they were replaced with parking lots because they look a lot better than overgrown fields. As the city revitalizes, the parking lots will be built over and turned back into buildings.

I suppose we have different standards for what constitutes car-centric development. Even if all those parking lots were built up, I see a whole lot of pavement and not a lot of pedestrian / cycling infrastructure nor greenery (I looked on street view). I mean, there are 18-wheeler semis on those streets!

Add to that urban freeways with enormous junctions ringing this supposedly dense core, cutting off surrounding areas from car-free access.

Yes, the city center has some tall buildings. The car is still dominant on its streets though.

The problem with covering a parking lot with solar panels is that it's usually a lot more expensive than covering rural land with solar panels. The panels have to be mounted higher off the ground so vehicles can get beneath them, they're usually expected to have a reasonably visually-appealing design, and all the wiring has to be kept safely out of the way and inaccessible to pedestrians. This drives up costs.

If land was truly scarce, parking lot solar would be a good option but I expect most installations will use the cheaper option of just building solar farms a long ways away from people.

Solar parking lots also might make sense in situations where all the power is being used on-site, and it's cheaper in the long run than buying power from the local utility.

There's no scale shown on that photo. What is the total area?

I've never actually been to that city but that's a mid sized sports stadium you see to the left side. Tulsa I think is an extreme example, if you look at an aerial photo of Seattle from the 1970s there were a ton of "downtown" surface lots too, but now the land is way too valuable to use for that.

You can also see what looks like a regulation size baseball diamond to the top right side.

It'a really weird but there's a surprisingly growing base of farming amid a solar farm, where apparently many plants just cant stand the pure sun & benefit from some periodic shade during the day. I dont know how much I believe it but combined agriculture/solar use seems perhaps legit to be a thing.

Also, solar panels dont seem that difficult to recycle. There's already a decent & growing reclaimation market. Giant slabs of polysilicon, with perhaps some glass & metal casing, plus some bus-bars. Strip & toss into a chewer.

Solar panels up high can coexist with livestock and feed grass quite well it seems:

> ABC (Australia) RURAL [π]

> Solar farm trial shows improved fleece on merino sheep grazed under panels

> Sheep grazing under solar panels at farms in NSW's Central West have produced better wool and more of it in the four years since the projects began, according to growers.

> Local graziers have labelled the set-up a "complete win-win", with the sheep helping to keep grass and weeds down so as not to obscure the panels.

> In turn, the panels provided shade for the sheep and grass, and helped prevent the soil from drying out.

[π] https://www.abc.net.au/news/rural/2022-05-30/solar-farm-graz...

It’s known as agrivoltaics [1]. It works especially well with highly shade-tolerant crops like leafy vegetables, stone fruits, berries, etc., but also works with grazing or arable cultivation.

There are various possible configurations of panels that still allow farm machinery to access the crop beneath, and the crop itself is protected from heat stress, wind, heavy rain, and hail. Shading reduces evaporative water loss, lessening the need for irrigation, and the crop has a local cooling effect for the PV panels, which improves their efficiency.

According to an extended report from the Fraunhofer Institute [2], the main challenges are regulatory – at least in Germany, but I imagine similar hurdles in the rest of the EU. Essentially, difficulties obtaining building permits; negation of farming subsidies from enclosure of land; and obstacles to connecting to the grid and receiving feed-in tariffs.

Those challenges all seem surmountable, and there’s surely huge promise in the vast amount of land that would be unlocked for energy generation, never mind the synergies favorable for horticulture in particular.

[1]: https://www.ise.fraunhofer.de/en/key-topics/integrated-photo...

[2]: https://www.ise.fraunhofer.de/content/dam/ise/en/documents/p...

Very interesting.

I do wonder how robust these would be to wind storms/tornadoes/hurricanes (like we tend to get in the US).

Good question. A brief search suggests hail is the greatest common hazard to the panels. I guess they’re going to act like a sail in a hurricane or tornado.

> Also, solar panels dont seem that difficult to recycle. There's already a decent & growing reclaimation market.

Curious if you're basing this on firsthand knowledge? I know nothing about solar panels but I've read some stories[0][1] lately about difficulties recycling them, particularly older ones that were deployed 10-20 years ago and are now reaching EOL.

[0] https://www.discovermagazine.com/environment/solar-panel-was... [1] https://www.abc.net.au/news/rural/2022-01-17/are-some-solar-...

First Solar (the largest American solar manufacturer) has provided recycling for the panels they make since 2005:

https://www.firstsolar.com/modules/recycling

https://www.bnl.gov/pv/files/prs_agenda/2_krueger_ieee-prese...

https://www.firstsolar.com/-/media/First-Solar/Sustainabilit...

German company Flaxres recently completed a pilot scale trial for recycling silicon photovoltaic modules from any manufacturer:

https://www.pv-magazine.com/2022/07/22/industrial-process-fo...

Since the vast majority of PV modules that have ever been installed are still working there isn't much recycling yet. Most of the mass of a PV panel is mundane things like glass and aluminum (and perhaps steel for ground mountings) that are either eminently recyclable or easily disposable in mass.

Ultra-pure silicon is intrinsically valuable. Anyone dumping used-up panels is an idiot.

Matter of interpretation. Is humanity at all good for the environment? Some would say no. Solar is clean and deserts are mostly, well, deserts. And climate change seems much worse than having a tiny bit of our deserts being used for PV farms.

Pointless to discuss. Deserts are a really dumb place for solar farms.

Solar will coexist with agricultural land and existing reservoirs, and benefit both.

I'm not saying pave over the mojave desert with PV, exactly, rather that a dry salt pan or ecosystem that has an absolute minimum of flora and fauna would be preferable.

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

creating massive hydroelectric dam reservoirs also has ecological costs

in terms of toxic waste it would surely be preferable to the percentage of electricity right now that is generated using gas, heavy fuel oil and coal.

Unfortunately the inhabitants of the Mojave turned down a major solar power project last year because of ecological disruption", aka "this wouldn't be pretty on our nature hikes."

Perhaps we can use the Salton Sea? It is at least acknowledged as a truly destroyed ecosystem.

I am sort of a nimby, but there's nowhere wild to protect anymore. Thanks Starlink!

I am less and less sympathetic to groups standing in the way of clean energy production because of any aesthetics issue.

However, I don't live there so I won't judge, though a wind farm got knocked back near where I live because it'd look like a windfarm and it was the greenies who knocked it back.

> It sounds like something future generations will shake their heads at while trying to dispose of all the toxic waste.

No, it doesn't. They will be far too busy handling coal ash dumps from coal-fired power stations, and remediating landscapes laid waste by mountain-top removal coal mining.

This will be orders of magnitude smaller as a problem. They will be grateful we finally stopped using coal.

You just space them out a bit and life will thrive all around them. A lot of species will appreciate the shade.

34,000 square kilometers [1] have already been disturbed for surface coal mining.

Two points about that:

- existing energy sources already do a huge amount of damage to land (and in places like West Virginia, particularly environmentally sensitive land)

- that's land that can already be converted to solar without significant harm being done (the harm has already been done)

[1]: https://www.gem.wiki/The_footprint_of_coal

Wait until you hear about how we invented synthetic fertilizer and added 5 billion humans in as many as 100 years. Won't somebody think of the ecosystem!

We’ve already desertified tens of thousands of square km of land into parking lots / heat sinks. We could start by shading those abominations with solar panels.

Wait until you hear about roads.

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