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I don't operate one but back in university did some calculations around these and another factor is that efficiency goes down with rising temperatures. If the panels are all on the ground, during summer they will heat up and there won't be much air circulation beneath them to help cool them off. So efficiency will go down for sure, and I'm not sure the 20% one time savings will compensate a forever-less-efficient running operation. I guess it depends where in the world you install them, if more towards the north it might be ok.

When experimenting with solar efficiency, I noticed that spraying the panels with water every half hour increases efficiency pretty dramatically.

The wet surface seems better at absorbing sunlight than the 'anti reflective' glass surface, and the evaporating water is a great cooler.

Since it uses so little water, I don't know why industrial installations don't do it.

In some areas, the water use just from cleaning solar panels becomes a serious issue (let alone using more water to cool them). It's not much water to spray on some panels you are experimenting with, but for a large installation it seems like it would be a lot of water.

The best areas for solar are hot, those are also likely to be the areas where water supply is the most constrained, so this is definitely a no-go solution

This is in Texas which is hot but there’s water.

Additionally power stations use steam turbines which require a lot of water. Some cooling water for misters would probably be a rounding error.

https://www.eia.gov/todayinenergy/detail.php?id=50698

https://www.seia.org/initiatives/water-use-management

Sorry if this is too basic of a question but for places close enough to the sea, would sea water for cooling and cleaning be an option? Too much salt residue?

Now I'm waiting for the seaside solar power plant/salt works proposal to pop up!

Seriously: Maybe residue wouldn't be an issue if it was never allowed to dry, but the corrosion-proof construction, drainage system, and pumping costs would be considerable. Then there's the 100 problems we're not aware of yet...

salt crusts are highly reflective, driving down light exposure pretty fast. Plus, salt water is corrosive.

> salt crusts are highly reflective

I think this will not be a problem, as the salt would be continuously washed away with new water. But the corrosion would be a problem indeed.

Maybe some plastic/epoxy/glass casing would help, but it might also hinder recyclability.

See my comment above. This water is being used to grow agricultural crops under the panels in Kochi airport in India.

https://www.newindianexpress.com/states/kerala/2021/dec/13/c...

In the Kochi airport in Kerala, India, the water used to wash the solar panels is used to grow fruits and vegetable plants right under the panels and these are harvested and sold.

The plants under the panels also reduces the heat under the panels and thus increases the efficiency of power generation.

This can be a nice way of getting additional income from the land and also tackles the problem of plants growing under the panels.

https://www.newindianexpress.com/states/kerala/2021/dec/13/c...

>spraying the panels with water every half hour

Sounds like a job for center-pivot irrigation! Just choose a model that can rotate at 2 revolutions per hour.

I never really appreciated how brilliant these are until watching this video:

https://youtu.be/7j1lMs7fcIQ

For large deployments of Earth-mounted PV you'll need a grid of drainage ponds to buffer runoff water, so you might draw from those. A control system would monitor temperature, PV output, and water turbidity.

The latter is important, since there's no sense dumping dirty water on the panels! Give the suspended solids time to settle out, or even add flocculants via a dispenser.

Don't try this at home. Cold water can crack the glass or cause other thermal stress.

True. But most panels are rated and tested for icy hail to hit it on a hot sunny day with the panel surface at 70 degrees C.

But obviously doing this repeatedly might not be good for it - naturally hail on a super hot day is rare.

The water would need to be demineralized in order to not leave deposits over the long term. That alone probably makes the idea unprofitable.

I wonder how much of that is the water increasing the effective surface area of the panel be acting as lens?

this is a very good point. would be good to see data for a couple of years of production and compare vs. traditional system. it's most of the time better to spend upfront for ongoing production increase. If 5% loss during 25 years, 20% upfront saving might not look that good anymore for a plant that pays back in 7 years or so.

The response of the company when the issues of heating, vegetation, snow, and rain is... I guess I am not impressed.

> The expert added, “I’m also concerned about the lack of airflow around the module in this system design. Glass-glass modules provide a good moisture seal, but I suspect the back of the module will have very high humidity with no airflow. Damp-heat testing will be important. Not sure what other organic stuff could grow back there, like fungus or mold or things that get in the J-box,” referring to the junction box that houses the equipment that carries electricity from each panel.

> Daniel Flanigan, chief marketing and product officer at Erthos, offered this response: “No developer is going to install an Erthos system without proper diligence and all of these issues…being resolved. Yet we are engaged in over a gigawatt of pipeline.”

Okay, got it. So because people are paying for it people should pay for it. Everyone knows something no one knows.

https://www.canarymedia.com/articles/solar/utility-scale-sol...

I agree. sounds like a red flag when they reply with "yeah everyone is buying it so your question is irrelevant" instead of providing a technical explanation/response. I am also skeptical on companies that raise too much funding (I can not imagine why they need $18million)

That's what they said about Theranos, too.

They’ve studied the heat dissipation https://www.erthos.com/modeling-heat-dissipation-in-earth-mo...

Consider the difference in borrowing costs now too. A 20% higher upfront cost means a 30% higher cost if you include financing over several years. So it will be good to see how the alternatives work out

Are you an owner/operator at a “smaller” scale? I’ve always dreamed of starting a “DIY” commercial solar farm. I’ve recently moved to Spain from Canada and have been looking at the news of these flat installations recently. Seems pretty ideal for the climate here (no snow!), land is cheap and there’s no frost line to deal with.

I was thinking that maybe it makes sense to have each corner of a panel on a concrete block to keep them up off the ground a bit and promote some air flow and keep the temperatures down. That might make it hard to walk on them to clean, though. But if I had some sort of Roomba like device to do the cleaning that might not be an issue…

Thinking about it there aren't many things that are as cheap an durable as steel and aluminum. You surely know how the amount of energy you get out of the panels changes with inclination and just laying them flat is only feasible if you aren't concerned with that loss per unit of energy output or your plant sits on the equator. But in that case you can massively simplify the mounting system and raising the panels up would make maintenance from below easy.

It doesn't feel like masonry or poured concrete walls will be a much cheaper substitute either. Wood might do in arid conditions with well behaved weather but you may pay in maintenance over time what you save at the start.

I think a better approach is to improve the yield per unit with either better panels (split-cell bifacials currently seem to offer a nice bonus in yield just from back-reflected light) or some other thing you can do to improve overall profit per unit land.

Of course there are situations land is so cheap it doesn't matter as a cost factor but after a point you would pay more in other infrastructure than you save again.

Wooden structure is as durable as metal, it can rot if wet, but metal rusts if wet. Both can be painted, but its expensive and a bit polluting. Wood can be produced in systems vastly more friendly to environments than any current way to produce metal. Perhaps one day dropping it in from foundries in space might compete.

> but metal rusts if wet.

Aluminum does not rust, and galvanized steel will easily outlast a solar panel.

https://en.m.wikipedia.org/wiki/Hot-dip_galvanization

> Aluminum does not rust

While technically true, since rust is an iron oxide, the meaning behind the "metal rusts if wet" statement was more generic and less scientific. If you are a bit more forgiving in the interpretation of what was said, you could have acknowledge that aluminum does indeed oxidize over time. Aluminum just happens to have a nice property where the oxidation process creates a protective film that helps prevent further oxidation. Aluminum can be exposed to elements that destroy that film and result in accelerated oxidation.

And if you want to see something extra fun, look at what mercury does to aluminum without that protective film.

How does one get about starting a solar farm for commercial purposes? Do you have any guidelines or resources?

Hi. The most important step is permitting as it's a highly regulated industry. The rest is easier. Every jurisdiction has its own rules for permitting. Some govs want to push it more and make it easy (like Spain used to do it). Some don't need solar plants (like Switzerland). I heard Maryland in US is pushing it. I was planning to visit Maryland ministry of energy to learn more actually.

Why do you think Switzerland doesn't need solar plants? We're still in the middle of an energy crisis: While we have more than enough energy in spring and summer (lots of hydroelectric power plants), we don't have enough storage capacity to make it through winter with renewables alone. And plans to make an energy deal with the EU have failed so far.

Alpine solar power plants are a huge deal right now, and cause a lot of discussions. They provide big benefits over solar on rooftops in the valley, because they are usually above the fogline and provide better efficiency during winter.

This is the first alpine solar power plant that's fully operational since August: https://www.axpo.com/ch/en/about-us/energy-knowledge.detail.... It's mounted on a dam and thus had less issues with permissions (as it's mounted on an already existing structure with existing power infrastructure).

Here's an English article about two big planned projects in Gondo and Grengiols: https://www.swissinfo.ch/eng/mountaintop-solar-farms-spark-t...

I had really wanted to setup a utility scale solar power plant in Switzerland and did some research and could not find a way to do it nor en example of it (except rooftop solar panels which is common). Switzerland is already energy independent (60% of electricity generation is hydro, 34% is nuclear). This is a great mix comparing to fossil sources in many countries. And mostly explains low inflation in the country I think.

For 20+ years I have wish we literally had just build one more nuclear plant, we could easily have done this and would be fine and independent by now. But sadly we have to investigate all these ideas instead of just going with a solution we know works and is literally just a matter of spending the money to solve the problem.

Relaying on EU is just a terrible idea.

I'm not necessarily against some things like these solar on a dam, but I wish we just look at the problem, picked a solution, took on the debt needed and comprehensively solved it in one project.

The referendum to shut down nuclear power plants would have shut down that new one too... but anyway my impression is that there are no recent nuclear plants built anywhere, are there?

There are nuclear plants built still. Finland just finished a new plant that produces a lot of electricity. South Korea just built a whole bunch of new plants in the UAE. There are plants building in UK, in the US, in China, in India. Finland is build more as well. France is planning to build more. Poland has just decided to make nuclear its way to get away from coal.

Nuclear isn't doing fantastic, but new reactors are still built.

Switzerland has now overthrown the idea to shot down the reactors and they will stay open for many years more. But we don't plan to build new reactors either.

Had we built a new one, I don't think we would have voted to shut it off.

We could also get in contact with GenIV companies and try to be world leading with some next generation reactor.

My approach would be to build 1 Gen3+ reactor such as APR-1400 or something like that we start to build as soon as possible.

Then we also plan on building GenIV reactor such Terrestrial Energy ISMR or Moltex Energy Stable Salt Reactor. Eventually when we actually want to replace our existing fleet, we build more of that type.

@panick21_ we should get to know each other. I'm in Switzerland too. I'm not an experienced HN writer. Is there a way to exchange our contact details privately here?

I own one of these too. Sounds like it might be similar location to ush, as I deal with snow, sheep, etc.

I got mine during my windfall cash earning years in big corp. Great economics for a large W2 earner: 30% funding from gov, 30% funding from immediate depreciation, and you can lever the rest. Infinite IRR.

There are a whole network of developers who package the deals and then match it with financing. I still can't believe every dentist in America doesn't own one of these....

The 2 biggest problems you'd want to solve for first are (a) who will buy the power("offtaker") and (b) where the solar project will be placed. If it's commercial, often it will be at the offtaker's location. There is a competitive industry competing for these customer already of course.

How about a modified approach that raises the solar panels. One could use wood poles with steel wires to suspend the panels. That way you could service from underneath and even manually wash from underneath (e.g. using a custom made roller that you swipe from underneath).

Like a floating dock ? Or a suspension bridge ? I like the idea , might be cheaper than all that steel.

Lay those panels flat on a slope? Of course you need a slope to start with. What does cost more, steel frames or digging the ground to create rows of triangle shaped embarkments /\/\/\ ?

Is there a way I can contact you personally? I am looking to start a solar plant business in Southeast Asia and would love to connect.

Well, this is texas but who knows... It's def unclear but maybe, among other things, they poured some minimal concrete underneath in a matrix for earth movement (?) and some basic cooling/heat sink with it to address these issues at least nominally?

1/ Would this effect the interest rate for the first couple of plants?

2/ Do you think there is a future for robot cleaner? Some new companies are already 90% down from recent SPACs.

how do you clean it?

Sand and crap is going to blow across that and I don't see a practical way to get it off.

I'm not sure those panels are rated for people walking across them, so robots?

I can imagine that moss/algae is going to be a problem, as it start growing in the corners where all the dust gets trapped and is kept moist.

They have a little robot that cleans it every night. Watch the video on their website.

https://www.erthos.com/