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A 100MW solar farm in Texas will mount panels directly on the ground

335 points| orangebanana1 | 3 years ago |canarymedia.com | reply

376 comments

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[+] ush|3 years ago|reply
I own and operate a utility scale solar plant and i've always found it inefficient to spend 180k USD per MegaWatts for steel and aluminum structures to hold those panels. I've always dreamt of "my next plant will not have these steels" and my friends in the industry say it's impossible (like they all do say for new things). I hope this solution is a good one. The challenges are: 1) Snow: when it snows, inclination (22degrees in ours) helps snow blocks slide down usually in 2-3 days. when panels are completely flat, snow can stay on panels for weeks. how to solve that in large scale plants? 2) Natural vegetation that grows by itself: We deal with them with the help of sheep. They grow everywhere, under the panels, around the panels. As the panel covers 100% of the surface, no sunlight means no vegetation beneath? Is this for sure? Because there is no access to do any work beneath the panels after the installation. 3) Underground animals: Moles, mice (even snakes) etc live beneath the soil and they open holes to the surface and come up. Before, they could not access the panels because they are 1 meter up on the steel structure. Now they will have easy access to panels and cables. Will they cause harm? A snake sliding on the panels is ok? 4) Earth moves. After 5 years, some structures went deeper into the ground. I don't know if it's gonna cause a problem
[+] vasco|3 years ago|reply
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.
[+] gorbypark|3 years ago|reply
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…

[+] blkhawk|3 years ago|reply
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.

[+] ramraj07|3 years ago|reply
How does one get about starting a solar farm for commercial purposes? Do you have any guidelines or resources?
[+] sgt|3 years ago|reply
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).
[+] pmontra|3 years ago|reply
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 /\/\/\ ?
[+] nubela|3 years ago|reply
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.
[+] emeril|3 years ago|reply
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?
[+] algo_trader|3 years ago|reply
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.

[+] KaiserPro|3 years ago|reply
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.

[+] infogulch|3 years ago|reply
Finally someone saw the light and accepted the superiority of Factorio's flat solar panel design. Why dump so many resources into fixtures to eke out every last drop of efficiency when panels are cheap enough to just spam as groundcover? :)
[+] jacquesm|3 years ago|reply
This has been exactly my strategy. My first setup had two leafs of 8 panels each, tracking both azimuth and elevation. It was fragile, finicky, required a lot of active components and ultimately cost more per Watt that it put out than if I had simply laid the panels flat. Which is exactly what I did with my current installation (16x265 and 26x365). Another advantage of panels that are flat is that they are much less prone to being lifted up by the wind, you can mount them flush and the wind barely has any grip on them. They also do not shade each other at all, no matter what the angle of the sun.

Double axis tracking systems when they work are very pretty and technically satisfying, but ultimately those are not the right criteria by which to evaluate a system that has to be reliable, storm proof and that has to last a decade or more after installation, preferably without any service.

The weak point in the current installation is the cables and the connectors, that is something you can't really get away from. After dismantling a few older setups and having a good look at what remains there are two things that stand out for me: Make sure all cable joints are made in the shadow of a panel and tie down your cables on the underside of the support structure so they don't flap about in the wind and are not exposed to direct sunlight. Over time they'll get killed and especially with series connected panels (the bulk of them) this can lead to spectacular results (of the wrong kind).

[+] elihu|3 years ago|reply
Actually, the game art uses tilted panels (crammed closer together than they'd be in real life, so the shadow of one falls on the one behind it), though I admit I did think of Factorio solar panels in the sense that in the game you can make an area inaccessible to pedestrians by spamming the ground with them.

https://wiki.factorio.com/Solar_panel

[+] JoeAltmaier|3 years ago|reply
From one point of view, they are exactly as efficient as tilted panels? If your metric is sunlight intercepted per acre, then 100% is as good as it gets.

Tilting gets a better angle of incidence with the sun, which matters if that improves conversion rate (does it?).

If you have plenty of land and cheap panels, then your metric might be dollars-per-watt. Then this solution is a big step up. Less cost per install means more money for acres. You end up with more acres installed, you have more electricity.

And I suspect this is the right metric for some areas (like Texas), since panels are cheaper every year and they have plenty of acres.

[+] idiotsecant|3 years ago|reply
Seems weird. How do you service it? How do conductors work? How do you keep random junk from blowing on top of it? How do you clean it? The photo in the story just looks like a giant square of PV material. Is that really what this is?
[+] reddog|3 years ago|reply
Will Prowse did something similar (much smaller scale) on his YouTube channel last year. He set up a 6000 watt ground mount array in about 40 minutes and discusses the trade offs here:

https://youtu.be/71vME5k-oiw

[+] photochemsyn|3 years ago|reply
Interspersing standing panels with crops looks to be an effective strategy, some crops suffer from too much sunlight and require a little shading for optimal production (many vegetable-type crops fall into this category). Some strategies employ vertical bifacial panels. See:

https://youtu.be/lgZBlD-TCFE

Solar Panels Plus Farming? Agrivoltaics Explained

[+] rhacker|3 years ago|reply
His is more or less temporary.

What's great about him though is he already has a link up to the power company, so as he sees fit he can just reduce his bill by flaying them out in his courtyard. That or just mine btc/etc...

He's still an awesome dude and has helped me set up my own solar in the number of videos. Even better is his forum:

https://diysolarforum.com

[+] walrus01|3 years ago|reply
It is correct that mounting costs and labor can be a large portion of the total BOM.

Even for a large off grid whole home PV system that can operate through December/January at high latitudes.

Let's say for an example you wanted to DIY a PV system that would be much too large to fit on the roof of a normal sized house.

Go calculate the cost of buying 30000 kW of good quality 72-cell PV panels rated at 380W STC each. It'll be something like 80 pieces at about $130 per piece.

Usually would ship as 20 panels per pallet, so call it four fully loaded pallets of 72-cell panels.

At 34 cents/W STC rating, PV panel cost from distributor something like $10,400 to $12000 USD.

The foundation work and poles/racking to do a basic ground mount will be a huge cost on top of that. Labor is a big part of it. If you're hiring people to build it the labor and ground mount gear and things like basic foundation work/screw piles/steel tubes set into concrete could easily cost you another 10 grand from a local contractor.

Something generally along these lines or an industry competitor of it:

https://www.ironridge.com/ground-based/

(Not discussing inverters/charge controllers/batteries/disconnect boxes and wiring here).

[+] Klasiaster|3 years ago|reply
Dead ground is not so good for biodiversity, with the standard way you have wild grass and flowers beneath.
[+] bilsbie|3 years ago|reply
We’ll the cost isn’t just the racks

You’ve got to deal with permits for the structures. Installation. And then you have to do lawn trimming around all the racks. This can save on all of that.

[+] asciimov|3 years ago|reply
Not sure where they are building these but I’ll tell you hwhat, fire ants love electronics and they are found in the majority of this state. Putting these right on the ground is just inviting destruction by critters.
[+] randyrand|3 years ago|reply
Solar inverters are always water proof, sealed, and potted. The ants will have their work cut out for them.
[+] djcannabiz|3 years ago|reply
thats really interesting, thanks for sharing! a google search for fire ants electrical equipment brings up a website on ants conducting electricity and shorting circuits. I had no idea that was an issue
[+] DaniFong|3 years ago|reply
i swear those buggers sense where the volts are
[+] dwighttk|3 years ago|reply
even worse: Rasberry crazy ants
[+] mycall|3 years ago|reply
> "Install in half the cost, half the time on 33% of the land"

If the panels don't point directly at the sun, then you lose much of the efficiency.

I wonder how the robot cleaner handles bird poop.

[+] s1artibartfast|3 years ago|reply
It all comes down to the economic tradeoffs. Panels are cheap and everything else is expensive.

If you can get 75% efficiency for half the cost, your return on investment is 50% higher

[+] dahfizz|3 years ago|reply
> If the panels don't point directly at the sun, then you lose much of the efficiency.

This is true for a single panel. But the amount of sunlight which hits an acre of land is constant. If the land is 100% covered with panels, the panels will collect 100% of the available sunlight.

Installations that tilt the panels have lots of space between the panels.

[+] constantlm|3 years ago|reply
Sounds like they're pretty confident this isn't an issue:

>Our fees are based on the plant producing at its optimal performance. If the plant underperforms for any reason, we curtail our fees – creating strong incentive and perfect alignment with the long-term asset owner.

[+] sorenjan|3 years ago|reply
I don't understand why they cant dig some kind of trench or mound to put them on at least, to angle them more towards the sun. There's plenty of agricultural equipment designed to cultivate soil (first example I found[0]). That could take care of the drainage as well, although I don't know how much it rains in Texas.

[0] https://www.asa-lift.com/asalift/producttypes/bodenbearbeitu...

[+] legohead|3 years ago|reply
You get the majority of the power when the sun is directly overhead. You can make up the lost difference by the space saving and just adding more panels.
[+] drumttocs8|3 years ago|reply
Most utility scale installations don’t track the sun- too much cost. This takes cost-saving to a new level though.
[+] Hermitude|3 years ago|reply
Horizontal panels also collect dust, so they still need to be propping them on the north side.
[+] conor_f|3 years ago|reply
Really I don't care where or how the panels are placed.

All movement towards renewables is good, no matter how "inefficient" it is vs fossils

[+] felgueres|3 years ago|reply
The reason they are tilted is to maximize irradiance hitting the panel. At a 0 degree angle (flat on the ground) you get a a lot around noon and then very little.

This approach surely reduces land usage but what is the output per acre?

I’d be really surprised if it’s higher than with tilted modules.

[+] 1024core|3 years ago|reply
> From 2010 to 2021, the levelized cost of installing utility-scale solar fell 88% .... But in the last couple of years, supply-chain issues have halted these price declines globally

How many "couple of years" have there been between 2021 and now?

[+] anko|3 years ago|reply
aussies are doing a similar thing although they install by pulling via tractor and the panels concertina out see https://suncable.energy/

they are doing an underwater cable to supply energy to singapore

[+] gumby|3 years ago|reply
The price of panels has fallen so much that installation is now a significant proportion of the cost. So this is a good idea.

But without any airflow behind the panels they will heat up, which will reduce efficacy. This is the main reason BIPV (solar roof tiles, in this case) has failed for decades. So this is a bad idea.

Which is it? I suspect, based on the BIPV example, that this will probably not work. It would be cool if this suspicion turned out to be wrong!

[+] laluser|3 years ago|reply
> less than 2.5 acres per megawatt

This is actually quite amazing. I wonder what the lifetime is for the panels.

[+] drumttocs8|3 years ago|reply
Should be an interesting experiment at a decently high scale. Time will tell if degradation due to dust, pests, etc is negligible enough to make the avoided maintenance costs worthwhile.

I think we would all argue that the opposite is better long term, though: we should be installing panel covered parking across the nation. Certainly more cost, but so many benefits. Including serviceability!

[+] kumarvvr|3 years ago|reply
I am curious, how much does a sturdy stand cost for a solar panel set? Are there significant cost savings on the support structure? EDIT : Ok, its 20% of total cost. Significant.

Also, being completely flat, dont they lose avg. units generated per day? I though placing them at a N-S inclination helps with capturing more energy.

[+] ElijahLynn|3 years ago|reply
From the picture, it looks like the dirt will eventually wash onto the edges and it will be difficult to clean as you can't just spray it off and have it wash off with gravity. I'm confused as to how this will stay efficient in the long run.
[+] miohtama|3 years ago|reply
They clean it with robots

> Automated nightly robotic cleaning of entire array prevents hot spots due to soiling.

[+] motoxpro|3 years ago|reply
Build a 1ft tall platform out of dirt/gravel and tilt the whole thing a few degrees. Solves this probs.