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
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.
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
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...
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.
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.
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.
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)
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.
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.
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).
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).
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 /\/\/\ ?
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?
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? :)
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).
Covered parking and rooftop make so much more sense though. Why do we want to cover more of the natural world, our only world, with more of our silicate-derived trash?
Parking and rooftop ensure the structural protection of your cabling, while at the same time optimizing the positioning of your servicing ports. Slightly elevated rooftop solar can also significantly reduce the a/c bill of a structure (especially smaller houses in sunny environments) and parking helps protect the paint of cars.
As I was told last time I noted there’s lot of arid places you could put panel in, aside from ecological concerns arid places tend to be dusty and abrasive.
Wind kicks up dust, dust clings to panel, no rain for months on end, panels get covered up and scratched. Turns out there’s issues to using these spaces, and you need additional hardware (and thus have additional failure modes) to mitigate them.
Yes, they are also very fragile and take a long time to recover.
I think solar panels done right could actually help a desert though. Providing shade can allow some plants to thrive but most solar developers aren’t thinking about the ecology of a region.
How many of these mandatory impact assessments are identifying ways of improving the ecosystem with their installation? Obviously I don’t mean by by displacing carbon.
From a purely selfish human point of view, how important are desert ecosystems to the overall health of the planet and the planet's ability to support human life?
I feel like sacrificing the deserts to save the rainforests is a trade worth making - but is such a trade even possible, or is it not that simple?
This article actually suggests that desertification is a critical part of the Rainforest ecosystem.
There are important deserts and there are important grasslands and important forests. It seems a valid point that not all ecosystems are of equal importance.
Pretty well so far for whom? We've initiated a mass global extinction. There wasn't ever a competition to take over the world as a species - no award, no prize - no one and nothing cares.
The only way we've done it is by eliminating everything in our path. We've been excellent at justifying eliminating entire ecosystems - when will we stop?
Probably right before we've justified eliminating entire countries of people with the weapons of death we've developed by extracting every last resource for the ground by digging it up.
It would be interesting paired with some kind of heat sink.
Solar cells need a heat sink to keep them cool or else the efficiency sucks.
Deserts tend to be cold at night.
Capture heat during the day as a byproduct of using the solar panels, and use it at night for heating homes? Maybe I'm being too optimistic, usually things that improve efficiency don't actually work for some reason.
Rooftops are not that much land area. A few percent of a city landscape?
Further it's dangerous. Installation, maintenance become a headache and a risk.
Then, so many rooftops are not in optimal 'viewing locations'. Shaded by trees; shaded by neighboring buildings especially in a city.
It seems natural to a non-engineer to 'make electricity where you need it'. But rooftops don't scale with need, not at all. An apartment building on a lot with 3 stories or 30, same rooftop area. Terrible economics.
And electricity is fungible! Make it over there; use it over here. Almost free. Certainly cheaper than struggling to mount something delicate in the hardest place you can find.
That might be true in some places, but in Europe for example there really isn't that much room left. And moving large quantities of electricity from a desert to a place where people actually use it is also a challenge
High voltage transmission losses can be low, <3%. I have seen previous reports that 5-7% of all electricity is lost to transmission. For a backbone (highly maintained) electrical network, I think that would be fairly marginal cost vs everything else involved in the calculation.
There are plenty of cities near the desert to suck up the power without ultra high power transmission. Like phoenix, Vegas, LA…I’m guessing all those opportunities will be soaked up before they start putting them in them in the middle of nowhere.
This can make sense to do, but it ends up being a lot less cost effective than utility scale solar.
A friend of mine lives off grid in Mexico, and he got double duty out of his solar array by making it a big carport and workshop area. So yeah that totally works.
But, if you're going to invest $X in solar, it's better to spend it on utility scale stuff than even commercial versions of covering parking lots. This is because the utility scale operation better amortizes the equipment needed to tie into the grid, as well as operationally will keep the panels clean and working at peak efficiency.
Because on the ground you have have 5 hecrates of solar panels accessible by any joe for repairs and inspection, the same panels on the roof require specialists to climb and inspect, and they are now spread across roofs of 10 different buildings, making maintenance a nightmare
The typical Home Depot store is 105,000 sq feet, which is about 1 hectare. These tend to exist in the same general area as other big box stores and similar huge flat roofed buildings. Those are much closer to where a bunch of electricity is used than the undeveloped or farm land just outside of the burbs.
Add in covered parking lots and distributed batteries (dedicated batteries, cars, etc.) and I bet that we would reduce the need for building even more high voltage lines across the countryside.
We should be looking for ways to generate and store electricity close to where it is needed where we have already destroyed nature.
Do you mean that you can't meet 100% of your demands, or it can't be done for some other reason?
You could reduce, but not eliminate, the demand for purchased energy. Would that be unacceptable? Is there not a net metering programme there?
For me the big deal is usually demonstrating payback. I'm in British Columbia and my solar experience is only with single family homes; on and off grid.
There was no big cost analysis with off grid homes. You need power, or you don't. It's just another category in the budget and the cost decisions are about balancing desires and cost.
With grid-connected homes, we don't even try to sell it now.
Nearly all our customers have mortgages to pay for their new house and factoring in the interest paid makes it much less attractive.
A few years ago, low interest rates and high energy costs made it an easier sale. If you were in the position of having money in the bank, you could get a better return on that money by upgrading your home to save energy. Of course it could only scale as large as the cost of improvements.
Even then, a lot of homeowners didn't intend to own the home long enough to realize the returns, and I don't think small solar systems improve resale value. The feeling in the office is that if you're planning to resell, the money is better spent on the kitchen.
> Even then, a lot of homeowners didn't intend to own the home long enough to realize the returns, and I don't think small solar systems improve resale value. The feeling in the office is that if you're planning to resell, the money is better spent on the kitchen.
Not at today's power prices. A typical kitchen will easily cost as much or more than solar and solar ROI is about 20 to 25% right now, no kitchen will come even close to adding that kind of value to a house. If you can afford to do both, do both, but if you have to choose solar is #1 from an investment perspective (assuming you already have a kitchen...).
That's a nice return. Where I am (BC) we can do net metering but no longer get paid the surplus and I think our power costs are at the lower end of things.
Being in a rain forest doesn't help. Don't get me wrong, the summers are as bright as anywhere else, but the cloudy winters are brutal if you want sunshine.
If it's financed with a mortgage that's another thing to consider.
I just don't ever hear solar come up in conversations about resale. I've heard a couple Realtors mention that energy efficient design is something coming up most often. The big questions are still about the area and how many bed/bath rooms there are.
>(assuming you already have a kitchen...).
You can always get a second kitchen....a summer kitchen.
Yes the first step should be to cover every rooftop and parking. I think a law exist in some states that new construction has to have solar panels on. The law should be passed everywhere.
If land cover is the issue, isn't this a great use case for the airship tech that refuses to die? No land issues, no roof issues, relatively clean area, movable according to weather.. It would be crazy expensive, but airships are keep getting invested in anyway, so why not try adding solar?
Yes I can, I am planning a write up on the current installation.
As for the support structure: the ones on the flat roofs are part homebrew and part standard components, the ones on the slanted roof are on a standard off-the-shelf support.
I'm not agile enough any more to work on a roof so I had the slanted roof done, the other part I did myself.
Another advantage of flat: when angled panels are placed wide enough to not shade each other at noon they will at all other times of the day allow light to hit the ground (and it gets worse with seasons, far worse with 2d tracking). That's good when you want some agrovoltaic dual use, but not good when you want to maximise electricity from a given acreage. Only a flat layout will at any time of day and season collect 100% of the light that would hit a given ground area.
A larger area per panel, sure. But not a larger area per ground area, if you look at a larger installation than a single module (or a single row of modules)
Yes and no, yes, all the light will initially be captured but if the angle is off then a part will be reflected and if the angle is off > 45 degrees then most of it will be reflected.
Surface reflectivity can be an issue, that's true. And the numbers aren't as easily compared as the simple geometry of casting shadows. And I assume that there must be large differences between different module types?
The big difference is the kind of glass and coatings used, this can make a few % difference at the same angle of incidence. Typically the yield below a 45 degree mismatch is the maximum panel yield x cosine(angle of incidence) x transmissions (anywhere from 90 to 95% depending on coating and base material). Beyond 45 degree mismatch there is a sharp drop off.
Certainly a topic where it's impossible to judge without knowing actual curves. Even looking at actual panels (without measuring output) you'd be prone to misjudge because some that look promisingly low in terms of specular reflection might pay for it with higher diffuse which won't notice as long as it's not particularly bright.
That leaves armchair-level pondering to theoreticals: is the perfect "any angle" surface even physically possible or are there physical limits that only leave tradeoffs?
And another aspect I don't know: do the cells mind? Does that "punch an electron" principle still work out when photons come in almost parallel to the electrodes? (in practical terms: if we compensated the lower effective cross section and reflectivity with higher light intensity, would we still get the same voltage?) When I was a kid I had a miniature cell in an experiment kit that had a deep plastic top layer with angled prism structures under the surface almost like those of a retro-reflector and I always wondered why it would have that. Was it because the cell could only collect from photons coming in almost perpendicular, and the job of the plastic structure was to make sure that there would always be some photons making the angle threshold (certainly by sacrificing a huge amount of power in the well-aimed case)
This all almost sounds like an argument for heliostats (which get the best yield per module surface, but the worst yield per acre), and which would be a perfect match for agrivoltaics. But that's an approach that hinges entirely on the cost and (far more importantly, at scale) resource use of the mechanical structures required. Which is a mechanical engineering problem that you'd have no problem explaining to a victorian era engineer. Genius "inventors" to the rescue?
I have 26 panels set up like that of two different types and the figures pretty much match that formula.
I've used two heliostats in the past (see other comment in this thread) and on a $/Watt basis you're better off putting them flat, regardless of the perceived advantages, after all is said and done you will have more power, be out less money and have a more reliable system.
That possible heliostat future I keep bringing up wouldn't be about $/Watt (that was an argument for helostat back when modules were much more expensive, but certainly isn't the case anyone), but about finding a sweet spot in agrivoltaics between energy and nutrient harvest: Watts per impact on farming. Or more specifically, electricity dollars per impact on farming. Because when there is a large installed base of photovoltaics, watts at noon won't be worth much compared to watts at deeper sun hours. And for the same amount of off-noon watts, a heliostat setup would cause less shading to the plants below than any other setup. And as a bonus benefit, the east/west spacing inherent to heliostat installations would give a nice distribution of shading, at least nicer than with fixed east/west lines. I believe that the advantages are quite clear, but of course only if the mechanical parts can be cheap enough (in terms of resource use). Flat north/south lines that only pivot east/west would surely be a sweet spot, up to a certain latitude.
The amount of land required to supply ample energy to some random region (bar Switzerland) is usually a small fraction of what is dedicated to agriculture / barren land.
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.
Harkonnen had a long-term project to make dynamic shadows that would change throughout the day, which would result in the solar panels being fully lit for at least a moment at noonish, but I got the impression that side-project was eventually canned due to, uhm, personnel issues.
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.
> Less cost per install means more money for acres.
Less cost smells like cutting corners in this case. Kinda of like saying concrete and rebar are expensive and you could build a bigger house without them.
Is that true though?
Flat panels may be good enough but slapping such a high tech piece of equipment on the groud sounds suspiciously too good to be true. I suspect the cost per panel to be insanely high if not upfront then in maintenance.
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?
First, they are banking on the fact that solar doesn't need a lot of repair and maintenance in general, and their design decreases some of the stresses that racked solar panels encounter. I imagine they are also over-sizing the system, and adding remote disconnects so they can disable a certain number of panels and still meet the contract.
And then when repair is needed, they just walk on it[1]. Seriously. I'm very curious as to what these pads they mention are like - big foam snow shoes, or walkways they rollout along a seam?
Oh, that's interesting. And I guess if they do manage to break a few panels, they can be replaced cheaply. Its probably still cheaper than dealing with racking.
They are ridiculously strong. I've had a set of 8 on a tracker be blown over by the wind (in spite of ample foundation according to the people that sold me the gear), land on the edge and not get damaged at all. That was a pretty heavy impact too, the whole thing was 30 cm into the ground.
I assume they need to worry about scratches. An XXXXXL clean room bootie wouldn't work because it would pick up sand and grit as you walk across the panels.
Re cleaning, they have a cute little robot that you can see on this page: https://www.erthos.com/energyservices It's also visible in the photo in the article.
I wonder what happens after a major rain though. I suppose the panels are weatherproof. But they lie directly on the ground, and I did not notice any mention of a drainage system. The panels will eventually sag under load from rainwater, preventing it from flowing off them.
They mention that their installation can withstand a hurricane. I understand how it works for the wind load, but every hurricane I witnessed brought a lot of rain.
EDIT: Apparently they embrace flooding, and say that their panels and connectors can withstand being submerged in water. That's the spirit.
The image also seems to show water damage in the corner of the closest panel.
At a guess, they target areas without heavy rainfall, and fast draining soils. I didn’t see any drainage works in the video https://vimeo.com/556421759, nor did my google-fu help me find anything where they address the issue.
How do the installations perform in the rain and snow? “Our hydrology report proves that an Erthos plant is almost the same as native soils with respect to accumulated water depth and velocity in rainstorms. All of our designs include professional civil design that includes water runoff management and containment basins as per the jurisdiction’s application of building code and other local requirements.”
What about flooding? “The glass/ glass modules and the connectors we specify are all rated for submersion, so flooding is not a catastrophic event in case it does occur.”
Blemishes on solar panels aren't necessarily bad or have a huge effect on generation or durability. These could also be previously used panels in the image, which are often sold at enough of a discount to offset the loss in power generation.
Thanks for posting that! Made me realize that when all the panels are laid over a huge area in essentially the same plane that it must be so much easier and cheaper to clean. Just put this robot on it and let it go, roomba-style (OK, not exactly roomba-style of going over the same spot 50 times, but you get the idea). Seems like it would be a lot cheaper than what would be needed to keep rack-mounted systems clean.
maybe use a little potassium carbonate to convert the uric acid in the bird shit to dipotassium urate, thus increasing its water-solubility 300×, and follow up with a strong buffer that's mildly acidic like monopotassium phosphate to prevent any stray residues from the solution from causing alkali corrosion of the glass when it dries
probably there are a lot of possibilities you haven't tried on your windshield yet
My point only concerned the robot. Other solar installations won't have a tiny self-driving Zamboni that's ineffective at cleaning bird poo and is bound to be stolen. They use renewable and cost-effective elbow grease instead.
The solution here seems to create a zone that is completely inhospitable to the ecosystem that should exist in that spot. In the picture in the article, the bird poop will be highly concentrated in the forest area that is nearby. While there will be some birds that fly over this dead zone, I bet the droppings will be minimal.
Edit: The article mentions a 100 MW installation. At 2.5 acres per MW, that is 40 acres or 0.25 miles x 0.25 miles. While there will certainly be some service roads, no matter what the ecosystem was before, it will be covered with something that doesn't support plant material, insects, etc. that may be consumed directly by birds or the small animals upon which birds prey. Birds will find a more hospitable place to poop.
I can't see how bird poo could be a problem here: there's no food, nesting site, nor high spot to hang out anywhere near it. Theft could be a problem, though I'd assume they'd have some sort of protection hidden on it.
It appears too small to have enough mass to use gravity to be able to do a thing with dried guano. Also, because it has wheels, it gives me the impression that it moves along and does whatever cleaning its capable of as it goes rather than lingering anywhere to thoroughly clean one spot.
> they could have a pressure washer inside that thing
Thanks, I was wondering how they were going to keep it clean, and the linked article doesn't have the word "clean" in it at all, so it could be improved by discussing more about that. I also see now that the little robot is in the pic in the linked article too.
Install cost is ~50-75% the total cost of the system. If you can bring install cost down your tolerance for panel failure can be quite high while still having a better roi
I would have expected it to be like agricultural products -- rows of corn with spaces between rows, so you could access the interior without stepping over the outer panels.
3 meter high frames with the panels on top, wide row spacing (about 10x), and crops in the ground. Minimal harvest yield loss (sometimes even improvement, as the shading reduces stress on the plants), and selling power from the same land. It could be marketed as "zero land needed" PV power.
With Erthos's on-ground panels, a robot with fat soft tires rolls over the panels. No walking needed.
I assume the conductors will be direct burial cable or single conductors run inside PVC conduit, just like any other outdoor electrical installation. The connectors and junction boxes are probably IP68 rated to handle flooding.
Agreed. The dust is likely to stay there and not blow off and also type of installation does not allow of undergrowth much less dual use of land (parking lot or other potential land use).
I have a similar setup and rain takes care of the dust. A bigger problem is the leaves and bird droppings that get stuck, even that gets dealt with by the rain (eventually) but it has to be a pretty good downpour for that to wash off. Fortunately here in NL we have no shortage of those.
Land costs are still generally irrelevant for solar as in well under 5% the cost of this install and you can recover that after at the end of the panel lifespan.
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:
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:
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:
Generally if you're grid-tied your setup needs to be approved by the power company and they have a surprising amount of say in what specific equipment by what vendors you can use. If you watch his videos on his specific home setup, he has a separate grid-tied system and his testing system and they don't touch. He even remarks that some of them wouldn't have been his choice.
I watched a video from the 8-bit guy about tying solar panels to the grid. He said that if you do that, your power fails at the same time as the grid's power, so you don't get any backup electrical power. For that reason, he recommended against tying your solar to the grid.
It’s completely possible to have backup power and be grid-tied. The main issue is your panels feeding the grid during a blackout, which can be dangerous for people trying to fix stuff. All that’s required (requirements will vary widely per region) is an automatic disconnect that disconnects your setup from the grid when the grid goes down. For example, Tthe new Enphase EQ8 micro inverters have an optional controller to do this. AFAIK the Enphase systems are the best selling micro inverter systems out there so new installations should have no issues being self sufficient during outages.
Anything that can be legally connected to grid has to be certified to stop supply back to grid in case of blackout. Is there any region where this isn't the case? I doubt it.
Temporary solar panels are interesting to me - where I live there's a large chunk of the year where weekly solar output plummets. Stacking them in the garage overwinter is appealing, I might try this soon.
Meh. Throw a moving blanket over it and bungee it on. Could weld up a cart to roll them all at once sideways. Could use spring casters like for gates as a suspension. Or hold them in place with low durometer rubber. Or both. Probably want them sideways for footprint in my garage anyhow. It would be fun to optimize the process more each year.
My property is very small and I currently use that back space to park my nice car during the winter so the daily is in the garage and the front driveway is easier to plow. Sounds weird to me typing it out, but I promise this arrangement makes more sense when living here.
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:
I bought 20kw of solar from China that arrived this year, the quote I got for installation was about what I paid for the whole system. I'm thinking about just installing it myself.
I think including shipping and import fees it was about $26k. I looked at getting panels directly from a supplier, but it's very difficult to figure out which companies actually manufacture things. I ended up buying from one of the many companies that buys components and packages them together into complete systems.
As a probably silly idea, I wonder if the panels could each sit on an inflated/foam and buoyant pad, be chained by flexible cables and then be pinned to the ground at intervals. That might give it some flexibility in the event of flooding.
Both talk a lot about time and material saved, which I guess is also important, but neither gives any figures as to how much efficiency will be lost.
Isn't the whole point of trackers and optimal angle calculations that regular panels are kinda crap if not pointed directly at a 90 degree angle to incoming light? If I recall right some installations have almost got half more output by going from fixed to trackers. This would be even worse than fixed at the optimal angle...
When I was installing my 6.6kW array, I was pissed that I got the southern orientation of 1 half of the array off by a few degrees. Turns out I was going to lose about 1% of production. Out of interest, I looked up what the drop would be if I had actually installed them all, at a 30 degree slope, facing north.
It's all about the cosine of the angle between the panel's normal and the direction toward the sun. If that angle is 0, the cosine is 1 and you get maximum efficiency.
The error angle has to increase to 60 degrees before the cosine decreases to 0.5. Meaning you can tolerate a lot of slop before you lose half your output.
Trackers were a big deal when PV panels were 10x or 20x more expensive than they are now. Back then every bit of added efficiency was worthwhile. Not so much now.
Edit: It's more complicated than this: You have to compute two cosines (azimuth and elevation) and average over both days and seasons, but the basic point is still true.
Googling shows gains of 25-35%. Dual tracking adds another 5-10%. I can really see how just placing more of these simple flat ones would be more economical than a complicated racking and tracking system.
Already, 96% of mammal biomass is humans and livestock. No one has the power to stop this process, to do what it would take. Enforcing a strict max-2 child policy on the whole world and/or telling people to live in the pods and eat the bugs. Hopefully, once our civilization goes interplanetary, we can try to restore a bit of what was lost.
Fertility rate is already below replacement for all of the world except sub-Saharan Africa, and it's dropping there too. We're headed for population decline within a century unless something changes dramatically.
Covering the ground with impermeable surfaces isn't great either. (Maybe they have drain holes at regular intervals so that's not as much of a problem?)
I'm guessing they will probably need a tall fence around the outside to keep deer away.
agrivoltaics requires more space between racks to provide sufficient light for the plants to grow. that's neither a good or a bad thing - it's just a statement of fact about the paired compromises that arise from combining PV generation with agriculture. It is still likely a good idea in many places.
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.
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.
Can't tell from their website but I really hope they're not using per-panel "solar inverters" at all. The whole ground-touching array should be DC with no electronics whatsoever (except maybe for diodes, and with no significant shadows they might not even need those).
Any inverters present should be large, few, and in their own weatherproof housings above the ground.
I think per-panel inverters are a stupid idea, especially for large utility-scale installations. Sorry if I misinterpreted your comment and you meant something else.
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
Bizarrely, ants were attracted to our Tesla power connector on our previous car. We googled it and it was a common problem, ants seem to love electricity.
What you lose with Erthos' approach is any possibility of using bifacial panels.
In regions that get snow, bifacial panels (that use light reflected onto the back of the panels as well as light from the front) get a lot better output in the winter, increasing the annual capacity factor and therefor return on investment. (Winter electricity can be more valuable too, in those regions.)
Solar in Texas seems like an obvious win in just about any configuration. But I wonder how this would work at higher northern latitudes in the winter. I suspect efficiency would be pretty bad with a 20 degree incidence.
the unintuitive part is that land is even cheaper than panels, so you'd think that spending more panels to use less land would be a losing proposition
the interesting question is whether the costs of racking, grading, cleaning, repairing, etc., go up or down, and if they go down, whether it's enough of a reduction to make up for the larger amount of solar panels per average watt, as they say it will be
Based on my calculations, at my latitude (40 degrees North), you would need about 16% more panels to generate an equivalent amount of energy per year. This isn't taking into account potential issues with snow buildup (which theoretically would be worse with flat panels) or the effects of cooling (which theoretically could be better due to contact with a thermal sink, the ground), but it's probably pretty close. Even if 20% more panels are required, that means capital costs are superior as long as panel costs are less than 5x racking material and labor costs. Currently panel costs are more like 3x racking costs and will probably continue to decline. Racking costs will probably not go down unless steel prices go down pretty significantly. The only thing that surprises me is that there are not more companies doing this. Perhaps there are factors that neither Erthos nor I am properly considering, but I think this is how most utility solar projects will be done in 5-10 years.
We put in 40 KW and in the racking was a nightmare. The government required soil analysis, reinforced racks, and cement pilings 4 ft deep. Probably could have put in double the panels if we didn't have to deal with the f*** racks
I think this approach has interesting applications for small-scale solar in rural environments if the permitting can be streamlined
steel prices are probably not a significant component of racking prices; scrap steel costs 50¢ a kg
the numbers they gave make the pv module prices seem slightly higher than the cited racking prices (15¢ per watt) but it's a little hard to be sure because of the numerous kinds of watts involved
Everyone is talking about maintenance ITT. Is it that big of a concern? My parents have had solar on their roof for almost 10 years now with zero issues. I imagine newer panels last longer.
So what's the actual maintenance cost? I could imagine it's going to be cheaper to just install new panels every few decades than constantly maintaining the installation to be 100% capacity.
For a grid scale installation, let’s say 5% of panels are dead due to whatever failure. I am not sure the rational response would be to do any maintenance vs installing more capacity. Twenty years later rip out all of the old panels, replace with new. Repeat forever.
> 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.
> 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.
That is not true from my understanding. The increased solar angle of incidence effects how much of the energy reflects back into the sky. Having more panels next to it without a gap won't change that. Yes you can fit more panels in the same area without putting them on an angle but they will be quite a bit less efficient because more light will be reflecting back up per sqft of panel which is what matters cost wise.
Yes, one of the many areas of improvement of PV modules in the last couple of years has been reducing reflections from the surface of the glass and from the glass-cell boundary in panels. Also changed cell technology (n-TOPCon) helps with reflections and recombination within the cells.
it's true that you get 100% of the sunlight that falls on the land, or near enough (albedo is not literally zero at any angle) but you need more solar panels per output watt
it'll be interesting to know if they're derating the nameplate capacity by cos(latitude) as they should be
Their agreements with their local grid operator will specify power delivery. Marketing numbers like an individual panel's nameplate output are not important at utility scale, which this is designed for.
probably the local transmission companies are interested in not only average ouptut but peak output, but also, there were a number of numbers in the article cited as "per watt" which look like they might be talking about peak watts
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.
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.
I think using the dirt that's already there and building the structure with some kind of machine would be cheaper than having someone mounting them on a steel rack. See for instance large potato fields [0]. The point is instead of putting them on flat ground, make the ground have a better shape first.
The racks are really easy, well known technology. That was my point. If you're going to give up the entire reason for laying them flat on the ground, you're going back to the way existing solar farms work, so just use the same proven technology.
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.
They don't look propped at all in the photos. Also I think propping would be hard for the cleaning robot as it looks like is a super simple little robot with small wheels and just rolls straightened over them.
Yah its probably a case that designing a vacmop style device (possibly purchased off the open market?) and having it drive around on a flat surface is both cheaper and keeps the panels cleaner than a custom bot that doesn't clean as frequently because it costs to much.
My question is whether sitting on the ground itself causes problems with efficiency due to the panels getting hotter than they would with some airflow under them.
According to the research on their site, ground mount solar has better heat dissipation than roof mount solar, and isn't that far behind racked systems, so it's not really a concern. The ground ends up acting as a heat sink.
(Modern utility scale PV installations are already using automated cleaning solutions).
It is much better from POV of the cleaning robot maneuvering requirements. It's also much better in terms of single robot can access the entire installation.
But it's worse in terms of how much distance the dust should be pushed before it's off panel (as I don't see any gaps there)
Service trade-off seems pretty marginal. They say the panels aren't tied down to the ground in any way, so you might be able to just pick one up and disconnect it
Yeah I don't understand people getting hung up on efficiency with solar panels. The sun is always up there producing the exact same amount of energy with zero input from us. We're not doing any work to get the input energy for the panels.
Efficiency would only matter if we'd already covered all the available area with panels and needed to start replacing existing ones, otherwise $/watt hour is the only metric that's important.
until only a few years ago solar panels were enormously more expensive per square meter and per peak watt, so doing things to increase their efficiency was a great way to reduce $/watt hour
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.
The amount of power landing on an acre is fixed, what you can achieve by tilting is having less solar panel surface area per ground cover area. If solar panels are cheaper than the mounting hardware (wow) then there is no reason not to let them lie flat on the ground (it's not as if the racks were holding them above tree shadows, or anything).
This is a great way of thinking about it, but don't you lose a bit more due to increased reflection from the glass surface at low incident angles? Probably not enough to make a difference a low latitudes in the summer, but at high latitudes in the winter I think it might be a significant difference: https://en.wikipedia.org/wiki/Fresnel_equations#/media/File:...
Partially answering myself, 'sacred_numbers' posted a link elsewhere in this thread that suggests this effect might be quite small: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6611928/. The paper concludes that for a cell with a good Anti-Reflective Coating (ARC), the reduction in efficiency due to reflection at a 60 deg incidence is only 2%.
On the other hand, the incidence for a flat mounted panel beyond 37 degrees of latitude on the winter solstice is greater than 60 degrees, and it's not clear (to me at least) how well the ARC on an average panel will continue working after years of outdoor usage. My guess is reflection is probably a real issue, but not a stopper unless one is already in a marginal situation.
I'm at 54N and my output has been 0 for the past month as we've had a lot of snowfall. My panels are at 20 degrees, so even in the few sunny days we've had it's not been enough to melt the snow. A steeper angle probably would have cleared it a few times.
Usually the beginning of the year has more sun but it's colder, so I'll see what happens then.
The solar radiation wattage per unit of surface area is dependent on the angle that surface is to the sun. The angle is dependent on the season and time of day, so the amount of power is not fixed.
What the comment wanted to say is that the power per unit of ground surface area is fixed for a given location and time, i.e. it does not matter [1] whether you cover a given area with panels angled towards the sun or lying flat on the ground, at least if one only looks at the available power. There is of course a difference in the solar panel area required to cover a given area of ground surface - solar panels lying flat on the ground will obviously have to have the same area as the ground surface area while panels angled towards the sun will only require a fraction of the ground surface area equal to the sine of the angle of the sun above the horizon.
[1] For a sufficiently large area so that effects on the edge are negligible.
You could write a few pages of all the things that the power available depends on, but you don't need to because it's fixed relative to the variables under consideration.
Per unit of panel surface area, not per unit of land area. If the sun is coming in at an angle, you'd be able to collect all that's available with less panel area than total land area by angling them (or equivalently, in this new configuration you need more panel area than you otherwise would), but in their estimation, it's cheaper to just get more panels than it is to buy and install racks.
>The solar radiation wattage per unit of surface area is dependent on the angle that surface is to the sun.
A tilted solar panel casts a shadow that is bigger than its actual area. Mounting the panel flush to the ground means it casts a shadow exactly equal to its area.
The shadow represents the captured sunlight so the first panel covers more surface area than the second panel, which allows you to reduce the number of panels to cover the same amount of surface area. The entire point of this article is that you can just put the saved costs into buying more solar panels.
Used solar panels are very cheap but usually only the solar panels are replaced and the mounts are kept and fitted with new panels. So for companies that want to use used panels their primary cost is actually in the mounting hardware and not the panels.
> If solar panels are cheaper than the mounting hardware (wow)
I'm surprised this surprises people... Every electronics hobbyist knows that electronics are cheap as dirt while any kind of box, mount, rail or whatever is BY REALLY FAR the most expensive part of a project, even when buying massivly mass produced cheap Chinese junk.
You are surprised that this surprised people because electronic hobbyists know this? Most people are not electronic hobbyists so this should probably not surprise you
I just find it interesting, the difference different perspectives can make, especially on a website where people are often bikeshedding things they have no experience with.
Texas is pretty far south. If you use https://pvwatts.nrel.gov/pvwatts.php there is about a 9% increase in total output over the year for optimal tilt(27 vs 0) but then you also need to space modules.
There is hourly data if you are interested but even Jan 1 the panels produce for ~7-8 hours. The 3 hour around noon it's about 1/2 the output for the day (for Jan 1).
> you get a a lot around noon and then very little.
That's a little harsher than reality. You get a very pretty bell curve. I have a flat panel on the roof of my RV and I track the output over time. I'm not 100% how much of the loss in output is because the incidence to the panel is changing, or because the light from the sun is going through more atmosphere. Probably a little of both, but in any case the panel is still plenty useful even when not pointed directly at the sun.
With tilted modules, you'd normally space them out quite a bit so the shadows of one aren't falling on the module next to it. If they're all flat, that's not a problem so you can space them closer. So, it makes sense that they'd get more power per acre than the conventional approach -- the panels are individually less efficient, but there's a lot more total solar panel area per acre.
That might not always be a good tradeoff, but maybe at least some of the time it is.
I expect that they are getting lower output per acre, but in places where land is cheap and as solar panels continue to get cheaper, the money saved on building the support structures could be worth those losses.
They don't claim to outperform fixed-tile or SAT on that KPI. They claim to reduce upfront cost of installation, construction time, and general project risk.
Seems lying them flat also makes their cleaning robot able to easily maneuver, meaning they don't need to leave any space in between panels for humans to perform maintenance. Pros: reduces land usage as you mention, but also less humans needed for maintenance.
The article claims it's much higher output per acre:
> conventional solar technologies, which typically require five to 10 acres of land per megawatt of capacity. Erthos claims that its mounting scheme requires less than 2.5 acres per megawatt.
They claim the power per acre is 4x higher than tilted panels. Seems like a stretch, but I don't know how bad the density is in tilted installations. I guess I have seen some where you can drive between rows
Density in tilted installations is quite bad. If you want to capture morning and evening sun at an optimal angle you have to space the panels out a lot, like 5-10 panel heights. You can have them closer, but then you get shading, which defeats the purpose of tilting the panels.
> 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?
I suppose if we're charitable, maybe "From 2010 to 2021" is programmer style [2010, 2021), i.e., ending at 1 Jan 2021. Then all of 2021 & 2022 form "a couple of years". (The book is more or less closed on 2022. Given that my "2 day shipping" from cyber Monday took 8 days, I'm not holding my breath on "the supply chain" fixing itself prior to people giving it up for the holiday retreat.)
The two time periods you have quoted are not necessarily non-overlapping time periods. Nothing from your quote implies that the couple of years begins at 2021.
Falling between two dates does not imply that it fell uniformly or that it fell for every year between those two dates.
I think "couple" is pretty typically accepted as being "two", at least in most US settings; I can't speak for international variations. In my home area of central Pennsylvania "couple" is a more general, meaning anywhere between 2 and 4, but I think that usage is rather the exception than the rule.
Nonetheless, we can probably give them a pass for saying "couple" instead of "nearly three" since January 2020.
Also from central PA: my dad and I had this discussion years ago and he argued the syllables made the count: (1)A (2)Few and (1)A (2)Coup (3)le. I was in the other camp that a couple is two (husband and wife) and a few was much more loose on definition (2-5).
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!
In this case, I think the earth acts as a heat sink. Or so they claim on their website (https://www.erthos.com)
Neither their press release nor the article says where exactly in Texas it is, but I bet it would make sense to put it in the desert where it gets cold at night.
With the ground covered, evaporation is greatly reduced, so the soil stays moist. Water is a good heat conductor.
Having the underlayer for your roof solar tiles be full of water is considered undesirable by most permit-issuing authorities, so roof tiles must use air cooling.
Economies of scale, better energy efficiency in smelting polysilicon and making ingots of purified silicon, better ingot quality, more wafers per ingot, more usable cells per wafer, new cell manufacturing that reduces the number of steps and produces better cells, bigger panels so there is less dead area around the edges, better glass that is stronger so can be thinner and less reflective so the panels perform better,optimized wiring inside the panels, better cheaper wiring connectors...
A zillion tiny improvements, at every stage in the manufacturing process.
The next quantum leap is coming soon: two-layer cells with an efficiency jump from the current 22% to over 30% sunlight-electricity.
The big change in recent years is the explosion of perovskite-family cell materials. There's a huge variety of perovskite materials offering tunable band gaps and they can be processed at low temperature, so they can be used as top cells over silicon. That promises a big cost reduction from conventional multijunction cells built with III-V compound semiconductors on germanium [1].
There are a few problems so far:
- The perovskite materials containing organic moieties tend to be sensitive to degradation by moisture and/or oxygen. They need to demonstrate 20+ years of service life to match silicon.
- The purely inorganic materials like cesium lead iodide are more stable but have yet to attain high cell efficiency.
- There is no proven high-volume way to deposit the thin films of perovskite materials, which have different handling characteristics than anything previously used in solar manufacturing.
I would say there's a good chance of silicon/perovskite tandem cells taking off this decade but it's not yet a sure thing.
i'd say they need to demonstrate 50+ years of service life to match silicon, but at 10+ years they'd be marketable at conventional utility discount rates, and beyond 20 years the npv doesn't change noticeably
it'll sure be interesting to see what happens here, but it's going to be really tough to match silicon's cost per watt, much less beat it, unless you can dispense with the glass or something
while they are indeed rated for 20–25 years, as you know, in silicon panels most of the degradation happens in the first couple of years; additional degradation in the following 30–25 years is measurable but fairly minimal
as i understand it, panels are rated for 20 years not because they need to be replaced then but because 30 years ago nobody knew what would happen over that time, and also manufacturers didn't want to set themselves up for unlimited liability
usually it's more advantageous to add more panels than to replace the existing ones at that point, though rooftop installations are often an exception due to the extreme space limitations
i think if you sold a perovskite hybrid panel that cost half as much per watt as existing silicon panels, but degraded down to 70% of its rated capacity at 10 years and rapidly down to 50% after that, i think it would still sell in a lot of markets
Yes, high-efficiency cells have been around for a long time for cost-no-object applications, mainly space.
What's changing is commercialization. Two or three of the big Chinese manufacturers have pilot projects going for two-layer cells. Of the order of 10 MWe, that sort of size. (I can't remember which companies, sorry; it was a few weeks ago I read about this. Probably at least one of Jinko, JA Solar, or LONGi is in there, as well as one or two of the second tier.) Also in the West there are a few startups working on two-layer cells, either perovskite on silicon or perovskite on perovskite.
(Perovskites are more easily "tunable" in terms of which frequencies of light they absorb, apparently--that's one of their attractions.)
Usually the expected life is ~30 years. They may last longer. I do wonder if pests and moisture will be early failure causes in this configuration though. Then again, if it saves enough money, maybe that doesn't matter.
TBH, the part that lasts the least amount of time is often the inverter.
You don't even really need to tile your yard with solar panels. Depending on location, you could be self-sufficient(ish) with 10 kW of solar, 25kWh of batteries, and a 10 kVA generator for cloudy weeks.
Total cost is around $40k.
However, unless you're rural or somewhere with poor grid reliability it's probably not worth the expense of being off-grid. Generally speaking, due to generous feed-in tariffs you would be (financially) better off staying connected to the grid than spending the additional money required to handle periods of cloudy weather.
My co-worker did just that, but at a much higher latitude(49°) than Texas - he couldn't be arsed with building racks for the panels himself and having people do it for him would cost too much in his view.
While the panels are indeed cheap this, along with the DIY wood gas combined heat and power generator, are measures taken for energy security, not profit.
Yeah, nah, these are for utility scale PV plants, sorry.
In a few years, you might be able to buy a roll of PV film in a box and unroll it in your yard. The box it comes in would have all the gubbins to connect up to the house.
Flat makes more sense the closer the panels are to the equator. At high latitudes, the more atmo the solar must penetrate -and- the less efficient a flat panel is. Some good diagrams here: [https://www.altenergymag.com/article/2005/08/solar-energy-po...]
This is true, but even then the area required is much larger than if you were to simply stack them side-by-side. It helps if the whole surface is inclined as well, ideally on the Northern hemisphere a South facing roof.
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!
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.
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.
Sounds great, but the land underneath is absolutely killed as if it were paved over, no grass, ground cover, crops or anything. That said, it seems to be less than half the amount of land.
Nevertheless, it seems that the innovative German installation method of using vertical panels in between agricultural rows is better [0].
No aggregate is laid down, nor is asphalt put on top of the aggregate. No toxins are put in, nor does the topsoil need to be scraped off.
End-of-life reinstatement of the land shouldn't take more than ten years of seeding a sequence of plants that specialize in colonizing and re-aerating bare compacted soil, and revitalizing the soil ecology. (Weeds.)
Yes, EOL recovery could be quicker than if it were paved (assuming that paving strips the topsoil completely and not just paves over it) but much slower than if it remained growing all the time.
The problem is that soil is not just inert, and completely covering it like that kills the entire microbiome — the fungi, bacteria, and myriad of multicellular micro-critters that make the soil good for plant growth will be long gone when they take up the panels.
Who cares? Honestly, a hundred acres of scrubland turned into green energy is a steal compared to everything else we do on this planet for food, energy, and material
Sure, on a scale of comparative bad things, e.g., vs strip mining...
But if you don't have to kill the entire soil microbiome, why do it? Just questioning whether this is as good as vertical panels + farming.
I agree, if it really is nearly devoid of vegetation, it seems better to use the least possible amount land and also not use the metals for the racking.
Maybe I'm just being pessimistic, but the failure mechanism is the erosion of the underlying denuded ground in a large storm to the point that the underlying structure moves.
I don’t think that’s being too pessimistic. I didn’t think about that. The solution would be some sort of concrete footing or something—but I’m sure that is more expensive than just mounting these panels in the air.
It looks like they're probably targeting places where huge rain isn't an issue and it looks like they do some site work to raise it up a bit? Theres another photo here :
My panels were cheeper than the mounting equipment... If I had tons of space I would scale up panels and put them on the ground instead of mounting/tilting gear.
Will be interesting to see how this interacts with the ecology. Normally a complete shading like this would kill off everything underneath, which will mean it’ll produce loose soil and dust. In some hot environments it may produce a bunch of condensation overnight and if the panels aren’t raked at all that’ll be a challenge to deal with.
Operation. Any time you profoundly change the terrain (soil,water,sunlight) you catastrophically upset the ecosystem. It may come to another equilibrium over time, but that's just nature doing its good thing. There's a finite capacity for that etc.
Most ground mount solar projects have a base flood elevation, under which the panels will be inundated with water, not to mention, moved at least once a year. A rack-less mounting solution might work in some locations, but very few.
Does solar panel efficiency get affected much angle of incidence? I.e. are you losing out on any power by using large panels to cover the ground instead of having smaller panels that are steered to cover the ground in shadow?
Is that really a startup? It seems pretty straightforward, no uncertainties. Or there is some legal \ approval challenges I'm not aware of? That solar panel Roomba seems to be the only unique thing about the project.
Interesting idea. I've been toying with the idea of doing a ground mount install at home, but maybe I should try this instead to get more density. I love toys...
In the long run, these should not be paving over natural habitats. There are plenty of life-devoid environments outside of Earth where these can be positioned.
If they lie on a flat, impact absorbing material (i.e. sand), then hail would do less damage than for standing panels. One could walk on them. If, as you propose, put flat rigid cement below, I'd thing you could drive on them.
From the land topography fitting perspective, it's too bad panels are triangular. Then one could essentially create a triangular mesh overlay of panels over all kinds of uneven terrain.
- easier maintainance, since you can clean panels with a roomba-like rover instead of walking down with a hose. Replacements don't require ladders and cranes, since panels can be smaller without requiring more support
-more heat may be irrelevant and anyway it's speculative
-no plants growing under them to constantly be trimming
"Erthos claims it can build a solar power plant in half the time on one-third of the land" sounds like red flag to me. They have not tripled the solar flux or the efficiency of their solar panels.
On most solar farms, the panels only cover about a sixth of the land area, or less. The rest is taken up with accessways between the rows of panels, and roads around the outside. Check out some photos, for example https://energy-cc.co.uk/wp-content/uploads/2020/09/Benbole-S...
The reason the rows are widely spaced is to minimize shading by a row of the one behind, when the sun is low in the sky.
With the panels being flat on the ground there is no shading problem. Laying them side by side eliminates the gaps and they plug together so there is no wiring to do. Omitting the racking eliminates its cost, the time to install it, and the wiring between rows.
A SIXTH? I don't see how that can be necessary. They might use that much land because it's worthless desert or something like that.
Where I am there is not exactly a solar farm, but there is a maybe half megawatt array on a flat canopy over a parking lot. This is in an area of expensive real estate, and there is almost no wasted space.
As for spacing to avoid shading when the sun is low, obviously that is an optimization problem and in all likelihood they have worked it out. Don't forget that when the sun is low, the flat array produces almost no power.
It's hilarious how some commenters are concerned about bird poop, when fact of the matter, birds die by the thousands each year in California alone either mistaking solar farms for lakes and attempting water landings, or by dying by fire in panels' collective solar flux. This pond will be covered in carcasses.
This type of solar farm is doomed to spend that money saved in either prevention and/or cleanup and repair.
> by dying by fire in panels' collective solar flux
That is exclusive to concentrated solar[1], which is essentially obsolete.
> birds die by the thousands each year
A BILLION birds die each year from flying into windows in the US[2]. In fact the majority of birds killed at Ivanpah are killed by flying into the tower, not from being cooked.
> This pond will be covered in carcasses.
Nope! If a bird tries to fly into a rack-mounted panel, it'll probably die, because it's basically flying directly into the surface. If it tries to land on a FLAT panel, it'll be totally fine. Birds don't try landing on water by smashing directly into it.
Also, I have never heard of this "water landing" theory, I suspect its bullshit, and I'm very skeptical that there are many birds trying to do water landings in Texas due to the fact that there aren't a whole lotta lakes there because it's Texas.
I do not believe their claimed savings. Steel is a very cheap building material and at the scale of solar farms, the cost should be very low. (As an alternative to stainless steel on the other hand, it may make more sense)
