Solar on Warehouses
environmentamerica.org
environmentamerica.org
https://www.cnbc.com/2022/09/01/amazon-took-solar-rooftops-o...
https://www.cnbc.com/2019/11/05/tesla-and-walmart-settle-ove...
Might have been a Tesla issue in both cases.
Probably a lot easier on the business risk side of things to not have solar on the roof because then the risk for a fire is massively reduced in the first place.
I couldn't find a local solar installer that wanted to use the type of cheap inverters that Tesla wanted to use. My neighbor has to have Tesla come out about once a year to fix issues.
The first is the "solar roof" sort of thing that... we'll see how maintainable it is, but you get to write a properly large check for it, and most of the people I know with it have a couple Powerwalls, and are quite adverse to sharing any sort of actual pricing on it, muttering about "Well, wife acceptance factor" and "But it'll be worth it in power outages..." and such. In other words, almost certainly north of $5/W, and they likely didn't get an itemized invoice of materials/labor/etc.
Tesla also, in some markets, has a "standard solar panel" offering that typically comes in around $2.50/W, give or take, and... well, you get what you pay for, typically. It ranges from "decent and a good deal" to "a hot mess," and you've no idea what you're going to get ahead of time.
... and then there are people like me who have sub-$1.50/W installs (DIY). Mine came in around there, but after figuring out how to optimize it better, a neighbor's build came in around $1/W for a 21kW system.
//EDIT: And, yes, it takes a lot of learning to do. Cross that with the tens of thousands of dollars saved, I think it's well worth the hassle.
Any ideas on what’s driving the cost for installs in the US compared to the EU? I just drove through Florida on vacation and it’s mind boggling to me how few roofs have PV here.
I think it’s linked to installation. Some sources say they didn’t remove them after the fires
That's not a solar problem, that's an installer problem. Clearly you need to have well-qualified people doing and regularly inspecting the installing, just as you would with any type of large-scale infrastructure. Bridges also collapse when they're not inspected, airplanes fall out of the sky.
We put solar on our house and did some pretty rigorous research into the tech precisely because of this concern. After spending many nights/hours understanding the tech in this industry, I can confidently say it matters less about the current generation of solar tech. But, while the degree of quality in solar products exist, what really matters are the contractors that install it. I did not read the articles and I don't want to claim that there's direct causation by contractors, but if I were a betting man, I'd easily put money on the quality of the installation as opposed to the actual tech provided.
Over the long term, it becomes something building codes need to implement, similar to electrical wiring and plumbing standards:
https://www.nrel.gov/state-local-tribal/blog/posts/solar-rea...
https://www.jdsupra.com/legalnews/new-jersey-solar-ready-req...
I know of a city building here where they wanted to install solar and as they got into it realized they would need to hire a steel company to come in and reinforce all the steel roof trusses. That was custom work with welders up on scaffolds and a lot of other work to remove lighting and other fixtures to give them access (and then reinstall it all afterwards). They went ahead with it but with the extra expense it will never be paid back in electrical savings.
* one political party chose to use Solyndra as a cudgel against a reasonable industrial program. I was always dubious that their thin film approach would pan out, and indeed it didn’t which was what killed the company. But admired their basic thesis, which I still think was sound.
Anyway, it's a shame. They were a really neat concept and sidestepped a lot of issues that raise the cost of other systems.
https://renewablesnow.com/news/swedish-online-pharmacy-apote...
One of the best ways to deal with the problem is selling it back to the grid but how that is done vastly changes the payback period. Some states do it as a unit exchange so you sell 1KWh to them then you get that back later when you want it for no cost. Whereas many do a sale price with a price half or worse. Which price you can get for that power and whether its following wholesale (which tends to be peak early evening and be more during the day than night) can drastically change the pay off period.
This is one of the reasons I've argued in favor of "slow, at work charging" as the default for EVs. If you put in a bunch of 240V/16A chargers (3.8kW), as people show up in the 8-9 timeframe, they start charging, and the bulk of the charging happens in the ~10AM-2PM window that's after the morning peak, as solar is ramping up, and before the afternoon cooling/evening peak. You can even restrict the chargers a bit more in the morning if needed until off peak, though I'm not sure this is worth much over just using dumb chargers that are cheap to install. An average 35 miles a day driving (in the US) requires ~10kWh, so you've got a few hours of charging that can swallow an awful lot of power during the time nothing else is using much of it.
It's far better than having to deal with evening and overnight charging.
If you look at grid demand curves, that "late morning, early afternoon" time spot is the mid-day low for most grids. So there's excess capacity anyway, and if you look at the "duck curve" sort of graphs, there's a ton of solar on the grid then anyway. This is only increasing with time. So we may as well make decent use of it.
You could also have some lower power, 1440W charger slots (15A @ 120V) for those who don't need much power - it'll still make up an average day's driving in 8h of charging, but since it's literally the same wiring cost and such to run 120V as 240V, I'm not sure you gain much with it, and it's now perfectly valid for chargers to coordinate regarding total circuit demand anyway.
Might just be me, but I read any comment talking about an ideal future scenario for charging vehicles (if not otherwise qualified) as being for the ideal world where the 99% switched to electric vehicles.
If you're talking about planning for the situation that we have today... that doesn't seem too useful and would be outdated in two-odd years.
Forbidding something is easy... but where the hell will people charge their cars before the cargers are installed? Do you know how long it takes to build a power plant? Do you know how much those things cost? Is there even a company able to build literally billions of charging stations in the next 20 years? 2035 is comming fast... some people have been waiting for a basic build permit for longer than that.
I did... if you want to stop selling gas powered cars by 2035 (or whatever the current cutoff date is), you need pretty much every parking space fitted with a charger in ~2040, since electric should overtake gas powered by then.
High power, low power,... it doesn't matter if you don't have physical chargers installed pretty much everywhere, and enough solar installed to cover the power usage. This is not "distant future", this is less than 20 years away. Suburbia is simple, because most people have an outlet in their garage, but they can only charge at night (no solar), apartment buildings have basically the same issues as office car parks, but with energy needed at night, and if you really want to utilize solar, you need chargers at office car parks too.
I would have thought if the economics were super favourable this would already be happening by now.
To me it -seems- like a great idea but while I'm pretty versed in solar for home scale (diy off-grid setups etc) I have no idea how the numbers bear out for this install size, grid connection, etc.
This is usually under "C&I" (commercial and industrial), as opposed to rooftop or utility scale.
Try Lazard LCoE report, NREL Solar reports, IRENA renewables, or use google.
You're far cheaper on the ground, for a variety of reasons (at least in most areas). A good ground mount install should be able to come in around $1/W, and you'll have a hard time getting roof mount below closer to $1.50 or $2/W installed, and if you get $2/W, you're getting a great deal.
If you're doing the work yourself, ground mount for around $1/W is doable (including the frames), but roof mount I've not been able to get below about $1.25/W, and that's hard - $1.50/W is more typical.
The main difference is that the roof mount system requires rapid shutdown on (in NEC 2017 and later) every panel, and you're limited to 600V (though with rapid shutdown requirements, this is less relevant). For a ground mount system that's isolated away from random people (fenced area), you can run up to 1500VDC to the inverters, and this rather reduces your costs in wiring. You also don't need rapid shutdown, so you can just run strings of panels (20 or 25x 72 cell panels in series, depending on the environment).
Also, if those strings have an arc fault somewhere, you're not going to burn up much that matters for a big ground mount install. You'll cook a couple panels, and that's about it. A fire under the panels on a warehouse is a much bigger deal.
The main problem you run into with warehouses, though, is that there's just no good option for mounting. For a flat roof, they're generally built to exactly the loading requirements for the area. You don't have the spare PSF capacity for a ballasted mount, which means that assuming you've got the weight rating for the panels, you're looking at a lot of roof penetrations on a flat membrane roof to hold stuff down - and the odds of some of those leaking is basically 100%.
Plus it's a royal pain to work on roof mount systems.
utility scale solar on the ground is economically better, if you're looking at "the numbers". but utility scale solar probably means repurposing farmland, because that's the cheapest land that has enough infrastructure built up around it to make a utility install easy. and repurposing farmland to build solar isn't a clear win in terms of overall societal benefit.
Great. Let's start by repurposing the land that grows the corn we turn into ethanol at somewhere around or below unity EROEI, as a political handout to the midwestern states. "Burning a megajoule of diesel, to grow enough corn to make something slightly less than a megajoule of gasoline," is not a winning solution to any problem but "How to best hand money to states that happen to have early Presidential primaries." It's not a bad gig for Iowa (I lived there for a decade), but neither is it a particularly good use of energy, fossil fuels, or money. Let's put solar up there, and work out.
Once we've gotten rid of the ethanol debacle, we can see where things are and discuss from that point, but there is a lot of farmland right now that doesn't grow human or animal food, it grows corn that we process rather inefficiently into ethanol.
i know ethanol farming is a waste, but it's a lot easier to convert a corn field back into a useful farm field before you've built a solar farm on top of it, rather than afterwards
Or you can do agrovoltaics and have both. There's some evidence that low density agrovoltaic setups increase corn yields.
Taking even a fraction of the land used for ethanol and using it for solar would give us enough energy to power the US. And the ethanol business is a complete make work program.
1: https://www.google.com/maps/@34.0297809,-117.9823821,3248m/d...
The best chance for it to be handled some other way is if the warehouse tenant and the solar tenant are one in the same. The landlord will still likely be involved, but chances are the tenant will do the repair.
This will 100% work but we also need battery tech to hit like 250-300 a kwh for storage is my magic number to get a 40-50kwh backup and detach from the grid.
Here you go, a 30kWh 48V battery for $9k ($300/kWh): https://signaturesolar.com/eg4-lifepower4-lithium-batteries-...
I always chuckle when I encounter the sweet summer children that think that battery tech is stagnant...
(Subscription required) https://www.bnef.com/shorts/16235?e=Insight%20Alert:sailthru
It's the sort of thing that sounds obvious if you don't know much about the field, and the more you learn, the more things you realize make it a royal pain in the rear to deal with unless the structure was designed with solar in mind - and even then, it's a pain compared to a ground mount array somewhere close.
For a big membrane roof, you don't want a ton of penetrations - which means ballasted mounts. Except they weigh a lot, and the roof usually isn't built to support them on top of the required weight for rain/snow/etc. So you need to screw the stuff down to the roof, but now you have tons of penetrations in a membrane roof, and if anyone tells you they can do thousands of those without a single leak, they're full of crap.
As I talked about in another comment, you can't just run high voltage DC strings on a roof - you need per panel electronics, so the normal solution is microinverters, but now you're pushing 240V around instead of the 1500V you can run on ground mounted strings, so wiring cost is higher, and Enphase sure makes their money off their handout in the NEC 2017. Reliability of microinverters remains an open question as well. They're not exactly in a good spot for electronics.
You've got open area, you've got a high current interconnection, but the rest of it is just a set of thorny problems that makes it quite a bit more expensive than ground mount.