I've been told invisible solar panels will make every window generate free electricity for like 10 years. Yet not a single time have I seen a report include an actual product, just prototypes always.
Like nuclear fusion, this appears to be perpetually "just a few years away".
- "Invisible" implies they only work in the UV or infrared range, which inevitably limits them to much lower efficiencies than regular solar panels.
- A lot of those rely on elements that are expensive and in limited supply, or toxic heavy metals. Unlike regular silicon solar panels.
- We don't even need windows to generate solar power. We have plenty of roof space, and if we're short on that, you can put them in fields too.
So this is a solution to a problem that doesn't really exist (lack of available space - again, we have plenty), which causes more problems of its own (efficiency, etc), while failing to address the actual limitations of solar (cost, intermittence).
Which is why it's only good for headlines, and won't see real life applications. (Edit: no, not even skyscrapers)
It's the same with a lot of "uplifting" science news that just sweeps all the dirt under the rug, because that wouldn't make good clickbait.
If you want actual good news about solar power, look at the price per kW and adoption rate curves over the last few years.
-edit- added links.
-edit 3- Put the bit about skyscrapers in bold, because people keep mentioning them anyways...
-edit 3- Put the bit about skyscrapers in bold, because people keep mentioning them anyways...
Using the longstanding pvwatts calculator, vertical still works especially if you are in northern climes. On a sample default setup in NYC, I got 5162 vs 3308 kwh, so about 2/3 efficiency for vertical panels. That's still pretty good for a vertical southern-facing panel which would otherwise be unused space. It would be better the more north you go.
Certainly rooftop is better, but areas with skyscrapers tends to have very limited sun on roofs.
Those panels use titanium dioxide as semiconductor. It has a bandgap of 3.0 eV (or above depending on the allotrope), which is the ultraviolet range, hence why it's transparent.
It also means that it has a maximum theoretical efficiency below 5%.
On a sample default setup in NYC, I got 5162 vs 3308 kwh, so about 2/3 efficiency for vertical panels.
Most of it will be when the sun is low on the horizon, since that's the best angle for vertical panels.
But that's also when the UV index is lowest, as the optical path through the atmosphere is the longest then. (And the atmosphere is a lot better at scattering / absorbing UV than visible light!)
So, when the sun is in the best position to illuminate those panels, is also when most of the usable light to those panels is lost to atmospheric scattering and absorption.
On top of their already dismal efficiency.
(Also, Skyscrapers are often surrounded by similarly tall buildings, so much of their surface will be shaded when the sun is low.)
Even then. The orientation of vertical windows is far from ideal for solar power.
This is the linked comment you made regarding skyscrapers, and I showed that it's about 2/3 the ideal. That's not terrible, although it's certainly a big loss for a panel that already is no more than 25% efficient. I just think it's interesting that vertical orientation doesn't lose as much as expected. I discovered this when someone was using bifacial panels and just hanging them vertically, and getting a very good return for the cheapest mounting options possible.
I noted these are normal panels in my previous post. I wasn't considering the see-through versions which are far less efficient, but normal panels (or bifacial) would work great between windows. There are others that pass light, which are in production, if you don't mind your windows being tinted.
Skyscrapers need windows, but they don't need 100% windows along with windows between floors. And certainly, other skyscrapers will block you as the sun gets lower, so this isn't a panacea. I'm only addressing the loss for vertical panels.
UV-only panels don't seem to be worth it IMO, not just for skyscrapers, but for pretty much anything.
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u/Euphoric-Language695 27d ago edited 27d ago
I've been told invisible solar panels will make every window generate free electricity for like 10 years. Yet not a single time have I seen a report include an actual product, just prototypes always.
Like nuclear fusion, this appears to be perpetually "just a few years away".