General > General Technical Chat
Solar Freaking bike parking
switchabl:
Indeed. The economics of solar installations in general are shifting. The costs for the cells/panels themselves have dropped massively but costs for planning and installation (of small-scale systems) have not. 1 It increasingly makes sense to install solar panels in a way that is clearly not ideal from a technical standpoint if there is the possibility to do so cheaply in the course of a project.
Is this the case here? Maybe, maybe not. Sadly for outraged Youtubers everywhere, it's not so easy to tell anymore from just a photo. Durability might still be a deal killer here. On the other hand, they seem to be bolted to the ground in the same way as the bike stands. So the incremental cost to have that done will have been very low.
1 https://www.nrel.gov/news/program/2021/documenting-a-decade-of-cost-declines-for-pv-systems.html
EPAIII:
Three words:
Drill baby, DRILL!
It's all lies to garner votes and "they" know it.
Nominal Animal:
--- Quote from: nctnico on March 05, 2024, 01:19:30 pm ---Typically you come up with very elaborate mathematical proofs of your statements showing you put real thought in your claims. But for things outside your area of expertise, you seem to get caught up in conspiracy theories very easely.
--- End quote ---
No. If you check my history regarding this, I've described my reasoning in the very first thread about these I participated: having the roofs over the stopover points is worth more in comfort than the energy collected any way. Putting the panels on top of those is just extra.
How much do these panels cost? How long will they function? How much electricity will they yield?
Your cost-benefit analysis observes that for a small bike shed, the electricity will not offset the price of the shed. You then make the unrelated leap of faith, and assume that that means putting the panels on the ground must therefore be better. It is not, because the lifetime electricity yield is even smaller fraction of the installation cost, because of the more expensive panel construction, dramatically shorter service life, and lower electricity yield per area in a given location.
What you have proven, is that bike sheds with solar panels on top cost money, and likely will never recover their cost. Sure; I agree.
What you do not realize, that if you did the same calculation for the ground panels, considering how much more expensive they are as people and bikes will be stomping on them, and how fast they degrade (there are examples of bicycle path panels you can compare to –– two to three years is the maximum you can expect if used), the ground panels will recover even smaller fraction of their cost.
Simply put, they are even worse a proposal as a bike shed with panels on top, because they provide no comfort. It is just money thrown away.
If the argument is that putting the panels on the ground wastes less money than putting them on an expensive shed roof, it is an idiotic argument.
My argument is that at least the bike shed would provide comfort, and therefore value for the money "wasted", with the panels on its roof at least offsetting some of the cost. Putting the panels on the ground is just wasting money.
See?
nctnico:
The modules for this bike parking space don't see intense traffic. And it looks like these are well constructed including drains to divert rain water; this design clearly went through a few iterations. So for sure their lifespan is more than a few years. It would be interesting to figure out who is manufacturing the solar modules to get some actual data instead of wild guesses. Platio (for example) gives a 5 year mechanical and a 20 year performance warranty on their solar pavement products.
Nominal Animal:
--- Quote from: nctnico on March 05, 2024, 04:23:17 pm ---The modules for this bike parking space don't see intense traffic. And it looks like these are well constructed including drains to divert rain water; this design clearly went through a few iterations. So for sure their lifespan is more than a few years.
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The glass(y) surface will be scratched all to hell pretty quick, as seen from the bike path ones. The conversion efficiency will drop very quick. How quick, depends; but I would not expect glassy tiles walked and biked over, even just occasionally, to retain more than say 33% of their original efficiency after a couple of years, say four years max, based on places where glassy-surface stones/ceramics have been used as decorative elements on steps and plazas at various campuses. Consider what that does to your yield-over-lifespan versus cost calculations.
You also cannot assume the walked/biked on top of panels are as cheap as the rooftop ones. You need significant support for the panel to not crack, done in a way that does not cause temperature changes (day vs. night in Spain) to delaminate the panel from the concrete basis. You probably need structural steel there too, increasing the price of these solar panel slabs.
Anyone found the price figures for the slabs used in the various bike path solar roadways? I'd expect these to be comparable.
Then, there is all the converters and temporary storage needed to use the electricity for something useful, like in bike charging as they claim.
I bet those alone will cost more than a plain bike shed sans walls would. (Of course, they would be needed if the panels were on a roof of said shed.)
Just to point out how off your estimations are.
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