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The first solar road has turned out to be a disappointing failure

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Re: The first solar road has turned out to be a disappointing failure

#321

Post by mbrumlow »

kbutler wrote: post #246
ars wrote: post #217

Earlier quoted context omitted.

The ground pressure from a truck is around 150 PSI. A woman wearing high heels can match, and even exceed that. So the sidewalk would need to be just as strong as the road.

Common physics example, but it disregards how women actually walk and stand in heels. They walk on their forefoot, rather than balancing their weight on the heel. https://www.semanticscholar.org/paper/The-higher-the-heel-th... Shows less than 30 N/cm^2 (40 PSI) for women in heels - and higher heels result in lower heel pressure. Forefoot pressure is higher, despite the larger surface area.

Even so. It would be a flaw to not consider that at some point in time a women may put full force on the heel. Thus the example is valid.

Also I have seen high hees being abused by walking mostly on the heel.

Re: The first solar road has turned out to be a disappointing failure

#322

Post by Someone »

Retric wrote: post #176
Someone wrote: post #117

Earlier quoted context omitted.

I have serious doubts these experiments will lead to commercially successful implementations, but I don’t think it is useless to do them. Reason? Solar cells keep getting cheaper and cheaper. That makes the costs of scaffolding to hold the cells take a larger and larger share of installation costs. In the limit where cells are essentially free, putting cells everywhere there is some large horizontal area will make se…

Except we don't actually need that much solar power and ground based installation is really cheap. Further road surfaces need to be transparent for solar to work, handle high loads, channel water off the surface, and provide lots of friction in a wide rang of weather conditions. It’s an extremely difficult problem, but solving it without massive reduction in panel costs is kind of pointless.

Define “need”. If five billion people want to live as Americans live now, and Americans will all have flying cars (1), go on holiday in space stations, etc, and we want to put back the carbon of a few cubic miles of oil in the ground each year to fight climate change, what we “need” will be quite different from what we think it is now.

If solar cells become essentially free, we _could_ get there.

Also ”ground based installation is really cheap.” doesn’t matter. Putting cells in roads _may_ become even cheaper, even though the cells themselves would produce a lot less power per square meter.

”it’s an extremely difficult problem, but solving it without massive reduction in panel costs is kind of pointless.”

I didn’t claim it was easy or that it was efficient now. I just pointed out that reduction in panel costs can lead to a situation where using them in suboptimal settings can be economically viable, if installation costs are lower for that suboptimal setup.

And massive reduction in panel price has been the norm for decades. https://en.wikipedia.org/wiki/Swanson%27s_law:

”Swanson's law is the observation that the price of solar photovoltaic modules tends to drop 20 percent for every doubling of cumulative shipped volume. At present rates, costs go down 75% about every 10 years.”

(1) of course, if Americans start having flying cars, road surfaces may become a thing of the past.

Re: The first solar road has turned out to be a disappointing failure

#323

Post by fencepost »

Atheros wrote: post #271
fencepost wrote: post #257

Earlier quoted context omitted.

This was obviously never going to work Could be, and I suspect that a lot of the actual engineering folks involved would agree 100% on this point. They'd probably also tell you that 5 million for real - world experimental data on the exact ways in which it failed was very much worth it. Was there anything else worth responding to in the wordy pseudo-psychological insults?

May I please read the real-world experimental data that will save other companies millions of dollars?

That may not be made available depending on the company involved with the roadway. They may very well consider it proprietary information to be used in development of future products.

Re: The first solar road has turned out to be a disappointing failure

#324

Post by fencepost »

dredmorbius wrote: post #309
fencepost wrote: post #254

Earlier quoted context omitted.

numerous degredation mechansims (it's not just one), from fogging of the transparent surface to cracking, glazing from dust and sand, hail impacts, broken circuits, etc. Hasn't a lot of research been focused around ways to capture incident light and focus it down onto the actual cell surface? Iirc a lot of that has been things like surface coatings but is there really a requirement that's such a surface actually be i…

A concentrating system isn't going to reduce the overall degradation -- yes, there's less critical surface, but it's weathered about the same as a nonconcentrating surface, and affects proportionately more generating capacity. Or at least that's the theory. NREL conduct longevity / degradation studies for numerous specific PV panel designs and products. Degredation ranges between about 0.5% and 0.8% per year, with an…

I was actually thinking in terms of the pv and concentrating layers being physically separate, with a way to replace the concentrating layer similar to how roads are regularly resurfaced by removing an inch or two of surface and laying new asphalt.

Re: The first solar road has turned out to be a disappointing failure

#325

Post by nkoren »

Animats wrote: post #147
nkoren wrote: post #86

Yes, solar roads were always the answer to the question of "where is the absolute worst possible place to put solar panels". This was 100% predictable.

Could be worse.[1] Remember the schemes for recovering energy from traffic on sidewalks and roads? Pavegen pivoted to collecting info about people walking on their sidewalks, rather than energy. [1] https://pavegen.com/

Ouch, yeah, that's pretty bad. I've actually been at a fair number of events with these folks, as my own startup often gets put into the same bucket with them (also London-based and associated with "green" transport infrastructure). I've always avoided having a conversation with them, because it just seems so ...sad.

As a straight-up marketing device -- say, a way of creating some interactivity at your storefront in order to get people to linger there longer -- then I guess it's fine, or at least no worse than any number of other things. I actually find that less objectionable than painting it with a green "we're helping to save the world" veneer that is either very cynical or very deluded. It takes a trivial amount of cognitive effort to understand that energy recovered from footfall will never, ever, pay back the embodied energy to produce and install the device. (Even moreso if you include the metabolic efficiency of human power in the energy calculations). This shouldn't be hard to figure out: it was pretty well understood by the end of the neolithic. But I suppose people are capable of remarkable feats of mental gymnastics.

Re: The first solar road has turned out to be a disappointing failure

#326

Post by gbraad »

It is the dumbest idea to use a solar road when there are roofs; like bus shelters. train stations or even sound walls that can be converted. Cars would literally rip these roads apart due to dirt and grind.

Even EENblog made several videos about this in the last few weeks. Just have a look:

* https://www.eevblog.com/2019/08/07/eevblog-1233-the-demise-o...

* https://www.eevblog.com/2019/08/07/eevblog-1234-more-epic-so...

* https://www.eevblog.com/2019/08/18/eevblog-1236-german-solar...

Re: The first solar road has turned out to be a disappointing failure

#327

Post by zdragnar »

atq2119 wrote: post #284
zdragnar wrote: post #268

Earlier quoted context omitted.

Put them above the road and tall trucks can't go through anymore. Plus, the support structures needed suddenly become obstacles for cars to hit when making emergency maneuvers or drivers lose control, and now you've got tons of glass shards, electrified wires and steel supports falling down onto the freeway. Under the road is literally the only option, and it's a terrible option at that. Rooftops - or better yet, for…

There's a standard maximum height for vehicles that is taken into account for freeway bridges, so your first argument is nonsense. The rest still stands, of course. If you absolutely do want to put solar panels in the same place as cars, starting with parking lots is clearly a better idea. Fewer problems with high speed collisions, the electricity is generated closer to where it's needed, and people will be thankful…

"Nonsense" would only apply if practice were as good as theory; a very very brief Google search will net plenty of results for freeway overpasses and pedestrian bridges being hit. One example:

https://www.cbs58.com/news/truck-wedged-under-bridge-shuts-d...

Re: The first solar road has turned out to be a disappointing failure

#328

Post by ksec »

__sy__ wrote: post #261
craz8 wrote: post #259

Earlier quoted context omitted.

It’s never a zero sum game - we can try many things at once, some will work well, some will work poorly, some won’t work at all Trying things helps us move forward

And some aren't even worth trying in the first place. Like this idea. edit: I'm all for trying crazy moonshots. Just not down right idiotic ones that are pushed by pseudo-science and clickbait activism [1]. [1] https://www.vox.com/2014/5/14/5717036/should-we-cover-all-ou...

Excuse my ignorance, isn't this a technical challenge, rather than the idea in itself was stupid?

Isn't that saying shooting sky full of satellite for communication is stupid until SpaceX made loading anything to space 10x less expensive?

I would say the idea isn't worth trying because it clearly wasn't ready, ( I mean if napkin maths already show it is off by a factor of 10 than it really is stupid trying it ) but I don't think the idea in itself is stupid at all.

Re: The first solar road has turned out to be a disappointing failure

#329

Post by freediver »

egdod wrote: post #238
freediver wrote: post #230

Lets not forget that the first electric car was also a disappointing failure.

The first X was a failure for many good ideas X. But that does not mean that every (or even most) failures are just bugs being worked out of good ideas . Sometimes a failure is just a bad idea.

That was entirely my point.

Re: The first solar road has turned out to be a disappointing failure

#330

Post by BubRoss »

ksec wrote: post #328
__sy__ wrote: post #261

Earlier quoted context omitted.

And some aren't even worth trying in the first place. Like this idea. edit: I'm all for trying crazy moonshots. Just not down right idiotic ones that are pushed by pseudo-science and clickbait activism [1]. [1] https://www.vox.com/2014/5/14/5717036/should-we-cover-all-ou...

Excuse my ignorance, isn't this a technical challenge, rather than the idea in itself was stupid? Isn't that saying shooting sky full of satellite for communication is stupid until SpaceX made loading anything to space 10x less expensive? I would say the idea isn't worth trying because it clearly wasn't ready, ( I mean if napkin maths already show it is off by a factor of 10 than it really is stupid trying it ) but I…

What is the point of a solar road?
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