The first solar road has turned out to be a disappointing failure • Hacker News Board

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

#141

Post by beatgammit » Sat, Aug 17, 2019, 9:43 PM UTC

ergothus wrote: post #109

tootie wrote: post #42

Earlier quoted context omitted.

I find it hard to believe they were really unaware. They either overestimated the durability of their devices or were running a quasi scam.

I know nothing of the details here, so this is total speculation, but I can imagine value in going with a solution you know wont "succeed", if the data you get from the failure is valuable. Like, no need to spend money trying to fix the tractor problem if the leaf problem is too severe. If in practice the leaf problem only deteriorates things by 30%, that's different than 80%, etc. Spending the money to solve problem…

That's a pretty expensive experiment, and they could have tested each independently (install a few meters of panels near a tree and near a farm). Instead, they installed 1km of road and the minister of energy hoped to drastically increase the amount of these roads within a fairly short time frame (5 years), which tells me they didn't consider it an experiment (just a conservative rollout).

This feels like fraud to me, and some lack of reasoning on the part of the government officials who accepted this project.

Yes, $5M isn't huge by government standards, but it's pretty big compared to simpler testing options available to a company who plans to fall back to powering CCTVs (hopefully not with parking lot panels...).

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

#142

Post by Gibbon1 » Sat, Aug 17, 2019, 9:48 PM UTC

pbhjpbhj wrote: post #92

nullwasamistake wrote: post #79

Earlier quoted context omitted.

Solar roads and sidewalks are a PR stunt. Abrasion is no joke, nothing optically transparent survives on the ground. You can see this easily in the cellar "pavement lights" common in NYC and other old cities. Light still passes through after a century, but maybe 20% and very diffuse. Bad for solar panels. Roads don't absorb enough energy to generate power, they're not flexible enough. They're designed to not absorb e…

I think you misunderstood the parent, they said "solar covered sidewalks" that shade pedestrians, so roofs. Solar roofs on car parks seem good to me; better than using pasture land converted to solar farms which I'm seeing more and more in UK.

Yeah solar roofs on car parks is pretty good because the shade aspect is just a bonus.

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

#143

Post by beatgammit » Sat, Aug 17, 2019, 9:49 PM UTC

onion2k wrote: post #135

TillE wrote: post #119

Earlier quoted context omitted.

If we're talking about highways, you can usually find large stretches of empty space immediately alongside them, at least the same width as the road itself.

Sure, and above the road, and on the tops of buildings, and all over the place. Solar roads are a bizarre idea. The only point I was making in my post is that if all roads generated electricity they wouldn't need to be very efficient, so using that argument against solar roads is flawed logic.

How so? How expensive is an inefficient solar road vs a regular road with a more efficient solar plant next to it? I imagine that doing them separately would at least make each last longer, and would probably be cheaper on average.

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

#144

Post by tempsolution » Sat, Aug 17, 2019, 9:50 PM UTC

Well, that's hilarious. A solar-panel road. As if obtaining power efficiently from solar energy wasn't difficult enough. No you have to also build it into a road, which is also completely useless, even if it worked. We don't have a space problem. It's not like you couldn't place these things somewhere else...

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

#145

Post by Endy » Sat, Aug 17, 2019, 9:51 PM UTC

dumbfoundded wrote: post #124

Endy wrote: post #113

Earlier quoted context omitted.

If direct sunlight triggers a harmful reaction in your water, you need to reconsider what's in your water.

Not really. Bromide and chlorine are okay for humans to consume. Sunlight turns these into to bromate which is a carcinogen. https://www.sciencealert.com/here-s-what-s-really-going-on-w...

Okay, but do bromide and chlorine naturally occur in the water in that area? Or was it because of human meddling?

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

#146

Post by godelski » Sat, Aug 17, 2019, 9:51 PM UTC

blunte wrote: post #102

godelski wrote: post #64

Earlier quoted context omitted.

> Maybe expectations need to be adjusted, but experiments like this are worth doing! We don't know exactly what they will lead to, but they often add to progress. Except we all knew this would happen. It was all in the predictions. This was a scam. People did the math on these things. We knew it wouldn't hold up to tractors and heavy vehicles. We knew there wasn't a good solution to keep things clean. The problem is…

I suspect a lot of firsts (or early projects) were promoted in scammy, or at least very unrealistic, ways. I don't agree with overpromotion, but frankly a lot of what SV does is based on that as well. If your pitch deck doesn't promise to change the world, you won't get as much attention. This project was probably a poor use of funds (compared to other options), but the effort may have advanced our knowledge just a b…

That's not what I'm trying to say. You do have to be risky. But you don't have to lie. That's the difference between a scam and someone taking a risk (or being naive).

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

#147

Post by Animats » Sat, Aug 17, 2019, 9:51 PM UTC

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/

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

#148

Post by SllX » Sat, Aug 17, 2019, 9:55 PM UTC

jwr wrote: post #100

For some reason, solar roads are a very aggressive meme (in the classical sense of the word). They capture the imagination and blind people to engineering reality. Solar roads do not make any sense whatsoever, as you wrote pretty much any other place is better for panels.

They capture the imagination because there are plenty of places you don’t want to build solar panels. Namely places that you want to leave alone for ecological or recreational purposes. If you can take a piece of infrastructure that is pervasive throughout a built environment and give it additional purpose, then you can save on or reduce the land you specify for this purpose.

Does it work? Apparently not, or at least: not yet. We have not successfully accomplished this, but it remains to be seen if this is a case of not yet, or never will. Experimentation yields useful data, even when the experiment is a failure.

So where were the failures? The road was less durable than expected. They didn’t account for falling leaves. They didn’t produce as much electricity as they thought it would. Thunderstorms also damaged the road.

But! It did produce a decent amount of electricity, it did successfully transmit it, and it did function as a road. Colas has given up and chose not to pursue this route anymore, but it isn’t a death sentence for the idea in its entirety. It is a failure of execution, and there will be a lot of failures before there is ever a success. I’ll end this with the caveat that there might not ever be a success, but it is too early to decide that and further experimentation might yield other interesting road construction technologies.

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

#149

Post by panopticon » Sat, Aug 17, 2019, 9:58 PM UTC

soulofmischief wrote: post #80

onion2k wrote: post #66

Earlier quoted context omitted.

Those things are necessary to get the opimimum amount of electricity but the point of solar roads is to sacrifice some efficiency for the benefit of having huge amounts of surface area. The amount of paved highway in developed countries is enormous, so even massively inefficient solar roads could supply all the electricity necessary and more.

Could you talk more concretely? What is the back of the napkin calculation for total power if some percent of all highways were solar?

Not OP, but I was curious:

Let's assume a good solar panel yields 15 watts per square foot under direct sunlight. The DOT estimates about 1.5 million acres of interstate in the US.

Without getting too complicated, let's assume we produce at our ideal wattage for 3 hours a day. Given our ideal solar panel, this is 2.94 billion kWh per day.

Getting ideal conditions on a highway surface is unrealistic, so let's assume our fictional extremely rugged solar panel can only yield 0.25 watts per square foot. Now we're sitting at 49.01 million kWh per day.

To put this into perspective, the US produces roughly 11.45 billion kWh per day. So turning all of our interstates into inefficient solar panels covers less than a half a percent of our energy production.

Caveat: this is shitty napkin math and omits all other paved surfaces in the US of which I'm sure non-federal roads and parking lots make up a lot of, but I couldn't find good sources for those.

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

#150

Post by modriano » Sat, Aug 17, 2019, 10:02 PM UTC

pgeorgi wrote: post #99

WalterBright wrote: post #50

Earlier quoted context omitted.

> but who argued against solar roads because of leaves killing the efficiency? I had my concrete driveway pressure washed recently. It looked really good for about a week. Then leaves fell on it, and the leaves stained it brown again. All the engineers had to do was look at flat concrete.

concrete is a permeable material, solar panels not so much. If you coat your driveway with a resin cover, the stains will probably disappear every time it rains. But nevertheless, it wasn't a talking point before - of course, with enough observation you can think of all possible failure modes beforehand. Sometimes it's easier to just try things out.

But anyone who has read a book about designing a home solar system can tell you that all of the literature tells you that you have to pick the location of your panels carefully so they aren't occluded by trees over part of the year because the power losses due to occlusion are significant and can make a system non-viable and non-economic. From the book I read [0] (although mine is the 2015 edition), not planning for obstacles is the #1 reason solar power system designs fail.

I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project.

[0] https://www.amazon.com/Solar-Electricity-Handbook-installing...