To summarize his videos: solar roadways were never feasible even in theory with quick back-of-the-envelope calculations and all of the known solar roadways projects in the world have failed or are nearing failure.
“Cracks have appeared, and in 2018, part of the road had to be demolished due to damage from wear and tear.” as opposed to regular roads which never crack
“the road was only producing half of the expected energy” - great, so just 2 km of a solar road could power the streetlights of an entire city the size of Tourouvre, 3700 people.
We shouldn’t raise the white flag so quickly. I think we need a second iteration at least before we call it a failure.
> “Cracks have appeared, and in 2018, part of the road had to be demolished due to damage from wear and tear.” as opposed to regular roads which never crack
Regular roads don't fall apart in 18 months, they take 18 years (or longer) to do so.
Touche, a good point, but a first attempt is not usually reliable. I think we should learn more about what could be done different? Should instead all bike lanes be made of solar “panels” because the wights is all yet they would cover a large surface if they were to cover the whole city? How does a traveled road get covered in leaves?
Cracks don't cause a regular road to fail entirely, while if a solar panel cracks in half, it will most likely stop working.
Also I don't see how solar roads make any sense when there is so much unused roof space and parking lots. Putting panels over a parking lot is much easier since you don't have to build them to withstand many-tonne automobiles, they will always be in full sunlight instead of being covered by dirt and vehicles, and they can be angled towards the sun. Even in theory, I think solar roads are a failure.
I suspect the idea was partly that we already have to build infrastructure for roads; why not make the roads also a source of power?
In practice it will take many iterations to reach a point where it makes sense. Or it simply may never make sense.
The recent articles about some California farmlands being converted to solar fields does make sense. They were running out of water, but they had a lot of land to use for something.
Even if solar roads can work, there's still the problem of relatively inefficient tranfer of power over long distances. It makes little sense to spend a lot of money to make a solar road that's far away from energy consumers since a lot of the energy produced by the road will be lost in transit.
So after my erroneous comment, i have learned that roofs, parking lots and bike lanes are better candidates. I just dint want to give up on converting asphalt to energy generators.
Think the person you responded to meant for the solar panels to be above the parking lot, not the parking lot surface. IIRC, Google has quite a far solar panels in their parking lots, where they not only generate electricity but also provide shade for the cars parked there. I've also seen a couple of rather massive solar panels in central Atlanta near CNN. I was told they were installed by Ted Turner because he has a penthouse nearby. No idea how much power they generate but it does provide some nice shade.
There was a different comment recommending parking lots, and i summed up all my thoughts in the comment above. To me it sounds like France could use some shade as well as some clean energy. Calling it quits is just not an option given the crazy heat waves of recent in Europe, and we should hold onto to anything that improves what we have right now even if by 1%.
It's a fundamentally stupid idea. Passing solar light requires transparency. Transparent materials (glass, plastics) wear quickly and make terrible road surfaces. Texturing the surface to make it a better road reduces transparency and increases wear even more.
How about solar (covered) parking lots, solar roofs, etc. It makes far, far, far, far more sense.
Road surfaces need the ability to flex while withstanding huge loads. Materials such as asphalt have this ability. Glass, in layers thick enough to support the loads necessary do not.
Bitumen can also be patched and repaired relatively quickly and easily, and can use relatively simple machinery to repair/replace large sections at once. Solar panels require a lot more surface preparation, precision joining and when they break (because they will - accidents happen), leave dangerous road surfaces that cannot be easily patched/repaired.
Solar Roadways won't work with our current state of technology where we need fixed rigid panels. Something that is either a replacement for bitumen, or can be mixed into it and is able to self-assemble a current pathway might be a viable option. But we're a long ways off doing anything like that.
It was a failure but I’m glad they tried it. Hopefully something like this comes to fruition and we learn more and more with every iteration. Solar roads are a great idea. Maybe it means it needs daily sweeping with electric vacuum trucks or something but if it’s producing enough electricity then it’s worth it.
> It was a failure but I’m glad they tried it. ... Solar roads are a great idea.
It was a bad idea. Even in theory. The only positive thing about it is that it captured the imagination of lots of people who know nothing about solar or roads.
The frustrating thing was that pretty every problem that arose during these trials were already known. Those who spoke up were ridiculed for being naysayers. There's a balance between those who reflexively oppose everything and those who have an informed opinion based on experience and knowledge. There was quite a bit of overlap between those who strongly supported solar roadways and the "I f*ing love science!" crowd that have turned science into something indistinguishable from magic.
The original installation in Idaho ran into predictable problems almost immediately. The much larger installations had very little justification for going forward other than it was very popular with a rather vocal group of voters. Doubt any of the politicians, celebrities, or their fans who pushed this and dumped all over those with credible objections will apologize for their part in the boondoggle.
I'm of two minds about what you're saying. On the one hand, it looked like a bold failure from the start. On the other hand, it put the idea of solar generation in "unorthodox" places into the minds of normal people and city planners alike. Solar roads aren't the way to go - but how many people, having heard about the project, encouraged their city to put up solar panels on all the light & phone poles? How many people have taken the enthusiasm from this project and looked to see where they could safely generate power from secondary sources in their own lives?
So it's a great idea, and it's also a massive and fairly obvious failure at the same time. The message to take away from this isn't just "solar roads were a bad idea". It's that "solar roads are a bad idea, but we should keep looking at other ways to safely generate the energy we need around roads and urban passages."
The only positive thing it did for me was kill my faith in humanity. The fact that this type of thing had enough credibility to get public money indicates an absurd level of failure in critical thinking.
I just don’t see how it’s worth it at all compared to putting solar panels on top of buildings.
Solar panels on buildings don’t need to be as rugged, don’t need to be cleaned daily, etc, and they also can be oriented towards the sun to maximize output.
Solar roads are a solution looking for a problem. I can imagine they’d be useful to squeeze out an extra few % of output in a world where everything else is covered in stationary panels, but we’re far from that so I don’t see why we should invest lots into them were the same investment would pay much more if it was about stationary panels.
And the craziest thing is that the sunniest parts of the planet are completely uninhabited, so land is plentiful and cheap. As opposed to urban areas, which are the most expensive real estate that exists.
What do you mean by the "sunniest parts of the planet"? You mean the deserts? Not all countries have that luxury and maintenance might prove challenging, depending on the desert.
I think putting a roof on streets (on a relatively light aluminium/carbon fiber scaffold) for the panels is less outlandish than trying to fix "solar roads" by adding maintenance vehicles (or solar roads themselves, really).
It keeps away rain (which improves driving), doesn't expose the panels to the weight of tractors, has similar safety properties (the panels need to react quickly on any accident related impact and isolate affected circuits to avoid electrocuting passengers), and if slanted, is somewhat self-cleaning in wind or rain.
I agree though that it's nice that somebody did a field test. That idea sprang up again and again and it helps to have some real world data: people anticipated the cracking issue, but who argued against solar roads because of leaves killing the efficiency?
> 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.
> because the power losses due to occlusion are significant and can make a system non-viable and non-economic
That depends on how large the individual cells are and how they're wired up. There are panels that have a pass-through if they're occluded too much to avoid them limiting the output of other cells. It's possible that these panels had compensation mechanisms built-in.
> I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project.
This isn't a few amateurs getting a construction grant and slapping the cheapest off-the-shelf panels they could find onto the pavement.
The panels were built by a French company called Wattway, a subsidiary of Colas, a large French street construction corporation. The parent company also did the construction work of actually putting these things on the street.
Apparently the "Institut National de l'Energie Solaire" was involved in this project as well, which is a public research facility (co-run by a university and the CEA, which has a budget of more than 5 billion Euros, and has a staff of 19k employees and 1200 grad + post-grad students).
That "solar road" might have been part of a research grant for all kinds of PV developments and they had to deliver it as a demonstration. That would also explain to me why they give up so easily. From the article: "Wattway [...] told Le Monde that it would not be going to market."
I'm all for trying things out, but this idea was always pretty crazy. It sounded nice at a very superficial level. Good solutions usually solve multiple problems, and this "solution" combined some problems... Seems like a smaller trial would have been just as effective
I'm not. Research funding is very much a zero-sum game. Because they spent that much money trying something that stupid, it's safe to say that some actual good ideas either didn't get funded or had to make do with less.
we learn more and more with every iteration
There was nothing to learn here. It was easy to predict the outcome based on well-understood models, and countless people did.
Because minimizing ground covered with man-made stuff is a goal worth chasing. Leaves more of that thing called "nature" intact and doing its job, which - among other things - is to keep us alive and breathing.
Hence the idea of dual-using those insanely large areas covered with concrete that we use as roads is a great one in principle. We do the same with rooftops already, and it works great. But roads appear to be much more challenging than rooftops.
Some quick searching reveals various estimates of 1.6% to 0.7% of the US being paved over. That's including parking lots and cities, places that probably aren't good candidates for solar roads anyway.
Seems like you might get greater benefit by sacrificing yet a little more of that thing called "nature" (never heard of it before, thanks for sharing, TIL) and realize actual benefit than using the same amount of resources to solarize roads for a fraction of the benefit.
I'm sure if we invested vast amounts of money into specially curved road surfaces we could make square wheels work[1]. That would still be dumb when compared to round wheels.
The problem with solar roads is it's plainly worse than the obvious alternative: putting solar panels next to roads, or above carparks.
And innovations that made them more plausible as a road surface are also going to make for a better regular road surface, or a better mounted solar panel.
Maybe next they could design an airplane out of bricks. Or try using water as an automobile fuel. Or that silly experiment where they tried to make a jet fuel that wouldn't burn:
Why wasn't that strip of land right by the road converted into a solar strip instead? It looks like that shoulder has almost as much physical area to it and would take a lot less wear and tear.
This article from 4 days ago says a solar road in the Netherlands is doing well, so it seems like the French road is just a bad design? I don’t know if they are in fact different hardware:
The one in the Netherlands seems to be a 70m solar cycle lane. Cars will destroy a surface a lot faster than bikes. Maybe (dedicated) bike lanes would be a good place to start with this.
That sounds like a good idea. It would also give cities more incentive to keep the like lanes well maintained (even in bike-friendly cities, bike lanes are usually less well maintained than motorways). One problem is that bike lanes are often located close to shade-providing buildings or vegetation.
I think it'd be much better putting panels over roads. It uses pretty much the same footprint and it'll reduce the effect of roads being huge heat sinks they are.
This seems like a massive undertaking given that those panels would sit atop fast moving traffic and stand up to the elements (like tons of snow). But I'm sure at some point it will be perfectly feasible.
It's not obvious to me that cars will destroy a surface faster than bikes. Yes, cars weigh a lot more, but that weight is distributed over a larger area. The force on a given square millimeter of the surface that the vehicle is on is actually 2-4 times as high for a bike than from a car. This is why bike tires typically are inflated to 2-4 times the pressure of car tires.
It's not the point load, it's the total load. Which bends the road. Bending brittle things like solar cells cracks them. Movement of the car also causes compression waves to move through the roadbed.
Roads need regular resurfacing because bending the roads constantly causes them to crack and crumble.
Maybe the cyclists avoid the solar section. Remember, cycles are a lot less inherently stable than cars and provide much less protection in case of a crash, and glass is slippery. Even metal manhole covers get a little scary when wet.
Help me understand the logic behind taking a PV and stepping on it in the worst possible way, leaving dirt , rubber etc, when every PV that is exposed only to the open air needs regular cleaning / maintainance. And its being frequently under the shade of cars
Self-cleaning glass is a fairly mature technology and will work effectively on a rooftop solar installation. That won't work on a solar roadway, which a) needs a textured surface to provide adequate grip for vehicles and b) can't retain any sort of coating due to friction and c) is constantly being covered in axle grease, tire rubber, brake dust and the innards of various wild animals.
The article starts with the wrong assumption that you have to hire people to clean the solar panels. Robots have taken over that job a long time ago, at least for utility scale solar.
There is no logic behind it, only blind idealism. Unfortunately the couple who invented solar roads poured a lot of time and money into this idea and couldn't back down. Many people followed their enthusiasm.
I think one of the most difficult things you can do as a person is to be honest with yourself and admit when something has failed or won't work and to abandon it, but stories like this are reminders to really self reflect.
Solar roads seem like a really cool technology. Like, if they worked great and were affordable and everything, then awesome!
But, practically speaking, they seem to violate the [single responsibility principle](https://en.wikipedia.org/wiki/Single_responsibility_principl...). By coupling a solar panel to a road, we're forcing the physical entity to comply with competing objectives.
Seems like the future's prone to be different, anyway. For example, how long are we going to really need roads that're driven over at-random like today? Seems like self-driving cars could be designed-and-programmed to drive over just specific parts of the road meant to handle their weight, while the gaps between those load-bearing parts can have solar panels.
> Seems like self-driving cars could be designed-and-programmed to drive over just specific parts of the road meant to handle their weight, while the gaps between those load-bearing parts can have solar panels.
if you can drive that precisely, why even put anything in the gaps?
Same reason we have safety rails around roads. Plus, if we want solar roads, solar power would be a perk.
I mean, once the road is dominated by self-driving cars, presumably we can implement new driving requirements beyond what human drivers could implement.
For roads, we might want cars to drive over load-bearing parts, if that's optimal. Or if it's more efficient to have the wear-and-tear distributed, then cars can drive in staggered formations, much like a wear-leveling strategy in solid-state drives (SSD's).
But, there's no reason to design a transportation system around the premise that self-driving cars can't control their patterns just because human-driven cars couldn't.
Which isn't to say that we should assume that self-driving cars will be perfect or infallible, just that we can assume best-effort strategies. For example, we shouldn't assume that self-driving cars would never drive over a gap with a solar panel, but we can design a system in which self-driving cars try to avoid driving over the solar panels.
You know you kind of described how trains work? :)
I just did a quick calculation for Poland - we have 11k km electrified train tracks, with ~1.5m of space between the rails. If I calculated correctly, putting solar panels there would give us ~8-15tWh energy per year, which is 5-10% of the required electricity production for the nation.
I've never been a fan of the idea of solar roads, but solar railways might actually make sense...
I don't know how they do it in Poland, but in some countries when you flush a toilet on a passenger train going above a certain speed, the nasty stuff just evacuates to the space between the tracks.
Seems like any sort of solar panel on the ground is going to be prone to get nasty stuff on it.
I guess they might just have them at an angle, then trust the rain provide some light cleaning, while a street/rail-cleaner could go by for more thorough cleanings periodically?
I mean, I dunno what exactly their strategy is, but I'm assuming that they're not counting on a road to not get dirty. Cars leave rubber from their tires, drip oil, drop trash, etc..
Mechanical equipment, and freight, tends to fall onto tracks. Axels need lubrication, there are hydraulic fluids, potentially septic drops, and bulk containers (coal, sand, gravel, metal, scrap, grain) also leak from bins. None of these do much to improve efficiency or lifetime of solar panels.
Rail has adjacent easements. These have traditionally been used for complementary technologies, e.g., telegraph and other comms routes (which share a need for continuous rights of way, and provide a utility to the railroads themselves for communications and control services).
There are reasons you might want to avoid certain co-sitings (e.g., unarmoured petroleum or natural gas lines adjacent to rail trackage). But solar could well be a reasonable adjunct.
Fortunately we didn't give up on flight after the early airplanes.
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.
> Maybe expectations need to be adjusted, but experiments like this are worth doing!
No they are not. Solar roads do not make sense, not for a looooong time anyway.
So far, all of the currently failed solar road projects have failed in utterly predictable ways[1][2][3], and I'm certain nothing novel has been learned.
There are so many better places to put solar panels than beneath roads. If anything they should put water pipes to utilize the heat. But solar panels, that's like trying to optimize a function for another 0.03% speed while there's still order of magnitudes of trivial improvements laying on the table elsewhere.
Sure, I tend to agree with you. But as I posted to another reply, it's conceivable that this silly experiment will lead to improvement in material science or some other construction/manufacturing practice related to solar panels.
And hey, we can't be too hard on them for perhaps jumping on a bandwagon. Solar roads seems more plausible than food delivery service on "the blockchain".
The only thing that they could have contributed with is making flexible solar panels. But they didn't. Instead they just put down regular panels.
Assume they actually made flexible panels. They'd still have the issue of the abysmal efficiency due to the inevitable grinding of the surface and dirt filling up the cracks. You'd need frequent washing of the roads to keep them clean. Was that included in the energy projections?
Missed by most people is that roads flex under the weight. (Stand next to the train tracks when a train goes by, you'll be startled at how much the ground moves.) Flexing of the roads it the primary cause of road maintenance - cracking and crumbling.
Silicon chips in the roadbed, wires, pipes, etc, are all very vulnerable to cracking under bending loads. Putting water pipes in the roads mean you'll get innumerable leaks in short order.
I know there have been some applications of piezoelectric floors put in places people walk (to generate small amounts of electricity). I wonder if this could have some practical value in roads. The energy would be small, but perhaps it would be enough to keep some distant electronic systems fed.
The problem with piezoelectric flooring is that the power generated is "stolen" from the person crossing it. Take too much power, e.g. by having a perceptible deformation of the surface, and the person will have the feeling of walking on soft sand or snow and may avoid walking on it. Take too little and the exercise becomes pointless: even with a very generous set of assumptions the PaveGen system produced 1/5000th of a person's power need.
That said, we have the technology to make flexible pipes. It'd still be a pretty dumb idea, but at least a few order of magnitude less dumb than these solar roads.
I agree that we as a society generally need to afford ourselves to be brave and fail sometimes. But... this seems like such a bad idea even in theory.
Road surfaces have pretty specific and harsh needs, which currently can be mostly solved with really cheap solutions (concrete/asphalt). Photovoltaic cells on the other hand are comparably very expensive and fragile.
Surely, land can't be that expensive in most places that it makes sense to use the road surface, compared to say roofs.
I can't speak much about other countries, but the US blows unfathomable amounts of money on incredibly narrow-sighted projects (particularly military). But yet, some of what is learned from those projects benefits science and technology.
I think what we might gain from this solar road experiment will be related to material science in the area of solar panels. Just look at mobile phones; surely the transition from old plastic in front of LCDs to "gorilla" glass has benefited other use cases. I'm just guessing here, but I bet there is something to learn which can be applied elsewhere.
I think flying cars are absolutely moronic and completely impractical. But who knows... maybe the brainpower spent trying to make them work will result in better traffic management or people transportation elsewhere.
> Fortunately we didn't give up on flight after the early airplanes.
Airplanes are not amenable to hackers designing them. Getting one to fly required a directed engineering effort, with a series of prototypes each targeted at solving a specific problem. I think it was the first such project that did so.
The Wrights are often dismissed as "bicycle mechanics", but if you take a closer look they were very competent engineers.
(The difference between an engineer and a mechanic is math. The Wrights did not try random things, they used math to arrive at solutions.)
I would disagree. History is full of airplanes that were built or modified (sometimes improved) by hackers.
There's an immensely successful experimental aircraft industry, and I'm not just talking about people who are (successfully) building human-scale vtol drones.
> History is full of airplanes that were built or modified (sometimes improved) by hackers.
The FAA won't let you fly it until an engineer goes over your design. For very good reason.
An unbalanced airplane isn't going to fly, and one that isn't strong enough will fold up on you. There's a thin line between strong enough to hold together and light enough to get off the ground - and you cannot find that without math.
There were many hacker airplanes before the Wrights. They were all too heavy, too underpowered, too unstable, and too weak to fly. The Wrights, with math, solved those problems.
My issue with it is the scaling. They had a test installation in sidewalk which proved to be woefully inadequate. Yet the pushed on, largely unchanged. They took two things which have significantly different requirements and tried mashing them into one.
Solar panels need to be oriented towards the sun to maximize energy, and need to get as much sun going through the glass to the panel as possible. You basically end up multiplying many variables together to get the end efficiency, and we're actively degrading 3 by a significant degree by adjusting the glass/plastic to withstand the weight of cars and semis, scratching the surface over time with the dust and sand, and mounting them flat.
Roads need to be cheap to install, need to be long lasting, and need to assist vehicles in stopping quickly. I'd love to know the difference in stopping distance and coefficient of friction between this and traditional roads.
> 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 that this wasn't sound from even basic engineering.
I wouldn't call it a scam if they were honest about this. If they said "yes we need to do more testing" and "this test will help us figure those things it". But they didn't even do the background research. They called everyone that did may sayers. There's a reason only the IFLS type crowd liked them and not actual engineers.
I'm all in favor of doing hard tasks. Using government money to take risks in science and engineering. That's something we need to strive for. But things like this make it harder to get support for that because this was a joke from the beginning. Experts knew it was a scam from the get go.
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 bit.
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).
The solar industry knew that it wouldn't work. Anyone with a high school understanding of physics could figure out that it wouldn't work. The early trials failed spectacularly and nobody learned anything new. Subsequent trials also failed spectacularly and nobody learned anything new. People are still funding trials with exactly the same flaws as previous failed trials, presumably due to some sort of magical thinking.
Science should at the very least be informed guesswork - if you don't start with a reasonable hypothesis and don't update your hypothesis in light of the evidence, it's just alchemy.
So the idea isn't too crazy, it seems. Maybe it is unsuitable for heavy vehicles, or in areas where particulate is more likely to collect and affect the light gathering; but to some degree it can be successful.
The silliest thing about this road is that France already has very low carbon electricity, only 7.2% of electricity produced in 2018 was from fossil fuels...
Most solar panels are very inefficient at converting the sun to electricity so they need all the help they can get. Two things solar panels require is to be clean and to be perpendicular to the sun. A solar road achieves neither of those things.
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.
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.
Why the 60x output reduction in normal vs. road solar?
With say a probably still generous 6x derating, it would mean 2.94/6/11.45 = 4% of electricity production.
If you manage to avoid road solar tax (say by putting it above the road), it gets to about 25% of electricity production. Assuming a less pessimistic capacity factor of say 16% [1] gives 32% of electric production. Build a 3x wide solar cover over the interstates and .. use your imagination.
That puts your estimate out by a factor of maybe 25 or more (depending on road width) if all roads are converted to solar. And that's before the other paved areas like parking lots.
I'm not advocating solar roads. They're a strange idea with many, many flaws, but the inefficiency aspect isn't one of them. If you want to generate lots of electricity with solar you can have one very efficient array, or lots of inefficient arrays. Solar roads are the inefficient one.
Also, I would be preocupied by the ways to carry this hypothetically produced energy.
Right now we have either small "local" productions with "local " consumption (that works well as there is little distance to be covered) or "large" production concentrated on one site and with tension raised to thousands of volts to allow delivvery to the final user.
A "solar" road would probably make sense only in urban areas (where there would be other issues, like - say - shadow from buildings, less time of road free of vehicles, etc.) to avoid the issue of transporting the energy for long distances to the final users (or have a huge loss in the process).
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.
Go, fire up your favourite sattelite image service and check out how much of a typical urban area is really sunlit streets or parking lots. Bonus points for images where the cars that are present are on it. Ah and in an urban environment count shadows in. And quarter whatever figure you got because of dirt, abrasion and failure.
And now compare them to the areas of rooftops you find. Go ahead and do it.
My 5 min of reading the article and thinking about it idea is thus:
A slanted roof angled to shade and water/snow protect the road, shedding runoff in to a gravel area beside the road with drainage considerations accounted for. The far side might have some sort of attached tarp over part of it, and there'd be a gap between top of said tarp and the bottom of the panel roof. That would promote heat-stack ventilation along the underside of the panels and thus also SOME cooling.
Median strips and easements are a possible siting location.
Shade awnings over car parks another.
The challenge with solar power really isn't sufficient area for siting. It's low-cost installation and low-disturbance environments which ensure long panel life and low maintenance costs.
Solar panels have a useful lifetime of about 20 years, due to 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. NREL (the National Renewable Energy Laboratory) in Colorado have published research on this.
Engineering low-cost, long-lived, readily installable and replaceable panels would be a generally advisable research direction. Looking for extreme siting locations (e.g., high-traffic highways, or even sidewalks), or even, counterintuitively, greater efficiency, is relatively unimportant as compared to total costs and lifetime.
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 in contact with the cell? Could there be something that was effectively a replaceable capture top surface possibly with an air gap above the actual photovoltaic cells?
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 effective lifetime of 20-30 years.
Rough number, and actual results depend on specific siting characteristics and events. A tornado passing overhead, sandstorm, or very severe hail, may significantly negatively affect experienced lifetime.
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.
The lifetime is better than 20 years. They produce 80% off their original power after 20 years but it's not like they stop working. Nobody would bother replacing them at that point.
Correct, in that the degredation is to about 80% of original rated life. Actually, checking on NREL's site, it looks as if there's been some improvement, with 25 years a more accurate estimate. https://www.nrel.gov/pv/lifetime.html
However the point remains that 20-25 years is the standard rated lifetime for planning and estimating purposes.
The video attracted so much undeserved attention that many engineers felt that they had to produce a corresponding debunk video explaining why it is such a useless idea and why asphalt is currently our best option on building roads.
They also didn't think about the pressure and weight from tractors
I mean, the hell? I wouldn't put solar panels in a playground, because I would assume 50 pound children running around would destroy them. Obviously, motor vehicles will. And very quickly.
"The engineers also didn't take into account the effects of leaves, which caused damage and limited the amount of electricity the panels could produce. They also didn't think about the pressure and weight from tractors, two locals told Le Monde."
This + quasi-scam. There's a lot of money to be made in the "going green" space and if lying about your product gets you the contract, only the government (citizens) lose and you laugh all the way to the bank. I wish more government contracts had forced warranty / refund clauses (whatever those are called).
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 problems on your first run is likely to not actually solve all of them.
Then again, this could be a bold exercise in fraud and/or incompetence.
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...).
As a proof of concept trial it wasn't very expensive. Unrelated, but just for comparison it cost about a much as Uber lost every 2.5 hours in 2019Q2.
They built a Minimum Viable Product for a trial and found out that it wasn't actually viable and didn't provide the hoped for value. They probably also learned a lot with real world experience (that they wouldn't have been sure to have in a staged setup) and may come back with something different in the future.
Personally I'd be curious about the math on how much these panels pick up, whether some kind of contactless power transmission would be viable at highway speeds, and whether in 15-20 years we'll see interstates paved with these providing trickle power to fully automated electric trucks running as "road trains" across the country.
Still, power sourced from solar or wind in general and adequate to offset some of the "maintain speed" level of power draw? That seems more likely. If you have some way to provide maintenance levels of power during movement that may mean a significant savings in battery weight and overall cost, and if you don't think that matters take a look at the skirts under a lot of trucks designed to reduce drag.
Have there been any trials on creating a solar roof over highways? It seems like a much better option as the panels don't need to be reinforced, and they can be angled towards the sun to aid cleaning. We already know how to build stable metal framed structures (and panels aren't that heavy). In somewhere like Spain it would reduce the requirement for AC while driving, making it even more green. During rain it would increase visibility and reduce water on the road, making the road safer.
If you're building new structures I'm positive that the economics work out better for simply doing separate solar farms. Building them above a road has no major advantages and potentially both increases construction costs and increases the chances of unfortunate interaction (eg an accident taking out panels).
The sweet spot for solar roads would be in places where the generation benefit outweighed the extra cost when a road was being redone anyway - and even then only if the materials were up to the task.
Still, it might be a simple division of labor thing: one group specializes in believing, hard, and pulling in the money, another group says "well, they've got the money, let's try to build the least bad version of this travesty, if we don't take it someone else will"
I haven't seen anything from it yet that would convince me that it's not a scam. The fact that there are people defending this after all this time baffles me.
I have come across quite a few “green” initiatives over the past several years which are extremely questionable in their technicals - and all are taking public money, mostly from European Development Funds in the EU, and from similar bodies elsewhere.
They are usually highly visible, buzzword bingo initiatives. You see these projects in the press - a group grinning in hard hats, a colourful initiative behind them. You go back a few years later and it’s tape and barriers and broken glass and danger signs.
Whether folks start with good intentions but then move on, or don’t have adequate plans for maintenance (which then makes one wonder why funding was granted in first place), or simply see an opportunity to extract wealth from a public body, I don’t know.
An anecdote: a service station near my home in north wales proudly announced that they had received a grant to put on a turf roof, solar and wind power. EU funding. Three years on, and they’ve just announced that they’ve received a grant to do exactly the same thing. Plumbing the Europa site shows that the previous grant was paid, and the project reported as completed - but they never did a thing. I’ve seen the same cycle being pulled elsewhere.
There is such a push for governments to be visibly green that they are spending money on highly visible nonsense. The current elected power gets the boost for snipping the ribbon and providing the funding. Their successor gets a beating over the wasteful failed project.
There are good green initiatives happening, but it’s usually where nobody is looking.
> An anecdote: a service station near my home in north wales proudly announced that they had received a grant to put on a turf roof, solar and wind power. EU funding. Three years on, and they’ve just announced that they’ve received a grant to do exactly the same thing. Plumbing the Europa site shows that the previous grant was paid, and the project reported as completed - but they never did a thing. I’ve seen the same cycle being pulled elsewhere.
This should be reported to media, police or both - this is fraud.
After my previous experiences reporting fraud to the police, I think it’s best I leave them to figure this out for themselves. I don’t particularly want to be arrested, or charged with fraud.
I remember at the time this was announced, I was working at a startup in the solar PV industry. Our collective response on the workfloor was, "wow, that's an incredibly stupid idea for so many reasons". Surprised it took them so long to admit failure.
I can't imagine how hard it must have been, in France of all places, to try something that bold and risky and obvious to oppose beforehand.
We're the country of ruthless self deprecation coupled with perfectionist universalism.
I hope something was learnt here (other than learning not to do it again), and I'm absolutely confident the people who cluelessly pushed for it will go on their public careers unaffected while the innocents are punished.
We've done more insane stuff and survived to tell the tale.
> We're the country of ruthless self deprecation coupled with perfectionist universalism.
I wonder if there traits make you good at nuclear power. Perfectionism and ruthless self criticism seem like they'd engender the kind of thorough and methodological approach that keeps reactors from getting explody.
The Russian "can't duck it, fuck it" attitude seems to have the opposite effect judging from the Geiger counter readings.
>I hope something was learnt here (other than learning not to do it again)
I'm afraid not - the trials played out exactly as the naysayers predicted. Most of the panels cracked under load and failed due to water ingress; those that didn't became woefully inefficient due to soiling. They were dangerously slippery even in ideal conditions, they cost much more than a conventional rooftop installation and they never generated as much electricity as a rooftop installation even when they were brand new.
The whole exercise was a complete waste of time and money.
French arent afraid to be weird. Let me introduce you to Renault Twizy - a road legal mobility scooter, and Avantime - the only coupe minivan even made, a 2 door with no B-pillars, sold as good as that description sounds.
I think the best for societies is solar roofs. Much better surface availability. Solar roads, filled with thousands of cars cannot suck energy from sun so well as houses' roofs.
French officials said the road, made of photovoltaic panels, would generate electricity to power streetlights in Tourouvre, a local town.
I don't know how reliable they are, but solar-powered streetlights are already common in some areas --- and being mounted high above on the lights themselves, the panels are far less likely to be damaged.
I never managed to see the advantages of having a solar road compared to just having a normal road with solar panels next to it. Or above it. Or literally anywhere else. In fact I can't think of many areas that still get direct sunlight that would make for a worse place to put solar panels than on the road...
> Colas, the company that built the road, said in 2016 that the solar panels were covered with resin containing sheets of silicon to make them capable of withstanding all traffic.
I'm going to bet they said that after the check cleared.
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 sense.
Now, of course, we may not get close enough to that limit for this to make sense, cells may be too fragile for mounting in a road, there may be plenty of more profitable places to put solar cells, etc, etc, but that isn’t guaranteed, and we can’t tell without experimenting.
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.
”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.
I was more thinking We as in people alive right now. In 100 years things could be different, but based on current trends it’s not going to be useful in our lifetimes.
So many things are wrong with using solar road surfaces that it’s hard to make them look viable even if the panels cost nothing. Because that means electricity is worth very little, and you still need to integrate them into the road surface which costs money.
> Why not both? Neither works right now, it's probably prudent to try as many interesting things as possible.
1. Solar roadways is a terrible idea that will never be a good idea. It is strictly worse than building a roof over the road and putting solar panels on that.
2. Roughly half the renewable energy on earth comes from decaying isotopes and half comes from sunlight. If humans want more than that, they'll basically need to get it from sunlight not hitting the earth i.e. solar power satellites. That is a road that we'll eventually go down, but not for quite some time.
I don't understand why we can't pursue all of those options at the same time. Especially solar road vs laser energy from space.
Solar roads has the distinct advantage over covering all the roads in that it's not an eye sore and fits more seamlessly in the scenario we figure out the engineering.
> I don't understand why we can't pursue all of those options at the same time. Especially solar road vs laser energy from space.
There's this idea in economics called opportunity cost. The simple version is that if we fund bad ideas that can't possibly be good, we lose out on the good ideas we could have funded but didn't.
This is the reason you don't heat your house by burning paper money. You'd rather have rent and groceries and heat instead of really economically inefficient heat.
The advantage that people wanted to get is that in the end you also get a road.
Roads take up space, cost money to build and maintain. If you build it next to the road the road need twice the amount of space and still require the space, construction and material for the actually road. If you build it above the road you get all the issue of overhead roof on a road (trees that fall on it, wind, height limitation).
In addition to saving money by not actually building a normal road, the idea in most of solar roads projects is that it combines the work of putting internet and power cables into the ground.
That it currently do not work economically is the issue that the article showcase. Maybe it will never work and it always will be cheaper to simply build the road with current construction methods, put internet/power cables under it, buy large lands (farming land?) and construct regular solar parks.
Other concept of combining solar panels and building materials that is argued as more cost effective are roofs on houses. Same concept as solar road, ie that you get a roof and a solar panel in one without spending the work and material for both, but I have no idea if the economics is better than solar parks or if it is cheaper to just build normal roofs and go the route of getting land and building solar parks separately.
Water drainage is still going to be a big problem, as is damage/scratching caused by shoes, bicycle kickstands, trolleys, anything else with wheels that is pushed/pulled, you name it. Plus the simple fact that most sidewalks (at least here in the city) are often in the shadows of buildings.
It only makes sense to start thinking about sidewalks once you've covered all the roofs, which are way better in every sense.
Surprised this is getting down voted, this is a common example in physics 101 describing the concept of point pressure. Architects have to consider the point pressure of heels when designing certain walkways.
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.
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.
It's not that simple. Looking at the damaged roadway, I see lots of punctate damage. That puzzled me until I read your comment. I'm pretty sure that it's gravel under truck tires. So the same force-concentration dynamic as high heels.
Not only that, a common problem round here (UK) is that trucks park partially on the pavement. They routinely crack two-inch/50mm thick concrete paving slabs. I'd like to see a solar panel that can withstand that.
Sidewalks are still flat on the ground, which is not great in much of the world (like Normandy) where sunlight comes in at an angle. You would still get some generation, but would it be worth it compared to cells mounted elsewhere at a better angle, with less need for hardening, and less accumulation of dirt? Doing this on the sidewalks would add a lot of costs and complications.
So the problem is that a normal road costs on the order of $3 million per mile, and a solar road costs... 10 times as much. And it doesn't last as long.
It is plausible, but how much money is actually saved if you need to build panels that can stand wear and tear of vehicles above them? Surely the engineering is different and more costly than regular panels that don't need to be built to withstand cars rolling over, plus their maintenance, no?
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, former farm fields- are always going to be cheaper and more efficient.
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 for having parking in the shade. (Still more expensive than putting panels on a roof or field of course.)
"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:
This isn't really a criticism of the core idea to just say "what if somebody built it stupidly low", traffic lights have been fine my entire life and maybe some highways will have to be skipped or doubled for NASA/ military purposes.
You get two in one but for double the price of both combined and then some. Not to mention the horrible quality and durability of the two things you get.
We can't even make roads last 20 years with the most durable materials we can find. We make them out of rock and they still fall apart.
Car windshields are scratched to hell after a decade. Grocery checkout scanner windows are made of Sapphire, nearly as hard as diamond, and still need to be replaced.
Solar roads will never be a reality. Optically clear material hard and malleable enough seem a physical impossibly. Metals are the only suitable material and they cannot be made transparent due to hard physical constraints.
Solar roadways failed for the same reason Tesla will NEVER outsell gasoline cars: bad technology that's orders of magnitude worse than existing solutions.
That being said, a huge leap forward in technology would make BOTH viable.
A better road-based electricity generation plan would have been to use piezoelectric panels instead of photovoltaic ones.
You know, I always wondered why they didn't go for solar covered sidewalks, which would provide shade to pedestrians and power to everything that needs it. Roads seem like a better place for pressure-based generation (of anything, frankly).
Still, just for the enthusiasm they garnered and the continued push toward making renewable energy generation interact with the everyday, the idealists should be commended. The engineers... not as such, no.
But, silly question, knowing very little about this field, couldn't it be possible to (co)generate power from the heat and pressure that roads endure on a near-constant basis?
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 energy since it hastens breakdown. Potholes are a good example of a road surface energy absorber :) .
Solar roofs are a far better bet. Elon is onto something there, but time will tell if costs can be brought down enough. Besides the good PR, solar roofs substantially reduce heat absorbtion, important in the sunny climates solar works well in. And we have a ton of wasted roof space. Many companies would willingly allow roof panels to be put up for free if the economics for power generation were good enough.
Somewhat. OP also mentions generating energy from the pavement, which I don't think will ever be reasonable.
Solar car park covers are a great idea. Easier access than roofs, don't need to be water proof. Good cooling airflow underneath. Tend to be close to cities where power is easier to transport.
Solar parking lot covers are the best ROI solar installations I can imagine.
Surprised Telsa isn't doing this with their SuperCharger stations
I actually love seeing the "pavement lights" in NYC when I walk past them, or recognize that I'm walking under them. At this point, I know they're purely decorative, but it was a nice touch and something idealistic that left behind something cool. As far as what I was thinking on sidewalks, the other response got it right; I was thinking of putting archways and solar roofing over sidewalks. It doesn't need to be high-yield, but the benefits really sound like they outweigh the risks (as a pedestrian) - keeps the sidewalk in shade, keeps the rain and snow off, and generally would make walking a nicer experience. I've been on covered sidewalks before (including the ubiquitous scaffolds in Manhattan, Hoboken, and Jersey City - I used to aim to walk by the buildings I knew had scaffolds up when the weather was bad out), and it's a better experience than just being outside. Plus, if it's covered well, I think it'd reduce the opportunity for pedestrian vehicle accidents; just from having less possibility of people and cars interacting.
EDIT: Also, thank you for answering about the road idea, it was a thought. Too bad it doesn't work. :-P
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[ 3.5 ms ] story [ 312 ms ] threadhttps://m.youtube.com/watch?v=obS6TUVSZds
“the road was only producing half of the expected energy” - great, so just 2 km of a solar road could power the streetlights of an entire city the size of Tourouvre, 3700 people.
We shouldn’t raise the white flag so quickly. I think we need a second iteration at least before we call it a failure.
Regular roads don't fall apart in 18 months, they take 18 years (or longer) to do so.
Your county council evidently uses better contractors than mine!
More like 18 months in my region of the world.
Also I don't see how solar roads make any sense when there is so much unused roof space and parking lots. Putting panels over a parking lot is much easier since you don't have to build them to withstand many-tonne automobiles, they will always be in full sunlight instead of being covered by dirt and vehicles, and they can be angled towards the sun. Even in theory, I think solar roads are a failure.
In practice it will take many iterations to reach a point where it makes sense. Or it simply may never make sense.
The recent articles about some California farmlands being converted to solar fields does make sense. They were running out of water, but they had a lot of land to use for something.
Even if solar roads can work, there's still the problem of relatively inefficient tranfer of power over long distances. It makes little sense to spend a lot of money to make a solar road that's far away from energy consumers since a lot of the energy produced by the road will be lost in transit.
How about solar (covered) parking lots, solar roofs, etc. It makes far, far, far, far more sense.
Bitumen can also be patched and repaired relatively quickly and easily, and can use relatively simple machinery to repair/replace large sections at once. Solar panels require a lot more surface preparation, precision joining and when they break (because they will - accidents happen), leave dangerous road surfaces that cannot be easily patched/repaired.
Solar Roadways won't work with our current state of technology where we need fixed rigid panels. Something that is either a replacement for bitumen, or can be mixed into it and is able to self-assemble a current pathway might be a viable option. But we're a long ways off doing anything like that.
It was a bad idea. Even in theory. The only positive thing about it is that it captured the imagination of lots of people who know nothing about solar or roads.
The original installation in Idaho ran into predictable problems almost immediately. The much larger installations had very little justification for going forward other than it was very popular with a rather vocal group of voters. Doubt any of the politicians, celebrities, or their fans who pushed this and dumped all over those with credible objections will apologize for their part in the boondoggle.
So it's a great idea, and it's also a massive and fairly obvious failure at the same time. The message to take away from this isn't just "solar roads were a bad idea". It's that "solar roads are a bad idea, but we should keep looking at other ways to safely generate the energy we need around roads and urban passages."
Solar panels on buildings don’t need to be as rugged, don’t need to be cleaned daily, etc, and they also can be oriented towards the sun to maximize output.
Solar roads are a solution looking for a problem. I can imagine they’d be useful to squeeze out an extra few % of output in a world where everything else is covered in stationary panels, but we’re far from that so I don’t see why we should invest lots into them were the same investment would pay much more if it was about stationary panels.
What do you mean by the "sunniest parts of the planet"? You mean the deserts? Not all countries have that luxury and maintenance might prove challenging, depending on the desert.
It keeps away rain (which improves driving), doesn't expose the panels to the weight of tractors, has similar safety properties (the panels need to react quickly on any accident related impact and isolate affected circuits to avoid electrocuting passengers), and if slanted, is somewhat self-cleaning in wind or rain.
I agree though that it's nice that somebody did a field test. That idea sprang up again and again and it helps to have some real world data: people anticipated the cracking issue, 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.
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.
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...
That depends on how large the individual cells are and how they're wired up. There are panels that have a pass-through if they're occluded too much to avoid them limiting the output of other cells. It's possible that these panels had compensation mechanisms built-in.
> I'm not sure why they didn't hire an experienced engineer for this multi-million Euro project.
This isn't a few amateurs getting a construction grant and slapping the cheapest off-the-shelf panels they could find onto the pavement.
The panels were built by a French company called Wattway, a subsidiary of Colas, a large French street construction corporation. The parent company also did the construction work of actually putting these things on the street.
Apparently the "Institut National de l'Energie Solaire" was involved in this project as well, which is a public research facility (co-run by a university and the CEA, which has a budget of more than 5 billion Euros, and has a staff of 19k employees and 1200 grad + post-grad students).
That "solar road" might have been part of a research grant for all kinds of PV developments and they had to deliver it as a demonstration. That would also explain to me why they give up so easily. From the article: "Wattway [...] told Le Monde that it would not be going to market."
I'm not. Research funding is very much a zero-sum game. Because they spent that much money trying something that stupid, it's safe to say that some actual good ideas either didn't get funded or had to make do with less.
we learn more and more with every iteration
There was nothing to learn here. It was easy to predict the outcome based on well-understood models, and countless people did.
Hence the idea of dual-using those insanely large areas covered with concrete that we use as roads is a great one in principle. We do the same with rooftops already, and it works great. But roads appear to be much more challenging than rooftops.
Seems like you might get greater benefit by sacrificing yet a little more of that thing called "nature" (never heard of it before, thanks for sharing, TIL) and realize actual benefit than using the same amount of resources to solarize roads for a fraction of the benefit.
So I stand by my question.
But why?
There are plenty of arguments against it and hardly any in favor?
The problem with solar roads is it's plainly worse than the obvious alternative: putting solar panels next to roads, or above carparks.
And innovations that made them more plausible as a road surface are also going to make for a better regular road surface, or a better mounted solar panel.
[1]: https://www.youtube.com/watch?v=MQ8PPEKROz4
Maybe next they could design an airplane out of bricks. Or try using water as an automobile fuel. Or that silly experiment where they tried to make a jet fuel that wouldn't burn:
https://www.youtube.com/watch?v=Y33N0raKZBo
https://www.youtube.com/watch?v=vVyZeSgxmsw
I never understood this idea to begin with.
https://www.businessinsider.com/worlds-first-solar-road-turn...
Roads need regular resurfacing because bending the roads constantly causes them to crack and crumble.
The chinese solar road died as well. https://interestingengineering.com/solar-roadways-engineerin... (no they weren't stolen a later article reported that entire panel sections came off through traffic) https://www.scmp.com/news/china/society/article/2131241/chin...
So did the german. https://www.ksta.de/region/rhein-erft/erftstadt/feuerwehr-mu...
And I don't want to start with solar freaking roadways where normal pavement failed within a month.
(https://phys.org/news/2013-07-solar-panels-worth.html)
https://en.wikipedia.org/wiki/Self-cleaning_glass
But, practically speaking, they seem to violate the [single responsibility principle](https://en.wikipedia.org/wiki/Single_responsibility_principl...). By coupling a solar panel to a road, we're forcing the physical entity to comply with competing objectives.
Seems like the future's prone to be different, anyway. For example, how long are we going to really need roads that're driven over at-random like today? Seems like self-driving cars could be designed-and-programmed to drive over just specific parts of the road meant to handle their weight, while the gaps between those load-bearing parts can have solar panels.
if you can drive that precisely, why even put anything in the gaps?
I mean, once the road is dominated by self-driving cars, presumably we can implement new driving requirements beyond what human drivers could implement.
For roads, we might want cars to drive over load-bearing parts, if that's optimal. Or if it's more efficient to have the wear-and-tear distributed, then cars can drive in staggered formations, much like a wear-leveling strategy in solid-state drives (SSD's).
But, there's no reason to design a transportation system around the premise that self-driving cars can't control their patterns just because human-driven cars couldn't.
Which isn't to say that we should assume that self-driving cars will be perfect or infallible, just that we can assume best-effort strategies. For example, we shouldn't assume that self-driving cars would never drive over a gap with a solar panel, but we can design a system in which self-driving cars try to avoid driving over the solar panels.
I just did a quick calculation for Poland - we have 11k km electrified train tracks, with ~1.5m of space between the rails. If I calculated correctly, putting solar panels there would give us ~8-15tWh energy per year, which is 5-10% of the required electricity production for the nation.
I've never been a fan of the idea of solar roads, but solar railways might actually make sense...
I guess they might just have them at an angle, then trust the rain provide some light cleaning, while a street/rail-cleaner could go by for more thorough cleanings periodically?
I mean, I dunno what exactly their strategy is, but I'm assuming that they're not counting on a road to not get dirty. Cars leave rubber from their tires, drip oil, drop trash, etc..
https://lyricstranslate.com/en/oscar-brand-humoresque-passen...
Rail has adjacent easements. These have traditionally been used for complementary technologies, e.g., telegraph and other comms routes (which share a need for continuous rights of way, and provide a utility to the railroads themselves for communications and control services).
There are reasons you might want to avoid certain co-sitings (e.g., unarmoured petroleum or natural gas lines adjacent to rail trackage). But solar could well be a reasonable adjunct.
Solar panels above heavy vehicle traffic: Good Idea.
Solar panels below heavy vehicle traffic: Bad Idea.
If you want to solar panel anything more heavy duty than a bike path, make a roof.
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.
No they are not. Solar roads do not make sense, not for a looooong time anyway.
So far, all of the currently failed solar road projects have failed in utterly predictable ways[1][2][3], and I'm certain nothing novel has been learned.
There are so many better places to put solar panels than beneath roads. If anything they should put water pipes to utilize the heat. But solar panels, that's like trying to optimize a function for another 0.03% speed while there's still order of magnitudes of trivial improvements laying on the table elsewhere.
[1]: https://www.youtube.com/watch?v=dM50P4K9UVk
[2]: https://www.youtube.com/watch?v=7ngWjH0jdRo
[3]: https://www.youtube.com/watch?v=7ngWjH0jdRo
And hey, we can't be too hard on them for perhaps jumping on a bandwagon. Solar roads seems more plausible than food delivery service on "the blockchain".
Assume they actually made flexible panels. They'd still have the issue of the abysmal efficiency due to the inevitable grinding of the surface and dirt filling up the cracks. You'd need frequent washing of the roads to keep them clean. Was that included in the energy projections?
Missed by most people is that roads flex under the weight. (Stand next to the train tracks when a train goes by, you'll be startled at how much the ground moves.) Flexing of the roads it the primary cause of road maintenance - cracking and crumbling.
Silicon chips in the roadbed, wires, pipes, etc, are all very vulnerable to cracking under bending loads. Putting water pipes in the roads mean you'll get innumerable leaks in short order.
[1] https://www.theregister.co.uk/2015/05/26/pavegen_the_company...
That said, we have the technology to make flexible pipes. It'd still be a pretty dumb idea, but at least a few order of magnitude less dumb than these solar roads.
Road surfaces have pretty specific and harsh needs, which currently can be mostly solved with really cheap solutions (concrete/asphalt). Photovoltaic cells on the other hand are comparably very expensive and fragile.
Surely, land can't be that expensive in most places that it makes sense to use the road surface, compared to say roofs.
I think what we might gain from this solar road experiment will be related to material science in the area of solar panels. Just look at mobile phones; surely the transition from old plastic in front of LCDs to "gorilla" glass has benefited other use cases. I'm just guessing here, but I bet there is something to learn which can be applied elsewhere.
I think flying cars are absolutely moronic and completely impractical. But who knows... maybe the brainpower spent trying to make them work will result in better traffic management or people transportation elsewhere.
Airplanes are not amenable to hackers designing them. Getting one to fly required a directed engineering effort, with a series of prototypes each targeted at solving a specific problem. I think it was the first such project that did so.
The Wrights are often dismissed as "bicycle mechanics", but if you take a closer look they were very competent engineers.
(The difference between an engineer and a mechanic is math. The Wrights did not try random things, they used math to arrive at solutions.)
There's an immensely successful experimental aircraft industry, and I'm not just talking about people who are (successfully) building human-scale vtol drones.
The FAA won't let you fly it until an engineer goes over your design. For very good reason.
An unbalanced airplane isn't going to fly, and one that isn't strong enough will fold up on you. There's a thin line between strong enough to hold together and light enough to get off the ground - and you cannot find that without math.
There were many hacker airplanes before the Wrights. They were all too heavy, too underpowered, too unstable, and too weak to fly. The Wrights, with math, solved those problems.
Solar panels need to be oriented towards the sun to maximize energy, and need to get as much sun going through the glass to the panel as possible. You basically end up multiplying many variables together to get the end efficiency, and we're actively degrading 3 by a significant degree by adjusting the glass/plastic to withstand the weight of cars and semis, scratching the surface over time with the dust and sand, and mounting them flat.
Roads need to be cheap to install, need to be long lasting, and need to assist vehicles in stopping quickly. I'd love to know the difference in stopping distance and coefficient of friction between this and traditional roads.
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 that this wasn't sound from even basic engineering.
I wouldn't call it a scam if they were honest about this. If they said "yes we need to do more testing" and "this test will help us figure those things it". But they didn't even do the background research. They called everyone that did may sayers. There's a reason only the IFLS type crowd liked them and not actual engineers.
I'm all in favor of doing hard tasks. Using government money to take risks in science and engineering. That's something we need to strive for. But things like this make it harder to get support for that because this was a joke from the beginning. Experts knew it was a scam from the get go.
This project was probably a poor use of funds (compared to other options), but the effort may have advanced our knowledge just a bit.
Science should at the very least be informed guesswork - if you don't start with a reasonable hypothesis and don't update your hypothesis in light of the evidence, it's just alchemy.
So the idea isn't too crazy, it seems. Maybe it is unsuitable for heavy vehicles, or in areas where particulate is more likely to collect and affect the light gathering; but to some degree it can be successful.
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.
Be very wary of motivated reasoning.
With say a probably still generous 6x derating, it would mean 2.94/6/11.45 = 4% of electricity production.
If you manage to avoid road solar tax (say by putting it above the road), it gets to about 25% of electricity production. Assuming a less pessimistic capacity factor of say 16% [1] gives 32% of electric production. Build a 3x wide solar cover over the interstates and .. use your imagination.
[1] http://euanmearns.com/solar-pv-capacity-factors-in-the-us-th...
There are 4,000,000km of paved roads. (https://www.roadtraffic-technology.com/features/featurethe-w...)
That puts your estimate out by a factor of maybe 25 or more (depending on road width) if all roads are converted to solar. And that's before the other paved areas like parking lots.
I'm not advocating solar roads. They're a strange idea with many, many flaws, but the inefficiency aspect isn't one of them. If you want to generate lots of electricity with solar you can have one very efficient array, or lots of inefficient arrays. Solar roads are the inefficient one.
Right now we have either small "local" productions with "local " consumption (that works well as there is little distance to be covered) or "large" production concentrated on one site and with tension raised to thousands of volts to allow delivvery to the final user.
A "solar" road would probably make sense only in urban areas (where there would be other issues, like - say - shadow from buildings, less time of road free of vehicles, etc.) to avoid the issue of transporting the energy for long distances to the final users (or have a huge loss in the process).
Go, fire up your favourite sattelite image service and check out how much of a typical urban area is really sunlit streets or parking lots. Bonus points for images where the cars that are present are on it. Ah and in an urban environment count shadows in. And quarter whatever figure you got because of dirt, abrasion and failure.
And now compare them to the areas of rooftops you find. Go ahead and do it.
My 5 min of reading the article and thinking about it idea is thus:
A slanted roof angled to shade and water/snow protect the road, shedding runoff in to a gravel area beside the road with drainage considerations accounted for. The far side might have some sort of attached tarp over part of it, and there'd be a gap between top of said tarp and the bottom of the panel roof. That would promote heat-stack ventilation along the underside of the panels and thus also SOME cooling.
Benefits:
- Reduced evaporation losses.
- Extant rights of way / property rights.
- Extant technical infrastruction, including power transmission for pumps, etc.
Not that this is the only siting location to consider, but it's a reasonable candidate.
Shade awnings over car parks another.
The challenge with solar power really isn't sufficient area for siting. It's low-cost installation and low-disturbance environments which ensure long panel life and low maintenance costs.
Solar panels have a useful lifetime of about 20 years, due to 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. NREL (the National Renewable Energy Laboratory) in Colorado have published research on this.
Engineering low-cost, long-lived, readily installable and replaceable panels would be a generally advisable research direction. Looking for extreme siting locations (e.g., high-traffic highways, or even sidewalks), or even, counterintuitively, greater efficiency, is relatively unimportant as compared to total costs and lifetime.
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 in contact with the cell? Could there be something that was effectively a replaceable capture top surface possibly with an air gap above the actual photovoltaic cells?
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 effective lifetime of 20-30 years.
Rough number, and actual results depend on specific siting characteristics and events. A tornado passing overhead, sandstorm, or very severe hail, may significantly negatively affect experienced lifetime.
However the point remains that 20-25 years is the standard rated lifetime for planning and estimating purposes.
https://www.nrel.gov/pv/lifetime.html
http://www.nrel.gov/docs/fy12osti/51664.pdf
I mean, the hell? I wouldn't put solar panels in a playground, because I would assume 50 pound children running around would destroy them. Obviously, motor vehicles will. And very quickly.
Is this some sort of insane joke?
They were warned about this.
Spending the money to solve problems on your first run is likely to not actually solve all of them.
Then again, this could be a bold exercise in fraud and/or incompetence.
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...).
They built a Minimum Viable Product for a trial and found out that it wasn't actually viable and didn't provide the hoped for value. They probably also learned a lot with real world experience (that they wouldn't have been sure to have in a staged setup) and may come back with something different in the future.
Personally I'd be curious about the math on how much these panels pick up, whether some kind of contactless power transmission would be viable at highway speeds, and whether in 15-20 years we'll see interstates paved with these providing trickle power to fully automated electric trucks running as "road trains" across the country.
Still, power sourced from solar or wind in general and adequate to offset some of the "maintain speed" level of power draw? That seems more likely. If you have some way to provide maintenance levels of power during movement that may mean a significant savings in battery weight and overall cost, and if you don't think that matters take a look at the skirts under a lot of trucks designed to reduce drag.
The sweet spot for solar roads would be in places where the generation benefit outweighed the extra cost when a road was being redone anyway - and even then only if the materials were up to the task.
When you want to launch a new technology it's better to have it do better than expected than to have it run into 'unexpected' problems.
I'm leaning toward scam, because if it can't handle leaves, it can't handle anything.
Engineers herded along by management.
I have come across quite a few “green” initiatives over the past several years which are extremely questionable in their technicals - and all are taking public money, mostly from European Development Funds in the EU, and from similar bodies elsewhere.
They are usually highly visible, buzzword bingo initiatives. You see these projects in the press - a group grinning in hard hats, a colourful initiative behind them. You go back a few years later and it’s tape and barriers and broken glass and danger signs.
Whether folks start with good intentions but then move on, or don’t have adequate plans for maintenance (which then makes one wonder why funding was granted in first place), or simply see an opportunity to extract wealth from a public body, I don’t know.
An anecdote: a service station near my home in north wales proudly announced that they had received a grant to put on a turf roof, solar and wind power. EU funding. Three years on, and they’ve just announced that they’ve received a grant to do exactly the same thing. Plumbing the Europa site shows that the previous grant was paid, and the project reported as completed - but they never did a thing. I’ve seen the same cycle being pulled elsewhere.
There is such a push for governments to be visibly green that they are spending money on highly visible nonsense. The current elected power gets the boost for snipping the ribbon and providing the funding. Their successor gets a beating over the wasteful failed project.
There are good green initiatives happening, but it’s usually where nobody is looking.
This should be reported to media, police or both - this is fraud.
We're the country of ruthless self deprecation coupled with perfectionist universalism.
I hope something was learnt here (other than learning not to do it again), and I'm absolutely confident the people who cluelessly pushed for it will go on their public careers unaffected while the innocents are punished.
We've done more insane stuff and survived to tell the tale.
But really, PV in Normandy ? Come oooooon....
I wonder if there traits make you good at nuclear power. Perfectionism and ruthless self criticism seem like they'd engender the kind of thorough and methodological approach that keeps reactors from getting explody.
The Russian "can't duck it, fuck it" attitude seems to have the opposite effect judging from the Geiger counter readings.
I'm afraid not - the trials played out exactly as the naysayers predicted. Most of the panels cracked under load and failed due to water ingress; those that didn't became woefully inefficient due to soiling. They were dangerously slippery even in ideal conditions, they cost much more than a conventional rooftop installation and they never generated as much electricity as a rooftop installation even when they were brand new.
The whole exercise was a complete waste of time and money.
I don't know how reliable they are, but solar-powered streetlights are already common in some areas --- and being mounted high above on the lights themselves, the panels are far less likely to be damaged.
I'm going to bet they said that after the check cleared.
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 sense.
Now, of course, we may not get close enough to that limit for this to make sense, cells may be too fragile for mounting in a road, there may be plenty of more profitable places to put solar cells, etc, etc, but that isn’t guaranteed, and we can’t tell without experimenting.
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.
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.
So many things are wrong with using solar road surfaces that it’s hard to make them look viable even if the panels cost nothing. Because that means electricity is worth very little, and you still need to integrate them into the road surface which costs money.
Going down that road leads to solar power satellites, not solar roadways.
1. Solar roadways is a terrible idea that will never be a good idea. It is strictly worse than building a roof over the road and putting solar panels on that.
2. Roughly half the renewable energy on earth comes from decaying isotopes and half comes from sunlight. If humans want more than that, they'll basically need to get it from sunlight not hitting the earth i.e. solar power satellites. That is a road that we'll eventually go down, but not for quite some time.
Solar roads has the distinct advantage over covering all the roads in that it's not an eye sore and fits more seamlessly in the scenario we figure out the engineering.
There's this idea in economics called opportunity cost. The simple version is that if we fund bad ideas that can't possibly be good, we lose out on the good ideas we could have funded but didn't.
This is the reason you don't heat your house by burning paper money. You'd rather have rent and groceries and heat instead of really economically inefficient heat.
Roads take up space, cost money to build and maintain. If you build it next to the road the road need twice the amount of space and still require the space, construction and material for the actually road. If you build it above the road you get all the issue of overhead roof on a road (trees that fall on it, wind, height limitation).
In addition to saving money by not actually building a normal road, the idea in most of solar roads projects is that it combines the work of putting internet and power cables into the ground.
That it currently do not work economically is the issue that the article showcase. Maybe it will never work and it always will be cheaper to simply build the road with current construction methods, put internet/power cables under it, buy large lands (farming land?) and construct regular solar parks.
Other concept of combining solar panels and building materials that is argued as more cost effective are roofs on houses. Same concept as solar road, ie that you get a roof and a solar panel in one without spending the work and material for both, but I have no idea if the economics is better than solar parks or if it is cheaper to just build normal roofs and go the route of getting land and building solar parks separately.
It's more than that. We simply don't live in a world where physics is in favor for doing this.
Many people have done more than back of the envelope calculations to show this simply was a non starter.
Those (people who took money to build ) push this idea are either ignorant at best and dishonest at worst.
It only makes sense to start thinking about sidewalks once you've covered all the roofs, which are way better in every sense.
So the sidewalk would need to be just as strong as the road.
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.
I don't think the study invalidates parents claim, if anything it more it less supports it.
Also I have seen high hees being abused by walking mostly on the heel.
https://en.solaroad.nl/wp-content/uploads/sites/2/prf1-ENG-S...
Why can't they just work on something that makes sense?
It just does not make sense.
Under the road is literally the only option, and it's a terrible option at that. Rooftops - or better yet, former farm fields- are always going to be cheaper and more efficient.
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 for having parking in the shade. (Still more expensive than putting panels on a roof or field of course.)
https://www.cbs58.com/news/truck-wedged-under-bridge-shuts-d...
We can't even make roads last 20 years with the most durable materials we can find. We make them out of rock and they still fall apart.
Car windshields are scratched to hell after a decade. Grocery checkout scanner windows are made of Sapphire, nearly as hard as diamond, and still need to be replaced.
Solar roads will never be a reality. Optically clear material hard and malleable enough seem a physical impossibly. Metals are the only suitable material and they cannot be made transparent due to hard physical constraints.
That being said, a huge leap forward in technology would make BOTH viable.
A better road-based electricity generation plan would have been to use piezoelectric panels instead of photovoltaic ones.
Still, just for the enthusiasm they garnered and the continued push toward making renewable energy generation interact with the everyday, the idealists should be commended. The engineers... not as such, no.
But, silly question, knowing very little about this field, couldn't it be possible to (co)generate power from the heat and pressure that roads endure on a near-constant basis?
Roads don't absorb enough energy to generate power, they're not flexible enough. They're designed to not absorb energy since it hastens breakdown. Potholes are a good example of a road surface energy absorber :) .
Solar roofs are a far better bet. Elon is onto something there, but time will tell if costs can be brought down enough. Besides the good PR, solar roofs substantially reduce heat absorbtion, important in the sunny climates solar works well in. And we have a ton of wasted roof space. Many companies would willingly allow roof panels to be put up for free if the economics for power generation were good enough.
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.
Solar car park covers are a great idea. Easier access than roofs, don't need to be water proof. Good cooling airflow underneath. Tend to be close to cities where power is easier to transport.
Solar parking lot covers are the best ROI solar installations I can imagine.
Surprised Telsa isn't doing this with their SuperCharger stations
EDIT: Also, thank you for answering about the road idea, it was a thought. Too bad it doesn't work. :-P
That would simply inefficiently make the vehicles less efficient.
Why not just build a solar ceilling?