France To Pave 1000km of Road With Solar Panels (solarcrunch.org)

An anonymous reader writes: France is planning on a project to build 1000 kilometers of road with specially designed solar panels. This project will supply 5 million people in France with electricity if it is successful. Though many solar experts are skeptical of this project, the French government has given the go-ahead to this venture. According to France's minister of ecology and energy, Ségolène Royal, the tender for this project is already issued under the "Positive Energy" initiative and the test for the solar panels will begin by this spring.The photo voltaic solar panels called "Wattway" which will be used in the project are jointly developed by the French infrastructure firm "Colas" and the National Institute for Solar Energy. The specialty of "Wattway" is that its very sturdy and can let heavy trucks pass over it, also offering a good grip to avoid an accident. Interestingly, this project will not remove road surfaces but instead, the solar panels will be glued to the existing pavement.

Comments

What could go wrong

[kamapuaa]

So basically the plan is to cover the pavement with glass, that will need to stay clean to let the sunlight through. I see no possible problem with any of this.

Re:What could go wrong

[fustakrakich]

Yeah really, they should give the road a piezoelectric surface. Put the solar on the shoulder.

Re:What could go wrong

[Rei]

Meh, there's a solar bike path in the Netherlands and they don't seem to have excessive problems with dirt. Because rain exists. They got significantly higher generation than they were expecting - only about 1/3rd less than what you'd expect from rooftop mounted panels.

I too have criticisms of the "Solar Freaking Roadways", but let's start with common criticisms that aren't well grounded:

1) They'll scratch up: first off scratches can reduce light transmission but solar panels don't require good "optical quality", only transmission; the light is free to scatter on its way in. It's the same thing that applies to greenhouses - you may have noticed that many greenhouses use "fogged" plastic that you can't see through, yet still lets the vast majority of the light in (in that case, the scattering is actually seen as advantageous). Beyond that, in the case of roadways, I'd think it a given that they'd coat them with a an anti-scratch coat (aka harder than Mohs 7 / quartz sand, the hardest common natural material))

2) Traction: Traction glass exists - it's just surface texturing. They use it for semi-transparent flooring, it's nothing special.

3) "Glass would break and then shred tires": It's easy to make glass bear purely compressive loads (solid objects on both sides of it) without fracture - that's what it's best at. It's shear and tensile loads that glass is bad at, but these aren't applicable when it's flat on a hard surface. And lamination, like in windshields, prevents dangerous shards from coming off in the event of a fracture. This is not an actual limitation.

3) Shadowing: Go to Google Maps satellite view and look up random roads. The overwhelming majority of road surface is completely unshadowed at any point in time. Even in-city roads are overwhelmingly unshadowed. Shadows are practically irrelevant in the countryside except in wooded areas.

4) Costs: The costs of the materials for a road are a minority of the costs of the project, and continue to be a minority of the cost of the project under any realistic pricing for large-scale production of paving panels. A key driver for affordability, however, would be scale: this means large scale production (so road panels are similarly priced to rooftop panels plus the extra glass costs) and continuous paving systems. Anything smaller scale would have elevated costs.

5) "They'd be better on roofs": the main problem with roof installations is there is no way to do mass-scale continuous install (the sort of possibility that paving gives). Each roof has to be handled on its own, with its own engineering issues, with its own project overhead, its own inverters, etc. The key issue to cost reduction these days is getting rid of the overhead; panel production costs themselves have gotten quite low and keep going down. Furthermore, with a road you get "two birds with one stone" - a driving surface and a power generation surface built at the same time in the same space, sharing the same project overhead. It's fine to sacrifice some panel efficiency to glass, shadows, dirt, etc if it reduces your overhead costs.

All of this is not to say that I think they're inherently some sort of great idea that we should dump billions of USD into right this moment I simply think that they do deserve more development and testing, and I have issues with some of the criticisms that have been levied. On the other hand, I do have some issues with the "solar freakin' roadways" people. Number one on my list is the snow-melting concept. It takes five minutes to run the numbers on that and find that it takes way more energy than could ever be considered reasonable. You could melt thin layers of frost off the surface, but nothing of any relevant mass.

If one wants to pursue an anti-snow approach, my personal alternative is having an air bl

Re:What could go wrong

[Rei]

I assume that's a joke.

It's one of the "solar freaking roadways" peoples' concepts that makes me sigh out loud, even though I actually think that the concept of solar paving warrants further research. Having roads have "give" and generating power from that is like making cars constantly have to drive uphill. You're just stealing energy from the cars. Very inefficiently.

Re:What could go wrong

[Rei]

Even in heavy traffic, the overwhelming majority of the road is exposed. And yes, that's the 405, in a high traffic area.

Re:What could go wrong

[MobileTatsu-NJG]

It's a good thing that this has been tested before they asked you.

http://thinkprogress.org/clima...

Re:What could go wrong

[ShanghaiBill]

The vehicle-covered to not covered duty cycle on a rural highway is pretty high.

The duty cycle on rooftops is a lot better, plus there are no trucks driving over them there. I could see looking for alternatives once all the rooftops are full, but they are less than 1% covered so far. Ségolène Royal has a long history of advocating crazy policies with little thought about how to pay for them.

Re:What could go wrong

[ShanghaiBill]

I was just going to say that we, here in LA, were going to try this on the 405, but it's always covered with cars.

Here in San Jose, we have solar panels over many parking lots. They generate electricity while providing shade for the cars.

Re:What could go wrong

[currently_awake]

On most highways the cars only cover about 20% of the pavement. Unfortunately that's as good as this idea gets. It only makes sense to put solar panels where the cost of the panel is less than the value of the electricity, and roads isn't one of those places (armoured glass is expensive, they get scratched and dirty). Better places: a roof over the road (massive reduction in snow/ice removal costs, you can use cheap solar panels), on house roofs (you can use cheap solar panels), deserts (cheap land, lots of sun, cheap panels).

Re:What could go wrong

[jblues]

The duty cycle on rooftops is a lot better, plus there are no trucks driving over them there.

Trucks are constantly driving over my roof, you insensitive clod. I'm one of the last surviving trolls, and live under a (now solar paved) bridge.

Re:What could go wrong

[Rei]

Like how hold concrete becomes slippery? Yep, just like with concrete, you need to resurface. But one expects them to use anti-scratch coatings, which would significantly reduce the rate of wear. The aggregate in typical concrete can be up to Mohs 7, but the cement is only Mohs 2-5. Raw unprotected glass is Mohs 5-6,5, but scratch resistant coatings can raise it to over 7 to avoid being scratched by quartz sand.

Re:What could go wrong

[vel-ex-tech]

But why roads? Of all the places we could put solar panels, why roads? I mean, I just can't comprehend how this is even a proposal in the first place. I haven't been able to since the first time I heard about the idea, and I still can't. There are too many things that can go wrong, too much engineering involved. It's like a Rube Goldberg machine. The solar panels are better on my roof and in my backyard. If we want solar power from roads, then why not just mount the panels on poles along the roadway?

Re:What could go wrong

[Elfich47]

Any given winter will have 50-100 freeze thaw cycles. Once you suggested air blower fails all of the nooks and crannies will get filled with snow and then the freeze/melt expansion/contraction cycle of water will destroy the piece of equipment. I have yet to see a piece of equipment that can stand up to repeated freeze/thaw cycles from a New England winter.

Next up: Snow plows and everything the snow plow pushes in-front of it. A snow plow lumbering along at 20 miles per hour can clear a path 15' wide and a foot deep (often more if it is the truck at the end of plow gang). Any odd ball things in the path of the plow get thrown aside - car parts, baby carriages, clothing, building supplies, will all be thrown aside.

Any portion of the solar panel that doesn't give a clean path to the plow will be destroyed. Any thing dragged along by the snow plow will leave tracks until it is thrown away. "Textured" glass designed to give better traction will get chewed on by the snow plows. If the snow plows leave chips, cracks or divots in the glass: the freeze/thaw cycle of water will attack those imperfections and widen them over the course of a winter.

Until someone demonstrated the ability of those things to survive several seasons of snow plows and freeze/thaw cycles I don't expect to see them where I live. Roadways are designed to be robust and not need a lot of maintenance (exceptions for specific specialty items are to be expected- bridges and tunnels come to mind).

Re: What could go wrong

[guruevi]

The problem with putting regular panels next to the road is space especially in rural areas where the roads are often already cutting through previous private lands captured by the government. Capturing more land for use by city slickers' energy production (smart farmers will often already have solar panels) will not go over well and may be more expensive in buyouts and legal issues than developing brand new technology.

Re:What could go wrong

[Rei]

Unfortunately, as we know, there's absolutely no ways known to man to texture glass that could be fitted onto a truck.

Re: What could go wrong

[orlanz]

We could put it on all downhills in a certain grade range. Steal power from the brakes.

Also local roads with traffic that burn gas inefficiently should be ok too. They don't run the engine efficiently so stealing some excess power should be ok.

Re:What could go wrong

[jblues]

Yup, that was part of the joke. I'm a funny troll. It is an evolutionary adaption, like moving to Twitter.

Re:What could go wrong

[Kjella]

A bike lane is nothing like a 50 ton truck in an emergency stop. Asphalt is extremely simple and can't be damaged in any meaningful way. Texturing and coating wears off, asphalt just wears down and if you're going to provide lots of traction as you must then there will be lots of wear. And you can't just make the wear layer thicker without reducing the optical properties. And if the foundation isn't rock solid these slabs are going to start wobbling and crack up like driving over giant tiles. And you can't rally patch a hole with a bit of cheap asphalt, the whole tile must out and be replaced. Cost is the big killer, it's why we don't use more solar today it's not like we covered everything else in solar panels and roads are our last resort. So they produce 1/3rd less energy, involve a ton of tempered, textured, laminated glass encased in concrete with high maintenance and low robustness. Where can I sign up?

Re:What could go wrong

[Firethorn]

A solar car port makes a lot of sense if you're going to be making a car port* anyways because the solar panels can be the roof itself. The displacement of the roofing materials makes the solar panels a relatively cheap upgrade.

As for 6x the cost of 'standard electricity' - you need to update your figures and realize that not all electricity is that cheap. It's under 2X for competently done installs even before rebates and such.

If you have semi-frequent outages the reduction in generator load(during the day at least), makes it even more economical.

*In this case a 'car port' is a partial shelter option for a car. IE a roof, maybe a side panel. Intended to keep the rain and sun off of cars in areas normally hotter than temperate. Not a complete shelter.

Re:What could go wrong

[PopeRatzo]

Why would you want to spoil a perfectly good Slashdot comment anti-renewable energy freakout by introducing facts?

People here would rather talk about practical technology like a manned mission to Phobos. Solar energy is just a fantasy that can't possibly ever work.

Re:What could go wrong

[geoskd]

The duty cycle on rooftops is a lot better

True but with rooftop, you pretty much need one inverter per rooftop, which adds substantial amounts to the cost. With these paved roadways, you could probably get the equivalent of 10-20 rooftops with only one inverter, thus significantly reducing the cost of installation. Plus, under most circumstances, installers wont fall off the roadway, thus creating a *very* expensive insurance liability. The cost of liability insurance is a very large (~20%) part of the cost a given rooftop solar installation. Playing around on roofs tends to kill and maim people with rather frightening frequency.

Re:What could go wrong

[Jeremi]

I see no possible problem with any of this.

I don't either. Either this road proves workable, in which case the world now has access to a new, proven technology -- or it turns out not to be workable, in which case the technology is a failure but all the costs will be paid by the French.

It's not quite win/win, but at least it's win/neutral.

Re:What could go wrong

[hey!]

Well, golly, I'm an engineer too, so I know engineers aren't infallible. In fact we can be downright stupid. But usually not so stupid that people outside our field understand problems in our field better than we do.

Re:What could go wrong

[zieroh]

The duty cycle on rooftops is a lot better, plus there are no trucks driving over them there.

There are a lot of naysayers here worked up about the potential for cars to block the sunlight. To which I say So What? It's an experiment. Someone is trying a different approach to solar, and that's actually a good thing. While I can think of potential drawbacks to this approach, I can also think of quite a few potential advantages. The exact ratio of disadvantages to advantages is the important part here. Pointing out the obvious -- that cars will occasionally block some of the light -- doesn't serve any useful function.

Again, it's an experiment. Accept that you might not actually know everything.

Re:What could go wrong

[gl4ss]

and in both cases we already know it will not pay for itself, WHILE if you just put them even upright at the side of the road, it would pay for itself(and reduce road noise).

oh and it would be cheaper.

solar freaking roadways is an extreme case of a solution looking for a problem. even if you COULD make the roads out of it, it would still make no sense to do so before all the sides of the roads, roofs and buildings were full of panels. it's basically the LAST place you want to put solar panels on, due to various reasons.

I guess you could use them as detectors for tank movements or some shit like that though..

Re: What could go wrong

[Type44Q]

"Freeway" has a specific meaning that's different than "highway" and "expressway." While i wouldnt be surprised if the term originated in California, it's definitely not an "ism."

Re:What could go wrong

[TheReaperD]

Actually, we don't "know" if they will or will not pay for themselves. We have two, or more sets of numbers, some from the makers of the solar products and some from companies such as BP and Shell. There's really no one involved that can be considered impartial so the best way to solve it is lay some down, get the numbers and see if anyone is right. With the ones here in the US (I'm not familiar with the French design) the panels may be still be worthwhile even if all they do is break even due to their ability to deice and detect and report road hazards as well as lay cable and piping without having to redig every time.

Re:What could go wrong

[Narcocide]

No, more likely they're doing this because nobody wanted to give up any of their private land on the sides of the roads, so using the road itself for solar paneling is an infinitely more efficient use of space, because the roads themselves are public land by definition, and paving them with solar panels takes up exactly 0 extra real estate.

Re:What could go wrong

[Captain Hook]

Personally, if I was going to harness kilometers of road surface for energy generation, I think I'd go for embedding pipes under the surface and pumping liquid through them to move the heat back to a Stirling engine.

Re:What could go wrong

[AmiMoJo]

The surface will be much harder than asphalt, and even when it does eventually wear it should be easier to replace as you just lift off the old slab and put a new one down.

In fact some places have been doing that for many decades with concrete slabs and later asphalt slabs. The problem is that the joints are never that smooth and end up being noisy, which is why it tends to be limited to roads far from where people live.

Re:What could go wrong

[wienerschnizzel]

1) They'll scratch up: first off scratches can reduce light transmission but solar panels don't require good "optical quality", only transmission; the light is free to scatter on its way in. It's the same thing that applies to greenhouses - you may have noticed that many greenhouses use "fogged" plastic that you can't see through, yet still lets the vast majority of the light in (in that case, the scattering is actually seen as advantageous). Beyond that, in the case of roadways, I'd think it a given that they'd coat them with a an anti-scratch coat (aka harder than Mohs 7 / quartz sand, the hardest common natural material))

2) Traction: Traction glass exists - it's just surface texturing. They use it for semi-transparent flooring, it's nothing special.

A thin flat clean surface is the most efficient cover for the cells. Any deviation will decrease the efficiency. You are suggesting a rough thick 'milky' material with scratches on it. It will scatter a lot of the light away from the cells. Greenhouses are not a good counterexample as they are not built for *maximum* throughput, just for one that delivers a stable 90F atmosphere inside.

3) "Glass would break and then shred tires": It's easy to make glass bear purely compressive loads (solid objects on both sides of it) without fracture - that's what it's best at. It's shear and tensile loads that glass is bad at, but these aren't applicable when it's flat on a hard surface. And lamination, like in windshields, prevents dangerous shards from coming off in the event of a fracture. This is not an actual limitation.

But the glass will not bear purely compressive loads. There will be impact forces of heavy objects falling on it at high speed, cars driving over hard pointy objects lying on the road (stones) and ice expanding within the grooves between the tiles and underneath them (this is the greatest nemesis of the asphalt road).

3) Shadowing: Go to Google Maps satellite view and look up random roads. The overwhelming majority of road surface is completely unshadowed at any point in time. Even in-city roads are overwhelmingly unshadowed. Shadows are practically irrelevant in the countryside except in wooded areas.

Fair enough.

4) Costs: The costs of the materials for a road are a minority of the costs of the project, and continue to be a minority of the cost of the project under any realistic pricing for large-scale production of paving panels. A key driver for affordability, however, would be scale: this means large scale production (so road panels are similarly priced to rooftop panels plus the extra glass costs) and continuous paving systems. Anything smaller scale would have elevated costs.

Two problems - complexity and maintenance. A solar road is orders of magnitude more complex than a regular road - first it will drive up the cost because it's not as simple as pressing a malleable material onto a rocky surface. You will need to connect the panels and lead wiring, construct maintenance access points, test the functionality. Maintenance will be a major pain in the ass. And for all of this you will have to hire more expensive technicians than what you need for regular roads. Scale does not help too much either. Regular solar panels are already mass produced and are orders of magnitude more expensive than asphalt. Even if you cut the price in half somehow, it will remain orders of magnitude higher than regular road surface.

5) "They'd be better on roofs": the main problem with roof installations is there is no way to do mass-scale continuous install (the sort of possibility that paving gives). Each roof has to be handled on its own, with its own engineering issues, with its own project overhead, its own inverters, etc. The key issue to cost reduction these days is getting rid of the overhead; panel production costs themselves have gotten quite low and keep going

Re:What could go wrong

[Bob the Super Hamste]

Also remoteness is a factor. I have a property up in northern Minnesota that I will likely at some point put a cabin up on. My options for power are a generator, pay for a several hundred meter run (about 500) and a transformer, or solar/wind plus battery storage. Generators seem to come in 2 forms, cheap and noisy, or expensive and quiet and that ignores the fuel cost and other maintenance. If I wanted to get connected to the grid it would probably be in the $10,000-$15,000 range for the run and transformer plus the monthly connection fee. That leaves solar/wind as a a fairly cost effective option. As it wouldn't be used all the so time I could have a fairly low generating capacity (maybe a couple of KW) but a higher than average reserve capacity. When the site isn't being used the solar/wind can charge a battery bank.

Re:What could go wrong

[rhazz]

1,000 KM of solar panels to provide power for 5 million people does not sound like an experiment. It sounds more like a huge infrastructure investment using a technology that currently has only been implemented at a length of 100 meters on a pedestrian/cyclist pathway, and that implementation was done by a completely different company with a different product. Surely just a few kilometers would be more appropriate for an experiment. I would hope they are implementing the project with a drawn out introduction phase that will test the product at a much reduced scale for several years.

Re:What could go wrong

[angel'o'sphere]

We are taking about "highways" not about roads in a street. On a highway you have a about 1 car every 100meter, or less. I usually drive km's on french highways without even seeing a car.

Re:What could go wrong

[angel'o'sphere]

it's basically the LAST place you want to put solar panels on, due to various reasons.
There is a thing between your two ears, which should be switched on before writing/talking.

Simple hint: the houses and hence the roofs you are talking about are: private owned. The government has no simple way of "forcing" citizens to build solar plants on such roofs.

Secondly: if citizens would set up solar plants on the roof, everyone would have a single connection to the grid, with a single feed in and extraction metering.

OTOH: the road is public owned. The "owner", may it be a town or a a department, can put on that road what ever he wants.

Finally: to connect a piece of the road to the grid, you simply decide where a good distance to the relevant grid is, e.g. instead of connection it to a distribution grid like a roof, you connect it to a transport grid. And: you only feed into the grid and never draw energy from it.
So: you have far less and far simpler connection points to a higher level grid!!!

So, IFTFY: it's basically the L^HA^HS^HT^H FIRST place you want to put solar panels on, due to various reasons. However I had considered to place them on a kind of roof or noise protection walls along the road instead trying a pavement.

Re:What could go wrong

[silentcoder]

>AC also only uses one cable and the ground for the other.

Maybe in the US it does, but here it definitely does not. Possibly because we use an earth leakage system with three cables for AC. Earth leakage is much safer - almost all electrocutions have the ground as the return part of the circuit so an earth leakage system means those are virtually impossible. The US I understand uses fuse boxes but we use circuit-breakers and earth leakage. On the other hand, our home power is twice the voltage of US systems so that is probably what justifies using more expensive safety systems - the risk when you get shocked is much higher at 220V.

Re:What could go wrong

[hattig]

I presume the snow plow could also leave about an inch of snow and have an integrated blower or series of brushes to blow/sweep the remaining snow away.

Or that one inch of snow is drivable, whereas what was there before wasn't.

Or these panels will not be used in areas where snow really happens, and road salt/grit is enough for cold nights.

Re: What could go wrong

[Joce640k]

... assuming people always drive on the same side of the road)

Well, yes... only if we assume that.

Re:What could go wrong

[silentcoder]

I would say for the average shack dweller, that's the least of their downsides.

tl;dr

[Anonymous Coward]

RRV #632 for the tech. For the political sorts, this is what happens when you have a stupid EU policy requiring the state to pay private companies to build infrastructure rather than employing their own talent.

Why not a roof?

[JoeMerchant]

Wouldn't it be more effective to build a "solar roof" over the highway, shading motorists during the hottest parts of the day, angling the panels to maximize insolation at the latitude, and for f's sake: not having to make them sturdy enough and grippy enough to safely drive trucks on them?

How long will this roadway last, and what will be the replacement cost? I mean, if this miracle surface can stop potholes from forming, then, yeah, let's put it everywhere, but I'm not feeling like that is the case.

Re:Why not a roof?

[aaarrrgggh]

That was my first reaction as well, but a roof structure would run about $4-5/watt for the system, with panels about 35% of the cost.

Assuming the roadway is about half the efficiency at peak output, cars traveling at 60mph and keeping 6 car lengths minimum between themselves, twice the cell cost but no superstructure... Your installed cost per watt is 70%, with a 15% performance penalty, or a pro-rata $3.3/W.

Granted upkeep will be higher, and life likely lower, but might actually work.

Re:Why not a roof?

[rmdingler]

Of course, there's traction and such to consider.

Why?

[Dereck1701]

I can't really see the reasoning behind this, it would be far easier, more efficient, quicker and cost effective to put panels along the roadsides, next to substations on the sides of buildings, on roofs, or practically anywhere but on roads. Until they can lay solar panels like they do pavement for virtually the same cost as pavement there really isn't much point when there are SOOOOOOO many other viable locations.

Re:Why?

[SlowCanuck]

Exactly what I was going to say. The "Carbon Footprint" of a solar road way is going to be enormous!! Maintenance, initial design, and not to mention the other things brought up, need to be strong to carry vehicles, and grippy. People do not realize that glass reacts to sun and actually become brittle. Just Glad it is France and not somewhere in Canada!!

Thanks France

[Kohath]

I don't think this will work, but I hope it does. I'm glad the French are paying to find out instead of us.

I suspect the initial cost (or yearly amortization of that cost) and ongoing maintenance of the solar panels will be higher than the value of the generated power.

1000km?

[Dutch Gun]

Wow... 1000km is a pretty hefty pilot program. And here's the important phrase:

This project will supply 5 million people in France with electricity if it is successful

So... 1000km and they have no idea if it's going to be successful? It seems like the reasonable thing to do would be to pave a few km of road and see how it holds up under real conditions for a few years. But hey, money is no object when you're saving the planet, right? Well, I'm glad it's their tax dollars that are doing a giant feasibility study for the rest of us.

The Dutch have the right idea. They've started with a 100m strip to start with to see if the things actually work as intended first. I like the concept, but new products and concepts like this need to be tested pretty carefully.

For a lower price...

[cirby]

Build 1000 km of above-the-road arrays.

They wouldn't have to ruggedize the panels to let cars drive on them, they could angle them for better efficiency, and they could repair most of the things that will go wrong without having to shut down the roads.

For that matter, they could BUILD the damned thing without shutting down the roads.

Re:For a lower price...

[BarbaraHudson]

You won't be driving the space shuttle down any roads. They're now museum pieces.

Also, not all glass is created equal. Some glasses can withstand 400 psi, which is far more pressure than a semitrailer tire produces on the road, unless you inflate the tire to more than 400 psi, which you won't do if you value your life. Structural glass is coming into wider use, as the transparent floor of walkways and dance floors, and resists wear longer than acrylics. It's even been used to make bridges between two buildings that have no steel supporting members, and staircases with no steel.

Good Video Outlining Technical Challenges

[Kunedog]

There was a successful kickstarter for something similar, which IMO gets ripped to shreds in this video:
https://www.youtube.com/watch?...

If you love solar panels, then why not put them, well, anywhere else instead of on a road surface where they will be under constant, severe assault by heavy vehicles with tires that can leave light-blocking rubber on them.

Doing this would be expensive and ineffective, if not impossible. It seems good for nothing but a scam to bilk investors or as another vacuous Green PR campaign.

Re:Good Video Outlining Technical Challenges

[aXis100]

Urgh, wont maintaining solar roadways be an order of magnitude or two more expensive than bitumen?

Re:Good Video Outlining Technical Challenges

[Mr D from 63]

The one thing that is clearly missing from the article and reference pieces is an estimation of cost. There is no indication that this will be cost effective in any way. It would likely be much less costly to line roadsides and medians with normal panels.

But alas, for some, cost doesn't matter. It doesn't matter if we maximize the carbon reduction returns for our investments, it is more important to look like you are doing something extraordinary. Look at how wonderful the French are!

Re:Good Video Outlining Technical Challenges

[jonwil]

Dave Jones over at the EEVBlog has a great video as to why solar roadways are crap https://www.youtube.com/watch?...

Re:Good Video Outlining Technical Challenges

[amiga3D]

I'd like to know who in the French government is related to the people running the solar tile company.

Re:Good Video Outlining Technical Challenges

[AmiMoJo]

Jones has already been thoroughly debunked. His numbers are right but he completely misses the point of doing this. The ones he was looking at were development projects intended to demonstrate the viability of the technology, not to be financially beneficial from day one. In that light the Dutch solar cycleway has been a huge success.

Sadly this is often the case with YouTube videos. People like Jones rush to get them out and cash in, without bothering to understand what the people behind the idea are actually trying to do.

Colas is not some fly-by-night startup looking for gullible idiots to invest. It's a big, long established company that has a lot of contracts for road building and maintenance with the government, in France and the rest of Europe.

Re:Good Video Outlining Technical Challenges

[AmiMoJo]

It's a pilot scheme, intended to develop the technology. Profitability probably isn't the primary goal, developing the technology is.

You also have to consider how much the normal road surface costs, how durable it is and how easy it is to replace. Being able to simply lift a damaged section out and replace it in half an hour, instead of having to close the road overnight and resurface it, would be a huge bonus.

Note also that motorways in France are mostly privately owned and charge a toll to use them. They have not said which road will be getting this new surface, but chances are it is privately run.

Re:Good Video Outlining Technical Challenges

[Mr D from 63]

A normal road surface costs very little, it is quite durable, and quite easy to replace. Lifting sections is much more difficult than scraping and repaving long stretches. You also have to consider the supply and storage line for all those sections, and what needs to be done with damaged or aged sections that are removed.

As a surface material, it doesn't get cheaper and easier than asphalt. It is quite ignorant to think manufactured panels would be even close in comparison.

I chuckled at your private road comment.

Designed For Failure

[Anonymous Coward]

France is a leader in nuclear energies.
Launching a large scale "green energy" project that everyone knows will be a giant trainwreck and maintenance nightmare will destroy confidence in renewables and protect Areva's business for decades.

I'm being a bit of a conspiracy nutjob, but I wouldn't be surprised if it was true either.

Slashdot: News for Haters

[Idou]

Seriously, of all the things to be bitching about in the world, this project seems like it should be low on the list, yet /.ers are foaming at the mouths by the look of the top comments right now. Even if this project is destined to failure, do you actually believe humanity will never, ever be able to capture solar energy from roads? Well, if you admit it might be possible one day, then guess what? It is going to take projects like this one failing to eventually get there (or did you think technological progress hatches like a magic egg if you wait long enough?).

A project like this is NOTHING compared to the money spent on fusion so far. Is it actually any more of a long shot than fusion? Seems like people who have trouble prioritizing their bitching list should not be so critical of how others are prioritizing their long shot energy projects. Besides, this has nothing to do with the project, and you are just blowing off steam because it is Sunday, and you couldn't get a date on Saturday night, AGAIN, right?

If only people could get rich off of pissing all over someone else's idea. . . /.ers could finally move out of their parents' basements and stop being such bitter a-holes. . .

Re:Slashdot: News for Haters

[r.freeman]

> do you actually believe humanity will never, ever be able to capture solar energy from roads? Humanity also could build a carriages being polled by ants and us that instead cars. Jus it doesn't mean it's a good idea, or should be done, especially from everyone's public money.

Third time? Or more....

[Fencepost]

This is at least the third variation of this I've heard of - there's the Kickstarted solar roadways thing mentioned here, there's this one, and there was an earlier one that proposed larger drop-in units that were basically pre-fabricated road surface blocks with a clear (enough) top, internal electronics (including lighting) and connections out either off the road or possibly through adjacent units for power delivery.

The various arguments when those were initially proposed included that road surfaces and significant chunks of parking lots (the aisles, not the parking spaces themselves) are empty 90+% of the time (true), it's surfaces that are already not natural so there are no objections of "you're covering that beautiful field with solar panels," and by using pre-fabricated units you might be able to actually put in road surface at a comparable cost in labor.

I know my initial reaction at that time was that the concept wasn't terrible - it addressed real problems. The technology might not have been there, and still might not be there, but for some carefully chosen situations they might be a viable option. The biggest obstacle that I could see is that something like that would likely need some pretty tight tolerances in the installed environment, and "road bed" and tight tolerances don't always go together so well (see "alligator cracking").

Also, regarding the criticisms that it would cost far too much to cover all the roads in the USA, just how much electricity are you expecting to consume? I feel sure that on average houses with solar have less solar panel surface area than they have driveway area and a lot of them are (hoping to) produce more power than they need for their house. Covering all roads wouldn't be necessary, most likely even covering all suitable roads wouldn't be necessary.

And regarding France doing a large experiment with this, is it a 1000km stretch or is it multiple locations in differing road conditions, up to a total of 1000km of test plots?

So what if it fails

[MrKaos]

I suspect that even if there is some doubt if this project will be successful the lessons learned from doing it and operating it will provide enough operational experience so that the next effort will have fewer failures.

By doing it you learn what problems have to be overcome.

Wattway site

[luca]

This seems to be the official site of the manufacturer.

I don't know if it's just propaganda or real facts, but they seem to have taken into account all the shortcomings and engineered around them

Re:That is a REALLY BAD assessment

[Rei]

What road do you live near where the surface is packed full of rubber tire marks? Must be pretty miserable to live there, with people burning tires all the time.

A solar panel is in fact an EXACT OPPOSITE of a greenhouse - the greenhouse relies on IR alone,

Hahahaha.... oh geez... :)

Let's back all the way back to third grade and cover the topic of "photosynthesis". You see, plants need light from the sun to grow! Now class, take one of those seeds you sprouted and put it on your windowsill, and put the other in the closet... we'll bring them back to compare in two weeks. Don't forget to water!

The amount of light transmission is probably the biggest factor in greenhouse design. Here in Iceland people have to use glass (most common) or hard plastic (less common) because of the wind, thin plastic hoop houses don't survive here. Most commonly used is single pane glass. Yes, you read that right. Here in a country with "ice" in the name, it's still considered worthwhile to let the heat pour out of your greenhouse in order to get a few extra percent sunlight. Now, we have hot water for heating which reduces (but doesn't eliminate) heating costs, but still, it drives home the point: to growers, light equals growth.

Greenhouses most definitely do not rely on "IR alone".

If you're curious as to why fogged surfaces are often seen as desirable in greenhouses - it's because of shading. Fogging only causes the greenhouse to lose a couple to several percent of the light (depending on the type of plastic or glass), but it means that all of the light is no longer coming from the same angle. This helps get light to leaves that would otherwise be shaded by other leaves.

Ironically, contrarily to what you wrote, glass-covered solar panels do care about IR transmission. They don't generate power from IR, but their efficiency is correlated to their temperature, and the temperature is correlated with the radiative equilibrium of their environment.

Yes please

[Trogre]

Anything that drives up demand for solar panels should result in a ramp up in supply and a drop in price so I can get my home solar installation more quickly.

Re:Solar Roadway Bull$it

[penguinoid]

any anyway, next time France gets invaded, the tank tracks will rip them to pieces.

That's actually a bonus. "If you invade us, you have to bring your own power plants."

Why roads?

[Firethorn]

Okay, first up: I analyzed the 'Solar Freaking Roadways!!!' proposals so I know the arguments, though I think they glossed over or ignored numerous problems. My end thought was that it might be a neat system for a pedestrian walk area, where you don't have anything bigger than a golf cart traversing it.

That being said, I'm always willing to be proven wrong - it's relatively easy to get me to agree to a 100m/1km/1 Mile or so 'test strip'. 100m, for example, is long enough to get a truck completely onto the solar surface and drive for a bit - because the interface might be a destruction point. Something to study, obviously.

Okay, the reasoning for 'solar roads' is a combination of displacement and synchronicity. By displacement, we mean that the surface of a properly constructed solar panel displaces other construction material - pavement, for a road. For something like a 'solar car park', solar panels are strong enough to replace the roof, not supplement it.
- Problem: Pavement is relatively incredibly cheap and durable.
Synchronicity: By this I mean that the substitution provides additional benefits. Solar roadways, for example, boasts that you could incorporate heating elements into their units such that when it snows you can avoid the need for plowing by melting the snow off the roads, then recoup the heat used via the solar panels. Problem - I don't think they've thought about heavy snows and that you get less light in winter.
Another 'benefit' would be using LED lighting to enable 'remapping' the control lanes on a road, signaling when it's safe to pass, etc...
They even said that the solar roads would be easier to repair - have a busted hexagonal panel? Pull up with a truck that has a robot arm that automatically unbolts and lifts the damaged panel and locks a replacement in. Each panel is supposed to be cheap because it's made in an automated factory.

As such, using the panels as 'roadway shade/shelter' such that things like rain and snow don't reach the road at all, and probably even block direct sun, is a much better use.

Re:Why roads?

[Firethorn]

Roofs also need maintenance and replacing, and this is not cheap as any homeowner knows -- so the material displacement theory has to compete with that as well, though currently many rooftop solar installations do not replace shingles.

Currently ALL solar rooftop installs over structures such as houses don't replace shingles or other roofing materials. The problem is one of tightness - solar panels as direct roofing material is currently too 'leaky'. With a car port, this isn't a big deal. Hell, the panels are also structural, so they're replacing the shingles, the tar paper, plywood, AND most of the 2x4 supports. They basically only need edge support, which is easy to provide with beams.

They also tend to be semi-transparent, though that could be fixed if they were designed to replace a roof with a aluminum backing or something.

Basically, the engineering to use them over what I'd consider critical structures(IE homes) as opposed to non-critical structures(IE carport) hasn't been done or finished yet.

Re:Why roads?

[thinkwaitfast]

Anything to avoid just doing the sensible boring thing and building the cheaper solutions.

The crux of the problem

Re:Why roads?

[skids]

Well, not all, there are indeed "solar shingles", but they are pricey by comparison. Last time I looked, pricier than merited by the economics of replacing shingles.

Put the solar panels OVER the cars, not under them

[Applehu Akbar]

Kroger Markets has solar-paved one of its huge Fry's Marketplace parking lots in Phoenix (I-17 at Bell Rd). But unlike Royale's daffy scheme, they have done it the right way, by using the solar panels to shade the cars, rather than having them in the pavement. Covered parking is precious in Phoenix, and a perk generally reserved for neurosurgeons.

Re:Put the solar panels OVER the cars, not under t

[Firethorn]

If I lived in Arizona, Heck, any of the Southern states, I'd consider covered parking a perk worth perhaps paying a touch more in the store for. Plus, from a business standpoint there's a lot to be said for such an install.
1. If I phrase it as the carport structure as not being a carport, but as necessary support structure to get the solar panels safely over the cars, I can deduct and get credits for my carport as part of the solar install.
2. There's various credits and deductions with said install.
3. The power provided helps lower my max energy usage - companies are billed not only by total power used, but by maximum wattage. IE it's cheaper for me to use 100 watts continuously than 2400 watts for 1 hour a day. The daytime power from the panels will reduce the increase in power usage during business hours. Set my AC systems up to 'supercool' during that time frame to keep the temperature good once the sun comes down until my power starts dropping.
4. As you mention, car ports in heavily lit areas down south is a perk. I can attract a 'higher class' of customers that way.
5. For that matter, it saves energy in cooling costs. People burn less gasoline running the AC for their cars, especially with remote starters and such. Raised solar panels(and a few inches is sufficient) can act as a sun screen for your building, substantially dropping AC energy requirements, to the point that I remember some buildings having non-solar screens way back in the day. The energy gained from solar energy is a economic boost in such a case.

PR from a mediocre politician

[lorinc]

If you're not French and don't know Royale, you may believe this. Otherwise, you know it's just crappy PR from one of the most mediocre politician France ever had. Don't get excited by this, it's just one of her usual "big words, big failure" things.

The right tool for the job....

[charrois]

Though I applaud all efforts at green energy, I can't help but think that turning highways into solar farms is going about things the wrong way. Their purposes are fundamentally different, and as such their design is (or should be) fundamentally different. Designing a solar panel to support a considerable weight, provide as much traction in its glass surface as asphalt designed for the task, and be reasonably efficient at generating electricity has got to an engineering nightmare! Not to mention the expense of doing so. The only advantage I can see for a design such as this is that the footprint on the land isn't increased by anything more than the roads already use. But aren't there significantly more inexpensive and straightforward alternatives? Even at the very least, constructing a long array of panels along the right of way beside the roads wouldn't require more land area than already allocated to the roadways, plus the engineers would have the much easier task of designing good roads and good solar panels independently without having to work the conflicting requirements into some sort of cobbled together harmony.

Re:No, it really has not

[BarbaraHudson]

Unless you're jamming the brakes hared enough to cause a skid, you won't get a rubber coating on the tiles - it's in the air and settles out as dust. The motion of the next few vehicles will prevent dust buildup.

Otherwise, we'd never have to resurface roads - they'd be coated with a nice coating of black rubber protecting the asphalt, instead of the asphalt oxidizing and turning light grey.

Re:Heated roads are a product of mental retardatio

[Nethemas the Great]

You do realize that even in the impossible 100% efficient system, the max thermal emission cannot exceed that which was handed to it by the sun right? The difference between the black asphalt roadway and the solar powered roadway, is that for most of the year the solar energy is powering homes. Where as the asphalt is serving as a heat island all year long.