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Several sites are running a story on the solar roadway installation in the Netherlands, including phys.org and IFLScience.
However over at EEV Blog is a thorough critical review by Dave Jones which runs through the numbers and finds it doesn't add up as a practical proposal. There's references to Dave's original review of an earlier proposal, for some background on the calculations.
From the associated forum posting:
Dave shows how to go about doing ballpark engineering feasibility calculations for such a project, calculates the expected payback period, and SPOILER, shows why Solar Roadways will never be a viable technology. This time using real measured data from the Netherlands cycleway prototype, and real measured solar insolation data for the Netherlands
(Score: 2) by urza9814 on Monday November 10 2014, @06:24PM
Common sense alone says solar roadways will never make much sense. They may someday get cheap enough that we can ignore the extra cost, but even then generating on the roads is kinda moronic unless you're trying to power road lights (which is a good idea, including digital lane markings if those work out) or if you're in the middle of NYC and need to do everything imaginable to raise the density of power generation.
But in general? Yeah, this is dumb. The solar panels are more efficient sitting on your roof than they are under thick glass under a roadway. So already it's better to build the solar roads without solar panels and put the panels on rooftops. But we don't build roads out of glass for very good reasons. It's fragile and it's expensive. So stick the solar panels on the roof and build the roads out of something cheaper and easier to maintain. Like asphalt.
Of course every technology has its niche, and it's good to explore this stuff to figure out what that is, and just to keep the technology moving forward. But right now the possible use-cases for solar roadway is closer to "Tech demo at the shopping mall of tomorrow!" rather than "every roadway in America!"
There *is* one other way these could take off though, and that is if they're eventually able to replace other forms of road maintenance. If we get it cheap enough (These aren't even *close*, you'd need it to be as cheap as a regular road) then added features could tip the scales. Heated roads means no plows, no salt, no plow drivers. But that would use more power than the panels can generate, maybe we can bury some E-cat devices alongside it ;) Gotta make sure the heating is cheaper than running a plow. Could also maybe use it for emergency remote rest-stop charging stations for electric cars. Still probably cheaper to just put panels on the roof though. Maybe if the road is going through a national park. Dynamically changing lane markings could be a boon too -- for major cities like New York. They're not going to do a damn thing for Johnstown, PA. Maybe they could integrate with smart cars to extend the sensing capability, and pay off in reduced crash fatalities? That's all a long way off though; all dependent on the base technology of the glass and solar panels getting cheap enough.
This is basically the point Dave was making on EEVBlog. If people are hyping the solar roadways as an immediate solution that should be rolled out nation-wide, they're clearly full of it. That's a terrible idea. That's also why he was a lot harsher against the "Solar freakin' Roadways" video than this concept -- that one was selling a completely impossible vision , where this one is more along the lines of just running a test and seeing what happens. If you watch the video he's actually very positive about this project, very supportive of the engineers behind them, he clearly says they're doing everything right. And when you run the math, using their figures and test results, it's just not economical.
(Score: 2) by edIII on Monday November 10 2014, @08:53PM
You have some good points, it's just that when I hear the majority of the data supporting his position is derived from Norway that I'm a bit incredulous already.
There are entire countries that *aren't* Norway. For Dave to be attempting to bring the science, I think he needed to be more impartial than that, and nothing he has supports the concept of "never". I didn't read everything; He might be assuming 100% efficiency like photosynthesis directly on the roads.
That being said, when I hear solar roadways I think of the Solar Roadways [solarroadways.com] project itself.
Many of your concerns are directly answered, and your intuition is entirely correct on the numbers also making sense by gained efficiency in maintenance and the addition of other features and services.
According to them, Solar Roadways covering the US would provide three times the amount of power needed each year (based on reported consumption).
With that in mind, I find Dave's blog to be entirely suspect if it's based on peak daylight hour data from Norway, and I'm fairly positive we aren't talking about the same technology as Solar Roadways is in its R&D phase.
Unless these Solar Roadways people are just full of crap and no scientists agree with their assumptions. In that case, they are great bullshit artists. Their website has actual data and lists references contradicting Dave.
Dave has a whiteboard and a video. Not saying he might not have some points, but that he should come back when he is using data for every country and is making these assessments on a per-country basis. The data he wants is not inaccessible either, and has already been collected by other scientists.
Maybe Dave should step back and redo the analysis?
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by urza9814 on Wednesday November 12 2014, @01:31PM
Dave starts the comparison by pulling real numbers from his own rooftop solar power system. In Australia. But when you compare to the other costs of this system, it really doesn't make much difference. They could recover 10 times more energy from the solar cells, it'd still be a waste of money. The point is that the money you get back from generating the solar power is a good order of magnitude less than the money it costs to build and maintain the roadway. Furthermore, as I mentioned in my previous post, if you can put the solar cells in the roadway you can just as easily put them on nearby rooftops, where they will have a greater efficiency -- they're not under thick glass, they're not under road dirt and traffic, they're at a better angle, etc. So again, it only makes sense if you're building it somewhere remote (where it might still be cheaper than getting power there any other way) or if you're already building the roads out of glass modules with electronic systems, in which case the cost of adding a solar panel might be worthwhile.
So would a relatively small number of nuclear power plants. OF COURSE we can get enough power this way, the question is: At what cost?
Why? Dave's numbers actually confirm the plan by the solar bike path designers to power 3 homes with a 100m segment of this. In fact, his initial estimate was *better* than their actual, demonstrated test results! Again, it's not that it doesn't produce enough power, it's that the power it produces is too expensive. Is it cheaper than building nuclear plants? Is it cheaper than putting the solar panels on your roof? Hell, when you look at the concept of digging up and replacing every road in America, it *might* even be cheaper and faster to throw that money into Fusion!
Dave uses *their own data* for his calculations. And the math from there is not very complicated and does not really affect the outcome much (ie, he assumes a rather low 30% losses, but even 0% losses wouldn't make it feasible). Did you watch his video?
(Score: 2) by edIII on Thursday November 13 2014, @07:46AM
I didn't watch the video because the TFS implied that he used actual production data for his analysis. There is *no* production data for Solar Roadways anywhere in the world, much less Norway (I can't see at all how Norway's data is relevant). This is why I'm not sure we are talking about the same thing when you say "bike path" designers. Solar Roadways is not a bike path. Bike paths don't get rated for 250,000 pounds.
Now I see where you are coming from though. At first I thought Dave's objections were that it couldn't product the amount of energy required, when I knew that it could. Your objection is that Solar Roadways can't possible have ROI. That's patently false, and I don't see how Dave (or anybody) could even determine that yet either. Even the Solar Roadways people don't have numbers on maintenance savings and economic impacts of the panels other features across the board.
Solar Roadways directly addresses your other concerns. The fact is, we really *do* need to dig up and replace all the roads in America. We've spent less than half of what other developed nations have spent on infrastructure and it shows. Quite a few people have died already in bridge failures. It's inevitable. So I find it pointless to talk about the costs of digging them up when that is non-negotiable. Absolutely. Non. Negotiable. There are too many newer technologies, and asphalt doesn't cut it. America needs new interstates, bridges, and transportation technologies badly.
So if we *have* to replace the roads and bridges, we might as well get the bang for the buck. What I find amazing, but apparently true, is that if a panel costs *less* than 10k, it *beats* asphalt. We get to put them at less of a cost than asphalt.
We also get a LOT more than power generation being added to ROI. Each panel is actually extremely tough making any concerns over long term maintenance practically baseless. They beat out asphalt for strength and durability (impervious to potholes), and can keep up with the German Autobahns which have enough concrete to allow jumbo jets to land on them. Maintenance can be wholly automated with machines picking out these modular panels and putting in new ones. Since it's automated, that also implies to me less impact on traffic leading towards savings for commuters. No need for expensive machinery carted on site to cut into the ground for maintenance either. Your concern about skid marks is something they acknowledge and will wait for further testing. That being said, the rubber from car tires doesn't stick to the surface of the panel. It can be wiped off with a hand, or rain.
One cannot understate the value of good cable management and these panels (along with the installation) include abilities to run all kinds of conduit and drainage. If we do it at the same time, we *always* have a place to lay down fiber optical with it's own built in redundant power. This means micro cell towers, wifi, wimax, etc. support. No longer do you need to spend tens of thousands with ISPs to make cable runs in the street. They're modular. Pull them out, stack them to side, and put a tarp on them. This alone saves such serious amounts of money every day in the US, I'm betting that it alone takes out a significant chunk of Dave's negative ROI.
If we replace our interstates and our roads with it, I believe it's reasonable to also assume that we will realize savings with a platform that allows for cheaper design and implementation of other supporting technologies. After all, you get both power and communications at any point along the road. That's wide open for all kinds of ROI for the state in the forms of paid easements and last-mile-ISPs reselling access and bandwidth from upstream providers. At the same time we replace the roads, we are also replacing the conduit for literally all of our other communications.
All of these factors need to be included. Dave is saying that's it off by an order of magnitude, but Solar Roadways *only* needs to beat asphalt for price and overall performance too. Which they have, while also producing distributed power. These facts seem mutually exclusive. I can keep imagining all sorts of projects for traffic control and advanced services that have benefits in other areas of society making their subsidization something that makes sense.
In other words, I don't think Dave could even calculate the true ROI for it yet. I'm not going to write Solar Roadways off completely. It's a worthy enough idea to be tested at least city wide someplace in the Southwest.
(Score: 2) by urza9814 on Thursday November 13 2014, @01:50PM
Dave did a separate video on that project which reached pretty much the same conclusions. Yes, it's possible, but the ROI is going to be shit.
Some of the problems are pretty basic, and even the team developing these admits it's a problem. For example, they propose heating the panels to clear snow. The specs on their own website say the heaters draw 72W, and the panels produce 36W. In other words, these panels still require external grid power if they're going to see nation-wide deployment. Or some truly *MASSIVE* storage system (Think 2.4GW is a lot? Try storing 24 THOUSAND GWh). Same goes for powering lights and sensors at night -- read the solar roadways website, they give numerous reasons these will *require* external grid power. From...what? Coal? Gas? Nuclear?
And again, putting a solar panel under thick glass, flat on the ground, under dirt and dust and road traffic will never be more efficient than putting that same panel on a rooftop. We've gotta rebuild roofs periodically just like we rebuild roads. Design a solar shingle instead of a solar roadway, you'll get a higher ROI.
There's also the fact that they promised to have data regarding the costs of these panels posted several months ago. Site still says they "will be doing so in July, 2014." They DO actually have some test results regarding power generation, but those mean nothing if you don't have a total system cost. They got over $2 million from that Indiegogo campaign, you'd think they could take five minutes to update the website in the months since...
I mean it certainly is a cool project, and we're probably heading there someday. I just think it's more likely to be plugged into fusion plants and consuming power rather than providing power to the entire country. They've put so many sensors and indicators into it that it can't even power *itself*!