The first solar road has turned out to be a disappointing failure
sciencealert.com
sciencealert.com
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...
It was overhyped by politicians, but what isn't? Maybe they even steamrolled over engineering red flags. That doesn't mean it wasn't a valuable experiment.
The point is there shouldn't have been. Some people deduced and others hoped or willed themselves to ignorance.
The idea was terrible on paper, easily falsified by back of the napkin math. The same amount of money could have been spent on, eg, testing the commercial viability of smoothing out grid loads by making ice off peak for cooling.
Trying things helps us move forward
edit: I'm all for trying crazy moonshots. Just not down right idiotic ones that are pushed by pseudo-science and clickbait activism [1].
[1]https://www.vox.com/2014/5/14/5717036/should-we-cover-all-ou...
Isn't that saying shooting sky full of satellite for communication is stupid until SpaceX made loading anything to space 10x less expensive?
I would say the idea isn't worth trying because it clearly wasn't ready, ( I mean if napkin maths already show it is off by a factor of 10 than it really is stupid trying it ) but I don't think the idea in itself is stupid at all.
Therefore, we should fund most probable test ideas as should any scientific endeavor. The parent post claims that this particular idea was not probable to begin with (a poor idea on paper).
But that's the ideal. In the real world, political and consumer attention for projects like this most certainly is zero sum. They quickly get fatiguing and you already feel like you've done your bit.
In fact, it's probably even worse than zero sum in practice, because after being burned on junk like solar roads, you're far less likely to vouch or open your wallet for the next cool sounding tech that comes along.
It seems unlikely that well-funded scientists are _that_ stupid. It's more likely either that we're missing some reason why solar roads are more efficient at first glance, or that they have some ulterior political motive where wasting the money is intentional. Either way, laughing at them for missing things every internet commenter immediately thinks of seems like a mistake.
That said, in this case, my first thought is, "we definitely haven't run out of better places to put solar panels". The specifics don't matter much when the US has plenty of unused space to put solar farms (even just "next to the roads"). I'm pretty confused by how far the idea's gotten.
If people are still paying you for an idea that you might be somewhat sceptical about, are you going to stop doing it anyway? Maybe you will, but I imagine there are plenty of people where the money will just confirm their biases towards their work.
this is the problem when you have rich people pick and choose which ideas gets implemented. rather than having people who are actually intelligent and have experience driving innovations you have a constant flow of bad ideas. inevitable something will work and these idiots will claim that their process actually works. no, it's more like they have the money to afford a lot of failures.
Solar roads are not that kind of experiment. Even given an ideal execution solar roads would give you the combination of suboptimal roads with badly used solar panels.
Unless glas turns out to be a superior road surface (which I doubt) and unless solar panels perform better flat on the ground under a layer of dirt than raised above shadows and with a well adjusted angle (which helps the rain to clean the thing and increases efficiency) — unless all of that, putting solar panels on the side of the roads or roofa will be way more economical and ecological.
This is literally bad design: something that looks good or innovative on first glance, but is totally inpractical and maybe even destructive the longer you ponder about it.
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.
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.
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.
Solar roads do not make any sense whatsoever, as you wrote pretty much any other place is better for panels.
Perhaps you mean roads with solar panels near them that feed the passing cars energy? Now that at least sounds exciting! (Although it's probably not a great idea either, not enough battery weight saving to be worth it.)
Does it work? Apparently not, or at least: not yet. We have not successfully accomplished this, but it remains to be seen if this is a case of not yet, or never will. Experimentation yields useful data, even when the experiment is a failure.
So where were the failures? The road was less durable than expected. They didn’t account for falling leaves. They didn’t produce as much electricity as they thought it would. Thunderstorms also damaged the road.
But! It did produce a decent amount of electricity, it did successfully transmit it, and it did function as a road. Colas has given up and chose not to pursue this route anymore, but it isn’t a death sentence for the idea in its entirety. It is a failure of execution, and there will be a lot of failures before there is ever a success. I’ll end this with the caveat that there might not ever be a success, but it is too early to decide that and further experimentation might yield other interesting road construction technologies.
Your local physics department spends x10 that budget yearly, and you can't move your car on the arxiv papers it produces (if any).
P.S - Colas is not a startup https://www.colas.com/
I'm not sure how is this relevant. How this data can help engineer proper solar roadways? Where is the data on all the problems they had to solve and problems they couldn't solve?
We’ve been learning things by trial and error a lot longer than we’ve been practicing the Scientific Method. You don’t always get the data you want. You don’t always get someone to summarize the data in a nicely formatted paper published in a respected journal. You get what you get and if not quite like it, make do.
If this sort of thing, Solar Roads, doesn’t interest you, that is fine too. Maybe you even have credible reasons to be Anti-Solar Roads. It’s certainly shaky enough ground to start on, but I wouldn’t discredit this road in France as a useful experiment simply because there wasn’t a paper at the end. Thunderstorms and fallen leaves! Maybe they should have known, but they didn’t, and because they didn’t consider that, it’s exciting because now how can we go about addressing the problem if we wish to try this again? Maybe someone can build a road and let it get hit by Thunderstorms just to analyze the rate of fire, so to speak. Maybe someone can build one somewhere else to figure out how it differs from one location to another. Maybe we build a third, and start figuring if a solar road is more likely to attract strikes from a storm than other types of roads? Can we mitigate this with some kind of lightning rod? How many do we need and how spaced apart should they be? Can we capture the energy from the lightning or are they too infrequent even in the vicinity of the solar roads to be worth the bother?
A lot of those questions might already be answered or answerable without having to build all of those roads to figure it out, but at the very least, a little roadway in France can spark a lot of questions that are worth answering for anyone trying this anywhere else.
There are several factors, each alone that make this idea a non-starter. All these were known from previous experimental results so this never needed to be done. For example - 1. Placing cells flat reduces the power output by 30% over putting it at an angle and facing north. The angle varies with how far you are from the equator. So putting solar in roads will always yield at least 30% less power than putting it in an appropriate location. 2. Roads are extremely dirty. There’s dirt, brake dust, rubber, etc., not to mention shading from buildings, the natural geography and cars while they are driving over it. This will mean at least another 10-20% less power per solar cell, which will degrade as it gets dirtier. So you’re probably throwing up to 40% of your power away unless you’re cleaning them every week or so.
Then factor in damage, etc... a basic engineering assessment shows that it is infeasable, and even with massive improvements, rooftop solar and solar farms will always be correspondingly better.
But since you seem to be so big on experimentation, do you want to send me a few million dollars and we’ll put solar on the biggest area of all - the sea floor? Think of how much space there is! I mean, we can calculate that basically no light reaches it, but that’s not important, right? It’ll be valuable data!
https://gfycat.com/difficultgrizzledfox
Imagine that, but with solar over the road- you now have sheets of glass shards, live electric wiring and support steel falling down over the road. Additionally, the supports (along side the road to hold it up over the top) become targets for collision as well.
The sheer amount of materials required to make it sturdy enough to survive tornados, general high speed winds, and the occasional accident from a moving vehicle means that you're going to have a hard time coming out carbon neutral- or at the very least, you'll lose a lot of the benefits.
Of course, putting the panels under the cars is a pretty awful idea as well. Simply put, they don't belong near roads at all.
It's fascinating. Obviously they seem to grasp the system has something wrong with it, and the problem has something to do with energy. But when that line of thought begins to lead them inexorably toward the conclusion that they should actually probably stop driving immediately, like today, they take a quick left turn into something else, anything else, whatever's available and "green" - SOLAR, let's do the solar. That'll absolve our sins. Hence, where do you place the panels? In the road, where the sin occurred.
It's like the dim awareness of our actual transportation/energy predicament, is in the cellar of their subconscious, knocking at the door to enter conscious awareness, but not quite managing to get the person's attention. The mental contortions required to actually like this idea, remind me a lot of the ones required to maintain various states of denial. The fact being desperately avoided of course is that a set of changes far more sweeping and less pleasant than they're willing to admit or allow, are going to be necessary.
Could be, and I suspect that a lot of the actual engineering folks involved would agree 100% on this point. They'd probably also tell you that 5 million for real - world experimental data on the exact ways in which it failed was very much worth it.
Was there anything else worth responding to in the wordy pseudo-psychological insults?
Scientific papers are probably easier to access than anytime before.
Start by looking for optimal angels for mounting solar panels. Last I heard, unless you have movable panels the only correct angle is where they catch most of the sun in the middle of the day.
2.) Angling solar panels is a more complex problem than you might have thought: https://www.eupvsec-proceedings.com/proceedings?fulltext=mun... :)
https://www.veritasium.com/videos/2019/5/23/why-are-96000000...
https://www.sciencealert.com/here-s-what-s-really-going-on-w...
Though I'm not familiar with the specifics and details of this case (and have seen the Veritasium video describing the use), it's reasonable to assume that these treatments would be applied regardless, and the shade balls are an effective countermeasure.
The death tolls of historical urban outbreaks shows that you would MUCH rather drink the treated water.
If through your process of learning, you come up with an understanding of any situation, then you should form an opinion.
I don't mean to be rude but your question is easily answerable by reading the article I linked (and it's a short one). If you're not going to take the 30 seconds to respect my comment, I will show none to your uninformed opinion.
This NatGeo article from 2015, https://www.nationalgeographic.com/news/2015/08/150812-shade... , notes for example that they kill algae and microorganisms, and inhibit water-fowl.
I'm almost certain they'd kill lake-born fish too, preventing growth of water-borne oxygenators (which also serve as a food source, and place for eg snails to live).
Whilst the purpose appears to be to prevent plant and animal life, at least in part, it's possible a stable eco-system might still survive; but it seems highly unlikely to me -- do you have something to show me I'm wrong in my assumption?
Putting solar cells on top of (artificial) lakes not only decreases evaporation, but also cools the solar cells, making them more efficient.
It's technically easier to put things on land if possible.
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..
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.
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.
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.
There's a high probability that true beleivers still won't be convinced -- their faith transcends reason and experience. The rest of us can point to this as a Provably Bad Idea.
My only regret is that there aren't similarly conclusive demonstrations possible in all such cases.
Belief tends to become identity.
Moreover, belief becomes an ordering principle. The refutation of a belief creates the problem that there is no longer an ordering principle. This isn't always clearly obvious, but if the belief is itself part of a complex chain of interconnected beliefs, then removal of one, even if quite clearly false, creates discord within the entire structure. You've got to break down and rebuild the whole thing, which can get complicated.
(Compare, by way of technical analogue, the task of refactoring a particularly messy bit of code or kit, where it turns out that a specific feature has interactions across a wide number of other areas.)
The Kubler-Ross model of grief is, I'm increasingly convinced, actually a response to belief changes. The original research was based on patients informed of their own pending mortality, by way of fatal diagnoses or conditions, and how they responded.
Such information is a massive disruption to belief systems. And absent some mechanism for supporting transition to a different one, the classic KR response (denial, anger, depression, bargaining, acceptance) is highly probable.
The interesting question to me is what happens in cases where such responses don't develop. Where we can and do change beliefs quickly and fluidly. What do those circumstances have in common.
[1] https://unreasonablydangerousonionrings.com/2016/07/18/4-rea...
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.
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.
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:
You can still do that! Just put them on a rail off to the side, angled to get lots of sunlight.
I never understood this idea to begin with.
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.
Some ideas are just plain stupid.
It's a monumentally stupid idea. I'm surprised it isn't outright labelled as a scam. They basically cheated money out of governments and gullible people with a project that was never a good idea in the first place.
Solar is the perpetuum mobile of our time.
Engineers are paid to work things out on paper and determine whether something will work or not. Bridges, airplanes, power distribution systems, those kinds of things. They don’t use arrogance, they use math.
This isn’t particle physics - there are no “unknown unknowns” here that required a real world experiment. The economic infeasibility of solar roadways was an absolute slam dunk case.
So now we have confirmation that it was, in fact a bad idea all along. What’s the reaction? “Well, nobody could have predicted this! We had to try.” No, you didn’t have to waste all that money, you could have just listened to competent people in the first place, who all predicted this.
I mean, excuse the hyperbole, but you may as well applaud the audacity of launching Challenger in temperatures below the booster o-rings’ rated spec. Who knows? It could have worked!
Even EENblog made several videos about this in the last few weeks. Just have a look:
* https://www.eevblog.com/2019/08/07/eevblog-1233-the-demise-o...
* https://www.eevblog.com/2019/08/07/eevblog-1234-more-epic-so...
* https://www.eevblog.com/2019/08/18/eevblog-1236-german-solar...
This was 100% predictable.
Pavegen pivoted to collecting info about people walking on their sidewalks, rather than energy.
Wow. Switching from saving the world, to spying on everybody in it. That's almost a perfect microcosm of how the tech industry seems to have morphed in the last decade.
- innovation
- productization
- marketing
- milking IP
As a straight-up marketing device -- say, a way of creating some interactivity at your storefront in order to get people to linger there longer -- then I guess it's fine, or at least no worse than any number of other things. I actually find that less objectionable than painting it with a green "we're helping to save the world" veneer that is either very cynical or very deluded. It takes a trivial amount of cognitive effort to understand that energy recovered from footfall will never, ever, pay back the embodied energy to produce and install the device. (Even moreso if you include the metabolic efficiency of human power in the energy calculations). This shouldn't be hard to figure out: it was pretty well understood by the end of the neolithic. But I suppose people are capable of remarkable feats of mental gymnastics.
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.
Many of the projects that have not seen the light of day are in that state because they were dumb, not because nobody thought of them before.
They have to be:
1) cleaned often
2) have very little traffic
3) have a very large surface
And one of the solutions that pops up is: airport runways! They have a huge area, way larger than necessary to land a plane. The surface is always kept in good condition. The traffic is minimal, except for a few very busy airports. Some airports handle just a few planes a day, the rest of the time they stay unused, when they could've been producing energy instead.
All airports have more than enough free space as it is, which can be used to set up solar panels in the most optimal way.
It's a road. It normally doesn't generate energy anyway.
Anything here is a plus, especially when it comes to research.
They just have to take what they've learned from this and apply it to the next attempt.
And from the sounds of it, the only thing they have to really focus on is ensure the next one lasts long enough to pay for its own construction.
Solar sidewalks might be a better idea.
I’ve always wondered if there were some way to use the space above (as in you drive under them) the roads instead. Is there a mass-efficient-enough design to make putting panels above the road a profitable thing.
Can we just applaud that people are trying something new?
Or are we going to shoot it down because of pessimism?
If you know so well what works, then do your best and make it happen or write a guide on how to do experiments that almost always lead to success.
They didn’t fail fast, but they failed with relatively little costs. What is 5 million to the national GDP of France?
It seems to me they were trying something new, were brave and paid the price. In most cases you get nothing back.
HN of course is full of people who are experts on every topic, so naturally there was no need to actually perform this experiment. They could have just accurately predicted its faults and performance from theorizing alone after reading just a few articles about materials science and the properties of modern roads.
While we're busy talking about the obvious and predictable failure of this experiment, we should also take a moment to also revisit the obvious and predictable failure that was Dropbox: https://news.ycombinator.com/item?id=6625306
Nothing was learned.
It’s loose change compared to the money spent on fusion research. And even after being a failure, it still generated more power.
It's also worth considering that we may choose to move away from big, expensive, fossil-based roadways to more compact, inexpensive and 'smart road' options.
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.
I mean, the road will get car-exhaust-sediment on it, like any other road; and all sorts of mechanical trauma. Roads wear down, after all, one way or another. Why have panels on the roads? Is there no land available in France?
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?
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
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.
A road is only the 2nd worst place to put solar panels after a cave.
Why not just build a solar ceilling?
Maybe solar tracking panels above parking lots would be better, and there's zillions of Walmarts with enormous parking areas the size of some airports that could co-locate solar farms.
“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.
But, we should all be paying “carbon taxes” so that these same idiots can save the world.
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.