
The first solar road has turned out to be a disappointing failure - prostoalex
https://www.sciencealert.com/the-world-s-first-solar-road-has-turned-out-to-be-a-disappointing-failure
======
Smithalicious
I never managed to see the advantages of having a solar road compared to just
having a normal road with solar panels next to it. Or above it. Or literally
anywhere else. In fact I can't think of many areas that still get direct
sunlight that would make for a worse place to put solar panels than on the
road...

~~~
belorn
The advantage that people wanted to get is that in the end you also get a
road.

Roads take up space, cost money to build and maintain. If you build it next to
the road the road need twice the amount of space and still require the space,
construction and material for the actually road. If you build it above the
road you get all the issue of overhead roof on a road (trees that fall on it,
wind, height limitation).

In addition to saving money by not actually building a normal road, the idea
in most of solar roads projects is that it combines the work of putting
internet and power cables into the ground.

That it currently do not work economically is the issue that the article
showcase. Maybe it will never work and it always will be cheaper to simply
build the road with current construction methods, put internet/power cables
under it, buy large lands (farming land?) and construct regular solar parks.

Other concept of combining solar panels and building materials that is argued
as more cost effective are roofs on houses. Same concept as solar road, ie
that you get a roof and a solar panel in one without spending the work and
material for both, but I have no idea if the economics is better than solar
parks or if it is cheaper to just build normal roofs and go the route of
getting land and building solar parks separately.

~~~
mbrumlow
> That it currently do not work economically is the issue that the article
> showcase.

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.

~~~
Wowfunhappy
I do wonder if the concept could work on a sidewalk, given that they aren't
being perpetually driven over by 3,000+ pound vehicles.

~~~
ars
The ground pressure from a truck is around 150 PSI. A woman wearing high heels
can match, and even exceed that.

So the sidewalk would need to be just as strong as the road.

~~~
kbutler
Common physics example, but it disregards how women actually walk and stand in
heels. They walk on their forefoot, rather than balancing their weight on the
heel.

[https://www.semanticscholar.org/paper/The-higher-the-heel-
th...](https://www.semanticscholar.org/paper/The-higher-the-heel-the-higher-
the-in-ten-healthy-Speksnijder-
Munckhof/9547d261aea7401caad230ecca180363ff13f0b4/figure/1)

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.

~~~
reitzensteinm
Yeah, and a heel surface area of 32.3 +/\- 4.4 cm^2. There are shoes with heel
surface area of sub 1cm^2.

I don't think the study invalidates parents claim, if anything it more it less
supports it.

------
caymanjim
This was not at all a failure. They built a 1km experimental road. They gained
valuable information about real-world performance and technical challenges.
It's not as though they built a 100km long six-lane highway with unproven
technology. They built a tiny one-lane trial to test a promising idea.

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.

~~~
reitzensteinm
The trouble with this viewpoint is that there are an endless number of things
we _could_ be trying, and it's more or less a zero sum game.

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.

~~~
craz8
It’s _never_ a zero sum game - we can try many things at once, some will work
well, some will work poorly, some won’t work at all

Trying things helps us move forward

~~~
__sy__
And some aren't even worth trying in the first place. Like this idea.

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...](https://www.vox.com/2014/5/14/5717036/should-we-cover-all-our-roads-
with-solar-panels)

~~~
ksec
Excuse my ignorance, isn't this a technical challenge, rather than the idea in
itself was stupid?

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.

~~~
arcticbull
The thing about solar roads is they're covered by cars, and they don't work
when covered, for obvious reasons. Then all the road dirt, grime, tire dust,
oil, etc, builds up on top of them blocking the light for good. The road is
about the worst thing you can possibly try and generate solar electricity
from.

~~~
ksec
Thx. Valid Point.

------
WalterBright
"The engineers also didn't take into account the effects of leaves, which
caused damage and limited the amount of electricity the panels could produce.
They also didn't think about the pressure and weight from tractors, two locals
told Le Monde."

They were warned about this.

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

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

Spending the money to solve problems on your first run is likely to not
actually solve all of them.

Then again, this could be a bold exercise in fraud and/or incompetence.

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

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

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

~~~
fencepost
As a proof of concept trial it wasn't very expensive. Unrelated, but just for
comparison it cost about a much as Uber lost every 2.5 _hours_ in 2019Q2.

They built a Minimum Viable Product for a trial and found out that it wasn't
actually viable and didn't provide the hoped for value. They probably also
learned a lot with real world experience (that they wouldn't have been sure to
have in a staged setup) and may come back with something different in the
future.

Personally I'd be curious about the math on how much these panels pick up,
whether some kind of contactless power transmission would be viable at highway
speeds, and whether in 15-20 years we'll see interstates paved with these
providing trickle power to fully automated electric trucks running as "road
trains" across the country.

~~~
fyfy18
Have there been any trials on creating a solar roof over highways? It seems
like a much better option as the panels don't need to be reinforced, and they
can be angled towards the sun to aid cleaning. We already know how to build
stable metal framed structures (and panels aren't that heavy). In somewhere
like Spain it would reduce the requirement for AC while driving, making it
even more green. During rain it would increase visibility and reduce water on
the road, making the road safer.

~~~
fencepost
If you're building new structures I'm positive that the economics work out
better for simply doing separate solar farms. Building them above a road has
no major advantages and potentially both increases construction costs and
increases the chances of unfortunate interaction (eg an accident taking out
panels).

The sweet spot for solar roads would be in places where the generation benefit
outweighed the extra cost when a road was being redone anyway - and even then
only if the materials were up to the task.

------
dghughes
Most solar panels are very inefficient at converting the sun to electricity so
they need all the help they can get. Two things solar panels require is to be
clean and to be perpendicular to the sun. A solar road achieves neither of
those things.

~~~
edoceo
Panels at the side of the roads?

~~~
agumonkey
panels above urban tunnels, maybe powering some air filtering system ?

~~~
dredmorbius
Aqueducts have been suggested as siting locations.

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.

~~~
agumonkey
Never thougt of them. Great indeed.

------
buboard
Help me understand the logic behind taking a PV and stepping on it in the
worst possible way, leaving dirt , rubber etc, when every PV that is exposed
only to the open air needs regular cleaning / maintainance. And its being
frequently under the shade of cars

~~~
doteka
I'm curious how you arrived at that conclusion? Common wisdom, at least a few
years ago, was "cleaning isn't worth it".

([https://phys.org/news/2013-07-solar-panels-
worth.html](https://phys.org/news/2013-07-solar-panels-worth.html))

~~~
jdietrich
Self-cleaning glass is a fairly mature technology and will work effectively on
a rooftop solar installation. That won't work on a solar roadway, which a)
needs a textured surface to provide adequate grip for vehicles and b) can't
retain any sort of coating due to friction and c) is constantly being covered
in axle grease, tire rubber, brake dust and the innards of various wild
animals.

[https://en.wikipedia.org/wiki/Self-
cleaning_glass](https://en.wikipedia.org/wiki/Self-cleaning_glass)

------
jwr
For some reason, solar roads are a very aggressive meme (in the classical
sense of the word). They capture the imagination and blind people to
engineering reality.

Solar roads do not make any sense whatsoever, as you wrote pretty much any
other place is better for panels.

~~~
SllX
They capture the imagination because there are plenty of places you _don’t_
want to build solar panels. Namely places that you want to leave alone for
ecological or recreational purposes. If you can take a piece of infrastructure
that is pervasive throughout a built environment and give it additional
purpose, then you can save on or reduce the land you specify for this purpose.

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

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

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

~~~
zzzcpan
It's not an experiment that can yield anything or teach us anything if there
is no paper and no data. A fraudulent startup maybe.

~~~
SllX
How big is your laboratory? Is it a space you rent out, or is it all the known
Universe and all of its history?

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.

~~~
stephen_g
It’s simply a waste of money if we can do the maths and see that it’s always
going to be vastly worse than putting them on roofs, on gantries over roads,
or literally almost anywhere else but on a dirty, flat surface with huge
pressures on what we already knew were fragile and durable cells.

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!

~~~
stephen_g
(Note that when I say panels need to face north, that’s because I am in the
southern hemisphere. Obviously in the northern hemisphere it’s the opposite so
should face south).

------
rdiddly
This was obviously never going to work; I think it's far more interesting as a
piece of morality theater and/or a psychological ink-blot test. Because who
looks at a system like this (individual humans carted around extravagantly in
an energy-intensive, 4,000-pound CO2-belching murder machine, on an expensive
and space-intensive road created _just for them_ ) and thinks, you know what's
wrong with this system? _It doesn 't generate enough energy._ Mmm yeah, you're
almost right. Sort of like how a violent person doesn't generate enough not-
punching-people. Keep going with that reasoning. See if you can use the phrase
"in the first place" in your answer.

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.

~~~
fencepost
_This was obviously never going to work_

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?

~~~
Atheros
May I please read the real-world experimental data that will save other
companies millions of dollars?

~~~
eitland
Go right ahead.

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.

~~~
lorenzhs
1.) I think the OP was asking where they can find the insights obtained from
this failed solar road test that would allow others to save money. Not general
photovoltaics stuff.

2.) Angling solar panels is a more complex problem than you might have
thought: [https://www.eupvsec-
proceedings.com/proceedings?fulltext=mun...](https://www.eupvsec-
proceedings.com/proceedings?fulltext=munzke&paper=33024) :)

------
doteka
I remember at the time this was announced, I was working at a startup in the
solar PV industry. Our collective response on the workfloor was, "wow, that's
an incredibly stupid idea for so many reasons". Surprised it took them so long
to admit failure.

~~~
Mirioron
If they had admitted failure earlier, then they couldn't milk as much money
from suckers.

------
debatem1
Seems like you'd be much better off floating them on a lake. There was a
project a few years ago to do this both for power and to reduce evaporative
loss in reservoirs, but I don't know if anything has come of it.

~~~
pbhjpbhj
Wouldn't you kill the lake, unless you only covered a small proportion of it.

~~~
pacala
Depends on the lake. There is a reservoir near LA covered in millions of black
balls. Apparently this is a side effect of water quality regulation, direct
sunlight triggers a chemical reaction that produces harmful byproducts. As a
bonus, evaporation is also reduced, which matters in semi-arid climates like
Southern California.

[https://www.veritasium.com/videos/2019/5/23/why-
are-96000000...](https://www.veritasium.com/videos/2019/5/23/why-
are-96000000-black-balls-on-this-reservoir)

~~~
pbhjpbhj
I saw that story surface again recently, it's a perennial pleaser. Those balls
are used to cover lakes of processed water which is eventually used as
drinking water; that's not a living lake.

This NatGeo article from 2015,
[https://www.nationalgeographic.com/news/2015/08/150812-shade...](https://www.nationalgeographic.com/news/2015/08/150812-shade-
balls-los-angeles-California-drought-water-environment/) , 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?

~~~
pacala
While I'm not an expert, I suspect you're right. Point being that some lakes
serve a different purpose than supporting a thriving ecosystem.

------
_Nat_
Solar roads seem like a really cool technology. Like, if they worked great and
were affordable and everything, then awesome!

But, practically speaking, they seem to violate the [single responsibility
principle]([https://en.wikipedia.org/wiki/Single_responsibility_principl...](https://en.wikipedia.org/wiki/Single_responsibility_principle)).
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.

~~~
kolinko
You know you kind of described how trains work? :)

I just did a quick calculation for Poland - we have 11k km electrified train
tracks, with ~1.5m of space between the rails. If I calculated correctly,
putting solar panels there would give us ~8-15tWh energy per year, which is
5-10% of the required electricity production for the nation.

I've never been a fan of the idea of solar roads, but solar railways might
actually make sense...

~~~
reaperducer
I don't know how they do it in Poland, but in some countries when you flush a
toilet on a passenger train going above a certain speed, the nasty stuff just
evacuates to the space between the tracks.

~~~
_Nat_
Seems like any sort of solar panel on the ground is going to be prone to get
nasty stuff on it.

I guess they might just have them at an angle, then trust the rain provide
some light cleaning, while a street/rail-cleaner could go by for more thorough
cleanings periodically?

I mean, I dunno what exactly their strategy is, but I'm assuming that they're
not counting on a road to not get dirty. Cars leave rubber from their tires,
drip oil, drop trash, etc..

------
hmd_imputer
Solar Freaking Roadways! Do you guys remember this viral youtube viral video?
[https://www.youtube.com/watch?v=qlTA3rnpgzU](https://www.youtube.com/watch?v=qlTA3rnpgzU)

~~~
celeritascelery
When I first saw that video I thought, “this has to be a joke right? They
can’t actually think that is feasible.” And here we are…

~~~
hmd_imputer
The video attracted so much undeserved attention that many engineers felt that
they had to produce a corresponding debunk video explaining why it is such a
useless idea and why asphalt is currently our best option on building roads.

------
Endy
You know, I always wondered why they didn't go for solar covered sidewalks,
which would provide shade to pedestrians and power to everything that needs
it. Roads seem like a better place for pressure-based generation (of anything,
frankly).

Still, just for the enthusiasm they garnered and the continued push toward
making renewable energy generation interact with the everyday, the idealists
should be commended. The engineers... not as such, no.

But, silly question, knowing very little about this field, couldn't it be
possible to (co)generate power from the heat and pressure that roads endure on
a near-constant basis?

~~~
nullwasamistake
Solar roads and sidewalks are a PR stunt. Abrasion is no joke, nothing
optically transparent survives on the ground. You can see this easily in the
cellar "pavement lights" common in NYC and other old cities. Light still
passes through after a century, but maybe 20% and very diffuse. Bad for solar
panels.

Roads don't absorb enough energy to generate power, they're not flexible
enough. They're designed to not absorb energy since it hastens breakdown.
Potholes are a good example of a road surface energy absorber :) .

Solar roofs are a far better bet. Elon is onto something there, but time will
tell if costs can be brought down enough. Besides the good PR, solar roofs
substantially reduce heat absorbtion, important in the sunny climates solar
works well in. And we have a ton of wasted roof space. Many companies would
willingly allow roof panels to be put up for free if the economics for power
generation were good enough.

~~~
pbhjpbhj
I think you misunderstood the parent, they said "solar covered sidewalks" that
shade pedestrians, so roofs.

Solar roofs on car parks seem good to me; better than using pasture land
converted to solar farms which I'm seeing more and more in UK.

~~~
nullwasamistake
Somewhat. OP also mentions generating energy from the pavement, which I don't
think will ever be reasonable.

Solar car park covers are a great idea. Easier access than roofs, don't need
to be water proof. Good cooling airflow underneath. Tend to be close to cities
where power is easier to transport.

Solar parking lot covers are the best ROI solar installations I can imagine.

Surprised Telsa isn't doing this with their SuperCharger stations

------
higherkinded
Who would've guessed? Getting a kilometer of solar panels installed as a road
(sic!) in a region that has a cloudy skies most of the time. It's borderline
genius. How did it get any approval at all? Who treated solar panels being
used as a road (probably to spend some more tax money on casing?) as a good
idea? How is it not just obvious that it will not even get close to the easier
and cheaper (rooftop panels) options? This imitation of environment care is so
hilarious that I don't have the proper words to describe it.

------
nullwasamistake
This was a PR stunt from the beginning.

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.

------
dredmorbius
There is one and only one bright spot I can see in this test: the concept was
trialed under ideal conditions according to its proponents, and failed
spectacularly.

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.

~~~
RyJones
[http://www.whenprophecyfails.info/Conditions.htm](http://www.whenprophecyfails.info/Conditions.htm)

~~~
dredmorbius
Interesting, though I think there's more to it than just this.

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.

------
m3at
If you can cope with the swearing, this is an interesting debunking of an
other (US) solar road project with preposterous claims: [1]

[1]
[https://unreasonablydangerousonionrings.com/2016/07/18/4-rea...](https://unreasonablydangerousonionrings.com/2016/07/18/4-reasons-
solar-roadways-are-fucking-stupid/)

------
crocal
As a side note, falling leaves is one of the most dreaded problem in rail
transportation. Not only does it obstruct things very efficiently, including
the passage of light, but it also makes the rail surface very slippery, making
it sometimes impossible for trains to actually brake using mechanical means.
Much much worse than snow or rain. One sympathizes.

------
userbinator
_French officials said the road, made of photovoltaic panels, would generate
electricity to power streetlights in Tourouvre, a local town._

I don't know how reliable they are, but solar-powered streetlights are already
common in some areas --- and being mounted high above on the lights
themselves, the panels are far less likely to be damaged.

~~~
Mountain_Skies
Wonder if that would also help reduce light pollution if the panel was wide
enough compared to the lens over the light.

------
remote_phone
It was a failure but I’m glad they tried it. Hopefully something like this
comes to fruition and we learn more and more with every iteration. Solar roads
are a great idea. Maybe it means it needs daily sweeping with electric vacuum
trucks or something but if it’s producing enough electricity then it’s worth
it.

~~~
nordsieck
> It was a failure but I’m glad they tried it. ... Solar roads are a great
> idea.

It was a bad idea. Even in theory. The only positive thing about it is that it
captured the imagination of lots of people who know nothing about solar or
roads.

~~~
Mountain_Skies
The frustrating thing was that pretty every problem that arose during these
trials were already known. Those who spoke up were ridiculed for being
naysayers. There's a balance between those who reflexively oppose everything
and those who have an informed opinion based on experience and knowledge.
There was quite a bit of overlap between those who strongly supported solar
roadways and the "I f __*ing love science! " crowd that have turned science
into something indistinguishable from magic.

The original installation in Idaho ran into predictable problems almost
immediately. The much larger installations had very little justification for
going forward other than it was very popular with a rather vocal group of
voters. Doubt any of the politicians, celebrities, or their fans who pushed
this and dumped all over those with credible objections will apologize for
their part in the boondoggle.

------
ben509
> The French minister for energy said she wanted to have solar panels on one
> mile of road every 621 miles in the country within the next five years.

You can still do that! Just put them on a rail off to the side, angled to get
lots of sunlight.

------
cryptoz
Why wasn't that strip of land right by the road converted into a solar strip
instead? It looks like that shoulder has almost as much physical area to it
and would take a lot less wear and tear.

I never understood this idea to begin with.

~~~
close04
I think the idea was to take advantage of land that cannot be used otherwise.

~~~
Mountain_Skies
Most roads are in rural areas with plenty of room next to them. The inventors
were very aware of this, being from Sandpoint, Idaho.

------
inflatableDodo
As was foretold. This is all very, very simple.

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.

------
aniijbod
Does anyone but me have the suspicion that the animosity towards solar roads
was something to do with a 'nerve being touched', some kind of 'triggering'?
Sure, they might not work out, but lots of stupid-sounding ideas ('a horseless
carriage? Whatever next?') have turned out to work, just as much as lots of
somewhat futuristic but nonetheless sensible sounding ideas have turned out
not to be here yet ('flying cars are just around the corner'). Who knows, at
some point in the future, with different technologies and materials, different
efficiencies and performance, we might indeed find solar energy being
collected from roads. Just as we are laughing right now at the current,
ludicrously oversold and patently unsuccessful efforts, future generations may
be laughing at our arrogant dismissal of an idea that might ultimately have
just turned out to have been ahead of its time. Let's applaud the audacity of
the solar roadways hubris in the spirit of uninhibited innovative endeavour,
just as much as we pat ourselves on the back for having successfully spotted
its obvious shortcomings and predicted its seemingly inevitable struggle for
survival.

~~~
teawrecks
Yeah I don't know why the article is so negative. Any engineer would look at
this and say, "cool, a few more problems to solve" not "well golly, I guess
there's nothing we can do about a few leaves".

~~~
red75prime
Like placing the panels above roads, for example. It helps to get optimal
inclination of panels too, and reduce stress levels, and eliminates losses
from cars' shadows, and simplifies maintenance, and reduces pavement costs.

Some ideas are just plain stupid.

------
gbraad
It is the dumbest idea to use a solar road when there are roofs; like bus
shelters. train stations or even sound walls that can be converted. Cars would
literally rip these roads apart due to dirt and grind.

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-1233-the-demise-of-solar-roadways/)

* [https://www.eevblog.com/2019/08/07/eevblog-1234-more-epic-so...](https://www.eevblog.com/2019/08/07/eevblog-1234-more-epic-solar-roadways-fail/)

* [https://www.eevblog.com/2019/08/18/eevblog-1236-german-solar...](https://www.eevblog.com/2019/08/18/eevblog-1236-german-solar-freakin-roadways/)

------
mmmBacon
There was a fairly ridiculous promotional video going around YouTube circa
2014 about a couple who “invented” solar roadways. I’ve placed a link here for
your amusement.

[https://youtu.be/qlTA3rnpgzU](https://youtu.be/qlTA3rnpgzU)

------
nkoren
Yes, solar roads were always the answer to the question of "where is the
absolute worst possible place to put solar panels".

This was 100% predictable.

~~~
Animats
Could be worse.[1] Remember the schemes for recovering energy from traffic on
sidewalks and roads?

Pavegen pivoted to collecting info about people walking on their sidewalks,
rather than energy.

[1] [https://pavegen.com/](https://pavegen.com/)

~~~
pasabagi
>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.

~~~
jacquesm
The four stages of technology:

\- innovation

\- productization

\- marketing

\- milking IP

------
Causality1
Anyone who bothered doing the math knew this was a horrible idea from the very
start.

[https://m.youtube.com/watch?v=obS6TUVSZds](https://m.youtube.com/watch?v=obS6TUVSZds)

~~~
brian-armstrong
For those who don't watch him, EEVBlog has had excellent videos on the
feasibility of solar roadways.

~~~
zzzcpan
To summarize his videos: solar roadways were never feasible even in theory
with quick back-of-the-envelope calculations and all of the known solar
roadways projects in the world have failed or are nearing failure.

------
phtrivier
I can't imagine how hard it must have been, in France of all places, to try
something that bold and risky and obvious to oppose beforehand.

We're the country of ruthless self deprecation coupled with perfectionist
universalism.

I hope something was learnt here (other than learning not to do it again), and
I'm absolutely confident the people who cluelessly pushed for it will go on
their public careers unaffected while the innocents are punished.

We've done more insane stuff and survived to tell the tale.

But really, PV in Normandy ? Come oooooon....

~~~
jdietrich
_> I hope something was learnt here (other than learning not to do it again)_

I'm afraid not - the trials played out exactly as the naysayers predicted.
Most of the panels cracked under load and failed due to water ingress; those
that didn't became woefully inefficient due to soiling. They were dangerously
slippery even in ideal conditions, they cost much more than a conventional
rooftop installation and they never generated as much electricity as a rooftop
installation even when they were brand new.

The whole exercise was a complete waste of time and money.

------
meerita
I think the best for societies is solar roofs. Much better surface
availability. Solar roads, filled with thousands of cars cannot suck energy
from sun so well as houses' roofs.

------
lucid00
I'm not sure I'd put "doesn't generate enough energy" in the failure category.

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.

------
jacquesm
If anybody is disappointed here then they have only themselves to blame. This
was dead obvious to anybody with half a working brain and a basic idea of the
concepts of road construction, photo-voltaics and general power
infrastructure. Doomed to fail and should not have passed the first phase of
review for feasibility.

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.

------
Grue3
Made me think, what roads would actually be suitable for this?

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.

~~~
absk
Why does it have to be roads?

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.

~~~
tom_mellior
I'm not an expert, but I expect that a lot of that seemingly free space to the
sides of runways is kept deliberately clear in case of emergency landings and
whatnot. Cluttering it with solar panels would probably be a no-go; imagine a
plane crash-landing into the middle of a huge electrical installation not
easily accessible for firefighters.

------
torpfactory
The only thing roads have going for them as a location for solar is that we
(humans) have a lot of road area to work with. Wouldn’t it be great if roads
did double duty supporting our tires AND making some energy?

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.

------
mettamage
Hmm...

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.

~~~
thaumaturgy
Yeah, this is how I see it too. It was an experiment. It failed. Things were
learned from deploying it into a real-world environment. This may contribute
in some way to a future technology, as often happens.

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](https://news.ycombinator.com/item?id=6625306)

~~~
roar-of-time
The comments on that page are overwhelmingly friendly. And regardless, how can
you even compare the two?! Dropbox fulfilled an obvious need and fulfilled it
very well, whereas "solar roads" don't seem to be a solution to any problem at
all!

------
8bitsrule
Solar roads seem like a very expensive and thus fixed alternative, when we
have a big enough expense ahead of us moving HVAC, transportation,
manufacturing, etc. to green sources. Keeping solar generation separate is
more flexible.

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.

------
TaylorAlexander
This article from 4 days ago says a solar road in the Netherlands is doing
well, so it seems like the French road is just a bad design? I don’t know if
they are in fact different hardware:

[https://www.businessinsider.com/worlds-first-solar-road-
turn...](https://www.businessinsider.com/worlds-first-solar-road-turned-out-
colossal-failure-2019-8)

~~~
close04
The one in the Netherlands seems to be a 70m solar cycle lane. Cars will
destroy a surface a lot faster than bikes. Maybe (dedicated) bike lanes would
be a good place to start with this.

~~~
tzs
It's not obvious to me that cars will destroy a surface faster than bikes.
Yes, cars weigh a lot more, but that weight is distributed over a larger area.
The force on a given square millimeter of the surface that the vehicle is on
is actually 2-4 times as high for a bike than from a car. This is why bike
tires typically are inflated to 2-4 times the pressure of car tires.

~~~
WalterBright
It's not the point load, it's the total load. Which bends the road. Bending
brittle things like solar cells cracks them. Movement of the car also causes
compression waves to move through the roadbed.

Roads need regular resurfacing because bending the roads constantly causes
them to crack and crumble.

~~~
close04
Also wider tires on cars are able to catch and drag small pebbles that add to
the damage.

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

------
PeterStuer
Outcome perfectly predicted at the time. And no, you do not need to eat a dog
feces sandwich to know it tastes bad.

------
baud147258
One could question (like the article did) the wisdom of building a PV project
in Normandy, which has to be one of the rainiest and most cloud-covered area
in France, unlike somewhere in the Southern half of the country, where the
climate get a lot more sun year-round

------
einpoklum
It was "unprecedented" in 2016 mostly because it was kind of a sketchy idea.

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?

------
mynameishere
_They also didn 't think about the pressure and weight from tractors_

I mean, the hell? I wouldn't put solar panels in a playground, because I would
assume 50 pound children running around would destroy them. Obviously, motor
vehicles will. And very quickly.

Is this some sort of insane joke?

------
api
Why would this even be tried? It's an obviously terrible idea for lots of
reasons.

------
blunte
Fortunately we didn't give up on flight after the early airplanes.

Maybe expectations need to be adjusted, but experiments like this are worth
doing! We don't know exactly what they will lead to, but they often add to
progress.

~~~
magicalhippo
> Maybe expectations need to be adjusted, but experiments like this are worth
> doing!

No they are not. Solar roads do not make sense, not for a looooong time
anyway.

So far, all of the currently failed solar road projects have failed in utterly
predictable ways[1][2][3], and I'm certain nothing novel has been learned.

There are so many better places to put solar panels than beneath roads. If
anything they should put water pipes to utilize the heat. But solar panels,
that's like trying to optimize a function for another 0.03% speed while
there's still order of magnitudes of trivial improvements laying on the table
elsewhere.

[1]:
[https://www.youtube.com/watch?v=dM50P4K9UVk](https://www.youtube.com/watch?v=dM50P4K9UVk)

[2]:
[https://www.youtube.com/watch?v=7ngWjH0jdRo](https://www.youtube.com/watch?v=7ngWjH0jdRo)

[3]:
[https://www.youtube.com/watch?v=7ngWjH0jdRo](https://www.youtube.com/watch?v=7ngWjH0jdRo)

~~~
WalterBright
> they should put water pipes to utilize the heat

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.

~~~
blunte
I know there have been some applications of piezoelectric floors put in places
people walk (to generate small amounts of electricity). I wonder if this could
have some practical value in roads. The energy would be small, but perhaps it
would be enough to keep some distant electronic systems fed.

~~~
thombat
The problem with piezoelectric flooring is that the power generated is
"stolen" from the person crossing it. Take too much power, e.g. by having a
perceptible deformation of the surface, and the person will have the feeling
of walking on soft sand or snow and may avoid walking on it. Take too little
and the exercise becomes pointless: even with a very generous set of
assumptions the PaveGen system produced 1/5000th of a person's power need.

[1]
[https://www.theregister.co.uk/2015/05/26/pavegen_the_company...](https://www.theregister.co.uk/2015/05/26/pavegen_the_company_that_cant_make_energy_out_of_crowds_tries_to_make_money_out_of_them/)

------
mavhc
Pretty sure the only people who wanted solar roads were people who wanted
roads and wanted to avoid protests from environmentalists.

A road is only the 2nd worst place to put solar panels after a cave.

------
atoav
Solar roads are a prototypical example of an idea that looks/sounds cool to
regular people, but is in fact totally useless.

Why not just build a solar ceilling?

------
duxup
Solar panels and roads have different properties for all sorts of good
reasons. Why people want to compromise both is beyond me.

------
WheelsAtLarge
Why aren't sidewalks being turned in to solar sidewalks? I wondered how robust
solar roads could be given that even concrete roads fall apart when you have
thousands of cars driving on them. But solar sidewalks, that could work.

~~~
kirrent
It's been done with bike paths. Also got a terrible track record with a lot of
failures.

------
cryptozeus
Lets test in production!

------
freediver
Lets not forget that the first electric car was also a disappointing failure.

~~~
egdod
The first X was a failure for many good ideas X. But that does not mean that
every (or even most) failures are _just bugs being worked out of good ideas_.
Sometimes a failure is just a bad idea.

~~~
freediver
That was entirely my point.

~~~
egdod
Was it? It seemed like the opposite of your point.

------
ijiiijji1
Thunderf00t says _Solar frickin ' failure._

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.

------
trilila
“Cracks have appeared, and in 2018, part of the road had to be demolished due
to damage from wear and tear.” as opposed to regular roads which never crack

“the road was only producing half of the expected energy” - great, so just 2
km of a solar road could power the streetlights of an entire city the size of
Tourouvre, 3700 people.

We shouldn’t raise the white flag so quickly. I think we need a second
iteration at least before we call it a failure.

~~~
GhostVII
Cracks don't cause a regular road to fail entirely, while if a solar panel
cracks in half, it will most likely stop working.

Also I don't see how solar roads make any sense when there is so much unused
roof space and parking lots. Putting panels over a parking lot is much easier
since you don't have to build them to withstand many-tonne automobiles, they
will always be in full sunlight instead of being covered by dirt and vehicles,
and they can be angled towards the sun. Even in theory, I think solar roads
are a failure.

~~~
trilila
So after my erroneous comment, i have learned that roofs, parking lots and
bike lanes are better candidates. I just dint want to give up on converting
asphalt to energy generators.

~~~
Mountain_Skies
Think the person you responded to meant for the solar panels to be above the
parking lot, not the parking lot surface. IIRC, Google has quite a far solar
panels in their parking lots, where they not only generate electricity but
also provide shade for the cars parked there. I've also seen a couple of
rather massive solar panels in central Atlanta near CNN. I was told they were
installed by Ted Turner because he has a penthouse nearby. No idea how much
power they generate but it does provide some nice shade.

~~~
trilila
There was a different comment recommending parking lots, and i summed up all
my thoughts in the comment above. To me it sounds like France could use some
shade as well as some clean energy. Calling it quits is just not an option
given the crazy heat waves of recent in Europe, and we should hold onto to
anything that improves what we have right now even if by 1%.

------
namdnay
The silliest thing about this road is that France already has very low carbon
electricity, only 7.2% of electricity produced in 2018 was from fossil
fuels...

------
ctulek
This is not a fiasco, it is progress! I am sure they learned a lot. This is
how science and engineering works. We keep forgetting that. Next time, I am
sure they will do better.

~~~
bittercynic
It is a fiasco in the sense that it didn't work as advertised, or anywhere
close.

------
gonational
The fact an idea this stupid was actually implemented is fucking mind-blowing.

But, we should all be paying “carbon taxes” so that these same idiots can save
the world.

------
jostmey
When I walk through a forest, it is full of life. There are dozens to hundreds
of critters living above and below me everywhere I walk. When I walk through
developed areas, it is lifeless pavement. Anything that reduces humanities
footprint, leaving more land to Nature, is probably a good thing. I hope
people don't give up on solar paneled roads.

~~~
gbrown
If solar panel roads cause more waste and carbon emissions, while supplying
less actual power, I certainly hope we give up on them. The ecological
calculation requires science and engineering, not vague feelings about what's
probably good.

------
Erudite_Genius
Solar roadways failed for the same reason Tesla will NEVER outsell gasoline
cars: bad technology that's orders of magnitude worse than existing solutions.

That being said, a huge leap forward in technology would make BOTH viable.

A better road-based electricity generation plan would have been to use
piezoelectric panels instead of photovoltaic ones.

