EEVblog #632 - Solar Roadways Are BULLSHIT!

[G7PSK]

I made the assumption that they would have to lie flat on a concrete bed, but concrete is not going to be flat for long as the soil underneath moves the concrete will ripple and crack taking the tiles with it, they could of course put an elastic layer between the supporting concrete and the tile but in itself will lead to flexing and cracking of the tile and if you look at places in the road where heavy vehicle regularly brake the surface takes up a wavy surface looking like sand where the tide has gone out concrete roads do the same but not as fast.

[Zad]

Just imagine, a kid gets hold of a $5 spring loaded centrepunch. That could be a very expensive 5 minutes...

I'm surprised they need any engineers at all, they seem to know it all!

[nsayer]

Of course, Dave did touch on this in his video, but the most obvious deal-breaker is that his numbers - dismal though they are - completely leave out the fact that these things are going to be shaded a substantial fraction of the time by big honking vehicles (no pun intended). Yes, the vehicles move, but they cast a shadow one place or another. Duh.

[AlfBaz]

From that page we can learn where they stole that idea from!

hmm...
I thought for sure they got it from Mr J

[SeanB]

Largest overload that was taken off here was 130 tons over......... Not 130 tons, but that over the legal max of 66 tons, wonder just how the straddle carrier and the dockside crane survived that massive overload on them from the 2 containers involved.

The most common abnormal load generally runs at around 5 tons per wheel, using up to 100 axles to spread the load. Seeing as that can flatten the wave trough out on the road when passing over it I would hate to see what happens to glass.

[Stonent]

Another thought, studded snow tires. I don't think the glass would hold up.

[deth502]

Another thought, studded snow tires. I don't think the glass would hold up.

who would need studded snow tires when we live in a Utopian world with magical snow melting solar roads??

[mtdoc]

Dave,

Good on you for debunking this freakin' BS.

I'm not sure if others have pointed this out but another reason why it is even worse than your analysis is the severely detrimental effects of temperature on PV output. Without airflow behind a panel, output will quickly decline as it heats up.

A couple of other points:

Optimal fixed angle for year round PV deployment is generally close to the sites latitude. So only at or near the equator would a solar roadway be at optimal angle. At northern latitudes, especially in winter, a flat panel will harvest very little.

"Feed in tariffs" in the USA vary widely from state to state and between utility districts. In many places there is none at all!

[Stonent]

Another thought, studded snow tires. I don't think the glass would hold up.

who would need studded snow tires when we live in a Utopian world with magical snow melting solar roads??

 

[EEVblog]

Although Dave criticised the Solar roads on the basis of the actual solar panel efficiency, as you would expect an EE to do. I think it is becoming increasingly evident that the concept is flawed on so many levels that the efficiency is actually one of the lesser ones.

Absolutely.
My plan when I started shooting that video was it was going to be a "Top 5" reasons the idea is BS. Hence my listing 5 major things.
Solar output was only going to one of them, and a pretty random choice to do that one first.
But it kinda morphed into a standalone video and longer than expected.

Technically, solar output is not a showstopper in terms of using it for a road, it just makes it ridiculously bad value and poor design. BUt of course, right there isn't showstopper in practical terms of it ever being viable. Not to mention (ironically) ecologically unfriendly.

[EEVblog]

I'm not sure if others have pointed this out but another reason why it is even worse than your analysis is the severely detrimental effects of temperature on PV output. Without airflow behind a panel, output will quickly decline as it heats up.

Absolutely. I was generous by not getting into that.

[steves]

If they only put the panels on bends that face into the sun and inclined them NASCAR style, would that help? If not, they should do it anyway.

[EEVblog]

If they only put the panels on bends that face into the sun and inclined them NASCAR style, would that help?

Sure it would help, but not even close to being enough to make it financially viable.

[miguelvp]

If they only put the panels on bends that face into the sun and inclined them NASCAR style, would that help?

Sure it would help, but not even close to being enough to make it financially viable.

Unless it was really a NASCAR track and the cars where crashing all over the place driving the viewer's rating up so they will make more money out of commercials (but yeah there is the thing about high speed accidents, I guess they preached they want to save lives and if they where installed a lot of people will be alive now)

Still you can make money by making racing even more dangerous (although we all know the drivers keep pursuing safety) hmmm, maybe if they got a F1 driver to promote their roads?? 

[george graves]

Dave, looks like your video reached it's peak.  Care to share the stats on it?

I think you were a bit too late, a few weeks earlier, and you're video may have gotten much more views.  No? 

Now that it's "funded" - well, "flexible funding" - and they don't have to deliver a darn thing...All they have to do is post up once a week, and in a year or two, all will be forgotten.  2.2 million....

Stay tuned, my next kickstarter is "SOLAR FREAKING SIDEWALKS"  - heck, at least you might be able to walk on them, and minus the bubble gum, they will power a small city!

[Bumbi]

Guys,

I wanted to read all the previous post before saying anything but I see that swearing and speculating about who's gonna steal the money is done more often than commenting the actual issue.

All I wanted to say is that I find it rather disappointing to see engineers with zero faith and arguing endlessly against something. Especially if it's an unfair argument. This is the quality of an engineer who can only do what's been done before. Where will you hide when it will be done in 10-15 years time? Are you the ones who make up problems or the ones who teach the rest how to do stuff?  Have faith my friends, it there's a problem then solve it, figure shit out.

J

[george graves]

Guys,

I wanted to read all the previous post before saying anything but I see that swearing and speculating about who's gonna steal the money is done more often than commenting the actual issue.

All I wanted to say is that I find it rather disappointing to see engineers with zero faith and arguing endlessly against something. Especially if it's an unfair argument. This is the quality of an engineer who can only do what's been done before. Where will you hide when it will be done in 10-15 years time? Are you the ones who make up problems or the ones who teach the rest how to do stuff?  Have faith my friends, it there's a problem then solve it, figure shit out.

J

And your credentials are?

[rob77]

Guys,

I wanted to read all the previous post before saying anything but I see that swearing and speculating about who's gonna steal the money is done more often than commenting the actual issue.

All I wanted to say is that I find it rather disappointing to see engineers with zero faith and arguing endlessly against something. Especially if it's an unfair argument. This is the quality of an engineer who can only do what's been done before. Where will you hide when it will be done in 10-15 years time? Are you the ones who make up problems or the ones who teach the rest how to do stuff?  Have faith my friends, it there's a problem then solve it, figure shit out.

J

Engineer is supposed to engineer/design/build something what was invented before ! the scientists are supposed to invent things ! all the good engineers know the limitations of technology and are supposed to engineer/develop products accordingly.

If an engineer believes he can overcome the laws of physics (and therefore the limitations of technology) - that engineer is either undereducated or stupid. (and should return his degree immediately )

so please stop posting nonsense - the solar roadway guys are claiming they're ready for production with the current technology - and that's impossible with today's technology.

no-one says in 20-30 years we couldn't have materials which would make it possible... but even then it will be economically not viable to build freaking solar roadways.

[Bumbi]

George,

what do you care for my credentials? I don't think makes any difference in the light of what I said. In my country anybody can get a degree as electrical engineer who can read and write so I don't see the point in "comparing our letters". But if you really want to know I have an abandoned IT engineer course behind me. I also spent some years on a university as pianist. I hope very important and relevant piece of information will help you to understand what you didn't get for the first time in my post.

[EEVblog]

Have faith my friends, it there's a problem then solve it, figure shit out.

Ok. For starters, tell us how you will solve the problem of return on investment on solar panels in a road under the most horrible unoptimised conditions possible.
Because we have many smart engineers here, and it seems that none of us can come up with solution. I can't.
The numbers don't lie, they are an order of magnitude away from being even ballpark viable on that aspect alone.

And that's just one issue with this project, there are literally dozens of others that look to be show stoppers.
If I had an idea that could salvage this project, then I'd be shouting it to the world, because that's what engineers do.
But there isn't a clever solution to this, the entire idea is fundamentally flawed.

This isn't a lack of faith, it's a lack of confidence build very strongly on basic engineering principles.
If it's faith you want, go to church.

[Bumbi]

Guys,

can you not come up with 10-15 examples to something that we have now and seemed impossible before? Do you need help?

Rob, I'm not saying that it is possible. Maybe it's not, I can't tell from sitting in a chair (and I don't think anybody of you can either). What I'm saying it that I consider it primitive to make up stuff as part of an argument against something just because you don't like the idea or you THINK it's not doable. Even worse to blow somebody else's trumpet without doing your OWN calculations and experiments. This thing didn't get a fair trial. Normally before I say that something is impossible I try first. Not once, fifty times. (How many times did you try to ride your bike before it actually happened? Once? I don't think so. And that's so easy that even a 5 years old can do that.) And then all it means that _I_ can't do it. This is how things go forward. Nobody believes in something, then on dude makes it happen. Then the rest learns. You are the rest. I expect engineers to be way more creative. This is what I'm saying. And I'm not arguing about this, I'm saying it as my opinion.

[EEVblog]

Dave, looks like your video reached it's peak.  Care to share the stats on it?
I think you were a bit too late, a few weeks earlier, and you're video may have gotten much more views.  No? 

Of course I should have done it earlier, but it took some working up to it. So it is what it is.
The basic stats are visible. On top of that it is my most shared video ever. Not much else to tell.
Audience retention rate is above average over the entire video.

[electromatt]

Hi Dave, great vid as usual

Can you put some sense into this thread over on whirlpool https://forums.whirlpool.net.au/forum-replies.cfm?t=2263747&p=9

I know you have an account

[Bumbi]

Have faith my friends, it there's a problem then solve it, figure shit out.

under the most horrible unoptimised conditions possible

Create less horrible conditions. If pointing the LED up is horrible because it wouldn't be visible then how about not pointing them up as a start? Done. One problem less. And here I'm not saying that I can eliminate all the problems. I'm saying that you need to try better if you want to argue the feasibility of the project.

[/quote]
the entire idea is fundamentally flawed
[/quote]

Let's just say that you don't know how to make it happen.

I think you calculated the return as $33/m2/year. in your calculations a road is 8m wide. A 150km piece of road, let's say a test road would return $40 million in a year. And let's say it's shit. The worst road ever. You can't stop on it, you can't see the LED's and all that. $40million as return in a year is surely enough to try it again. And again and again.

[max_torque]

Guys,

All I wanted to say is that I find it rather disappointing to see engineers with zero faith and arguing endlessly against something. Especially if it's an unfair argument. This is the quality of an engineer who can only do what's been done before.

As an engineer who certainly doesn't like to only do what has been done before, i find some important issues with your assertions!

In the "real world" engineering is a compromise.  Today, in 2014, we have such understanding of our environment and physics, that practically, we CAN do almost anything we set our minds to.  The issue is not therefore of CAN we do something, but should we do something, and that includes many more non engineering decisions and often politics, semantics and even idealistic principals!.


An example:

  You need to buy some milk.  I suspect you either walk, ride your bike, or most probably, drive your car to the shop to buy some.  Why don't you take a helicopter to get some, it would be much quicker?  The answer (of course) is that the vast majority of people cannot afford to own a helicopter, even though "helicopter technology" is proven and now relatively mass produced.  That doesn't make "Helicopters" pointless, or make people who don't use helicopters to get their milk luddites!!



So, the principal issue with Solar roadways is simple:

"Due to the compromises necessary in the design to make these solar panels work under roads, for any given investment, it will always be better (higher ROI)  to spend that money on conventional solar systems"

This has nothing to do with the technology or physics, or engineering or whatever of the devices, but is a simple fact of the (capitalist)world we live in.