Initial results are in for the solar roadway

[bsoft16384]

SolaRoad says that their solar roadway is doing "better than anticipated":
http://www.cbc.ca/news/technology/solaroad-generates-more-power-than-expected-1.3069371

However, the numbers look to be about what Dave calculated. The test site is approximately 70m² and generated 3000kWh over 6 months.

3000 kWh / 182 days / 70m² = approx. 230 Wh per m^2 per day

(Dave's realistic maximum was 380 Wh per m^2 per day)

This is from a 3.5 million Euro system, though obviously that includes R&D expenses.

Based on some numbers from NREL's PVwatts calculator (http://pvwatts.nrel.gov/pvwatts.php) it would take approximately a 7kW system (DC) to generate the same amount of energy in 6 months in the location that the solar road is located at (Krommenie).
I don't have exact numbers for Krommenie, but a 7KW rooftop PV system where I live would run around $15k-$25k installed.

[GodOfVolts]

 

[Mechanical Menace]

Missing the point, as ever. It's a test to see if the technology works. It does, so now we move on to applications.

It's a research project, not a prototype of a real product.

But the results show that it's not even efficient enough to power itself, so the tech doesn't work.

[wraper]

The point was to prove the road surface. It survived. Dirt and wear were about what was expected. As panels get cheaper and more efficient it will make more economic sense.

If it was to test surface, what was the point to install solar panels underneath? Even if solar panels become 100% effective and 10x cheaper, this thing still makes no economic sense. Actually, solar panels do not constitute majority of the cost of this thing.

These guys are now the world leaders.

In solar bullshit scam.

[EEVblog]

However, the numbers look to be about what Dave calculated. The test site is approximately 70m² and generated 3000kWh over 6 months.
3000 kWh / 182 days / 70m² = approx. 230 Wh per m^2 per day

Incorrect, it is 70m long, not 70sqm. I estimated about 1.75m wide.

[EEVblog]

The point was to prove the road surface. It survived. Dirt and wear were about what was expected.

A local resident said that it was closed for a lot of the winter due to the cracked panel, so wear may not have been fully tested.

As panels get cheaper and more efficient it will make more economic sense.

No it won't. Because the economics of roof/pole pot panels vs pavemet/road panels will stuff remains the essentially same regardless of what happens to the cost and efficiency of solar panels.

[EEVblog]

It's a research project, not a prototype of a real product.

Of course it is! 
They will not get any better efficiency out of this thing, so do the math on csaled up production costs vs roof/pole top and it still doesn't make any sense.

[coppice]

The point was to prove the road surface. It survived. Dirt and wear were about what was expected. As panels get cheaper and more efficient it will make more economic sense.

If it was to test surface, what was the point to install solar panels underneath? Even if solar panels become 100% effective and 10x cheaper, this thing still makes no economic sense. Actually, solar panels do not constitute majority of the cost of this thing.

You have to put actual panels there for it to be a useful test. You won't learn about the true amount of usable energy reaching the panels through the dirt without actual panels. As you said, the panels are not the major cost, so why would you omit them?

[coppice]

One area of the surface was broken, but I didn't see an explanation for what happened. Was that something unfortunate, or an indication that their surface was unreasonably weak?

[dexters_lab]

One area of the surface was broken, but I didn't see an explanation for what happened. Was that something unfortunate, or an indication that their surface was unreasonably weak?

"The tests have shown that large temperature fluctuations cause the glass coating to shrink, causing part of it to peel off in early winter and early spring. The coating has since been repaired, and engineers are in the "advanced stage" of the development of an improved top layer."

[Galenbo]

Missing the point, as ever.

The same guy again, redefining it to his own point. And ready to jump to another 'point'

It's a test to see if the technology works...It's a research project,...

No it is not. It's an attempt to receive millions of subsidies, based on an unscientific media campaign.

The point was to prove the road surface. It survived.

another 'point'
This one failed. The glass broke.

To give an example of another application, Toyota tried putting PV on hybrid cars. Dirt and wear were an issue. Now they use smaller panels just to run the air con on hot days while the car is parked.

Said the guy that did not calculate the cooling capacity of a system powered by some solar panels.
Ready to put a car out of the shadow, to get more cooling.

[Delta]

WTFFF is this shit?

Who on earth came up with the idea of putting PV panels on a road?  Or were they challeneged to come up with the most expensive and inefficient solar installation possible?


Hopefully there's no more such pathetic gimmicky projects planned, and the money can be spent putting panels on rooftops...

[daqq]

Missing the point, as ever. It's a test to see if the technology works. It does, so now we move on to applications.

That's not a particularly shocking revelation - solar panels work, you can make them as rugged as you want, encase them in whatever you wish...

The point was to prove the road surface. It survived. Dirt and wear were about what was expected. As panels get cheaper and more efficient it will make more economic sense. These guys are now the world leaders.

Well, yeah, they are the world leaders in placing solar panels on the worst possible surface possible and ending up with the highest price per watt available on Earth. I'm all for solar power, but the core question remains:

WHY WOULD YOU PLACE A SOLAR PANEL IN THE WORST POSSIBLE PLACE AVAILABLE RATHER THAN ANYWHERE ELSE?

Why not take a quarter or less of the funds needed for a full refit the US road system and cover Texas with cheap, more efficient solar panels?

[tom66]

To give an example of another application, Toyota tried putting PV on hybrid cars. Dirt and wear were an issue. Now they use smaller panels just to run the air con on hot days while the car is parked.

This is wrong. The panel on the Prius, and Nissan Leaf, only supplements the 12V system. The air con runs off the HV battery. The 12V is topped up from the HV battery via a DC-DC converter.
 
That poxy 15W peak panel might reduce some load on the car systems, but cruising down an average road uses 10-15kW so it's not going to make a big dent.

I'd argue most people would never see the option pay back (£300 for the Leaf), as given an average 60Wh generated per day, it would give you £3 in electricity costs back per year.

TBH the additional power required to carry the weight of the solar panel and charge electronics probably exceeds the energy gained from it.

Solar panels don't work on passenger cars, the surface area available is too small and the weight is too high. Maybe if the technology improves but I don't see it myself.

[Mechanical Menace]

Why not take a quarter or less of the funds needed for a full refit the US road system and cover Texas with cheap, more efficient solar panels?

Couldn't covering Texas power the world? Actually couldn't just shoving them on the rooves of most homes in Texas power the world?

[John Coloccia]

Put me in the "why are you putting them on a road???" crowd.  Stupid.  If you're hell bent on combining it with a road for some reason, wouldn't it be a bazillion times cheaper and easier to simply put them NEXT to the road, or over a road, where they can also function as lights, traffic signals, signs, etc?  If there wasn't so much money and effort involved, I would think this was an April Fools joke.

[wraper]

wouldn't it be a bazillion times cheaper and easier to simply put them NEXT to the road, or over a road, where they can also function as lights, traffic signals, signs, etc?

I've seen that quiet a lot... in Russia.

[Tallie]

Must admit "solar road" sounds cool...

[TerraHertz]

  <practical cynicism, about an insane idea>

+1 !

'Solar Roadways' concept sends me into fits of giggles. It's one of those ideas that's very useful, for flagging who are complete la la land lunatics.

I flatly don't believe they could be made robust enough to withstand heavy traffic + grit grinding, dropped stones and bolts, weather, etc, while retaining a non-skid surface at the same time as high optical transmission. Or that the energy cost of manufacture, installation and maintenance could be repaid by output in less than the operating lifetime. Also in the country it would be cheaper to put panels in fields beside the roads, while in the city they will be sunlight blocked by traffic/buildings most of the time...

Putting all that aside, can you imagine how much vandals and copper thieves would love these? Just look at the average train window or bus stop glass wall.

And lawyers. "My client's accident was entirely due to skidding on the solar roadway, and consequently we are sueing the roads authority for five million dollars for negligent endangerment of life."

[corrado33]

To give an example of another application, Toyota tried putting PV on hybrid cars. Dirt and wear were an issue. Now they use smaller panels just to run the air con on hot days while the car is parked.

This is wrong. The panel on the Prius, and Nissan Leaf, only supplements the 12V system. The air con runs off the HV battery. The 12V is topped up from the HV battery via a DC-DC converter.

Are you sure about the Prius? My lab partner, who I see every day, has a prius with a constantly dead 12V battery. I said that's ridiculous because you have a massive battery in the car that could be used to keep the 12V battery charged, but apparently that's not how it works. We got into this discussion when he said that he couldn't leave his prius at the airport for a 2 day trip because the battery would "die."

[tom66]

Don't know about later gen Priuses, but the first gen and second gen definitely use a DC-DC converter to charge the 12V. However, perhaps this is inactive when the car is off. The HV battery is not very big (a few kWh), and the 12V battery could be worn out too.

[tom66]

Don't know about later gen Priuses, but the first gen and second gen definitely use a DC-DC converter to charge the 12V. However, perhaps this is inactive when the car is off. The HV battery is not very big (a few kWh), and the 12V battery could be worn out too.

Most cars with traction batteries use an alternator, do maybe they switched at some point. While less efficient it's cheaper. It's a shame they need a 12v battery at all (even EVs have them, despite not hanging a starter motor) but there is so much invested in the 12v system they can't just ditch it or redesign so many components and systems.

It's not there for fun, or because of the legacy 12V systems, but rather safety.

In any serious accident requiring the airbags to be inflated, electric vehicles are required to trip a pyro fuse which disconnects the HV from the vehicle systems. The battery is fully isolated and floating from the 12V and chassis normally but this will also disconnect HV from the motor etc. This makes it much safer for first responders as they do not need to worry about cutting through high voltage cabling (in the Model S, the 400 VDC power for the air conditioning system runs along the side of the passenger's door frame, which could be easily broken by a jaw-of-life on that part of the car.)

But, if you disconnect the HV, how do you power hazard lights, airbags, doors, etc in a crash situation? The 12V provides this power.

I am certain in a few years Tesla and other EV manufacturers will replace the lead acid 12V with a lithium type, possibly LiFePO4 because of its greater tolerance of deep discharge and safety (the 12V battery is much more exposed and at risk of being punctured in the most severe accidents.)

It's also likely that as semiconductor switches replace relays in car systems vehicles will move to a 36~48V DC bus.

You are assuming they have a free choice of placement. Where in the world can local government build anything it likes anywhere it wants?

This isn't a good argument for putting solar on the road surface though, which is quite frankly a ridiculous idea for many reasons.   The embankments alongside many motorways would be an ideal place to install solar generation, if you insist on putting it along existing roads. Whilst the local authority may not own the land (I can't find any information on how much land they own beyond a road's tarmac, if any) I'd argue the land would have little expense given that it is unsuitable for nearly anything else.

[Jeroen3]

Oh no
http://m.engineeringnews.co.za/article/dutch-solar-road-proves-successful-moves-on-to-heavy-traffic-road-trial-2018-10-19

[SeanB]

Oh no
http://m.engineeringnews.co.za/article/dutch-solar-road-proves-successful-moves-on-to-heavy-traffic-road-trial-2018-10-19

Lovely fluff piece, probably only using a press release from the company. No rigorous comparison, and note that nobody on the staff wants their name associated with this article, which says nobody wants to be scuppered with this PR release masquerading as an article.

[coppercone2]

I like them because I don't like shit on the roof.

Also it makes life difficult for firefighters that want to cut the roof open. Shitty contractors mounting giant planes of glass on the roof as cheap as possible. What can go wrong. It can easily decapitate you.