Solar Roads

[svetz]

A continuation of the topic out of the Traffic powered wind turbines thread so as to not derail that thread further.

Warning: A topic not for the faint of heart as most of the vocal community believes this is a stupid idea, so if you post a strong opinion you'll be most likely be challenged. Please be respectful and don't get yourself banned.

Some of the Solar Road disbelief seems to stem from this youtube shock-jock:

He's made a number of videos about how stupid they are. Much of that assertion is based on a comparison that maximizes watts by putting panels on a rooftop at the proper angle rather than flat on a road that cars/trucks drive over. And that's true! But it also assumes that rooftops are available or that weather conditions allow over-road/canal placement. It also doesn't consider the costs of roads or how embedding solar into them affects the costs. Adding solar to a road may offset the cost of the road to the point where it is more economical to build solar roads.

But, when you take other factors into consideration, the economics of putting them into the road might make sense. The factors that come to mind are:

• Cost estimates to build a solar road at $1/sqft with mature technology versus current road costs of $3/sqft (largely due to increasing costs for asphalt and concrete, synthetic roads are coming regardless as to whether they're solar or not).
• Roads typically have power lines running along with them, making grid access easy.
• Even at reduced power output due to an inefficient tilt, at southern latitudes, they are still more cost-effective than natural gas and produce less CO₂.

So, where does the youtube video get it wrong?

• From the standpoint he's just having fun and entertaining people it's fine. What's wrong is it's misleading and it's harder for technologies to advance and be trialed if public opinion is against them. AFAIK, Solar Roads are not a mature technology ready to be deployed. But I do believe the economics are interesting enough to warrant small projects (like Spain's) to help advance the technology. Even if solar roads don't work out, they will still advance composite roads.
• He makes a big deal about it, but the expected STC energy rating is only 10% less than roof-top panels (2:40) at no-tilt.
• It's only 9 kW because it's a test array. That's a good size for a test IMO.
• At the end of 6 months, it's supposed to be dug up and analyzed. It's an experiment designed to further the science to see if the technology can be made practical. It's an investment.
• "1/3rd the output for 9x the cost", which was a trial in France and compares to roof-top costs rather than road-construction costs.
• He says the cost is far greater at 30K euros than a rooftop array, but in USD that's $36,600 for the equivalent of 9kW array, or $3.66/W which is only about 50¢/w over what you'd pay for rooftop solar In my HVHZ area, and you get a road - so might be a bargain.
• "We have results from everywhere else!" Not really, all of those are test trials with different materials, each generation hopefully better than the last. If we gave up after the first failure then we wouldn't have lightbulbs, footsteps on the moon, flight, etc.
• "It doesn't matter how mature the technology is" - this is primarily based on laying panels flat. Yes, you take an energy hit by not optimizing tilt. But, that's not as big of an impact closer to the equator. Even at the 15% loss in Sydney, it's still has a lower cost than natural gas. It also doesn't consider the cost of the road.

Will the Catalonian project show positive economical results? Probably not.
Should they cancel it? Heck no, can't advance technology without trials.

 

[Steve_S]

I am of a different camp on Solar Pavements.
The most obvious issue with Solar Pavements is location / region / geography. Would not make a lot of sense in Moscow or Nome Alaska would it.
Doing roadways with Cars & Trucks presents a heap of issues to resolve, that I feel is fairly obvious and yet again there is also the environment the road is located in. The wear & tear, maintenance issues and all of that has some way to go yet.

Pavements are a common term - it does not specifically mean asphalt/tarmac. Cobbles, Tiles, Bricks are all "pavements". Almost all urban areas are paved for vehicles & pedestrians alike. Solar Tile Systems would most likely be suitable for Pedestrian Areas such as Plaza's, Sidewalks & Bikeways which could power the street lights and other services. By starting with pedestrian areas the R&D and Testing can be accomplished at varying scales and with the various types of "Tiles" being developed. There are even tiles which are also Permeable to allow rains through to the soils below which is yet another regreening aspect to consider for the future.

People have Paved driveways for ages with cobbles & then asphalt. Many areas are seeing people switch from asphalt to other materials like cobble-stones and permeable tiles and more. With EV's coming into play now and more people installing solar power to supplement or replace their grid power, every watt counts. Now imagine a 200 foot long 14' wide solar driveway (2800 sq ft) in the sunshine could generate a lot of juice.

Like those Ding-A-Lings in California... For over a DECADE many folks have repeatedly / endlessly suggested that they install Solar over the water canals/aqueducts to not only help prevent evaporation (which is very huge) and to generate it's own power to operate the pumps and management systems + to push the surplus to the grid. It only JUST Occured to the Californian Government that it may be a good idea ! GEEZ, a tad slow on the uptake.... holding the door while brains were being given out or what ? Seriously.

 

[HRTKD]

Can it hold up to a snowplow scraping snow/ice off of it?

 

[Q-Dog]

Can it hold up to a snowplow scraping snow/ice off of it?

Might as well heat them too, so the snow will melt off.

 

[HRTKD]

Might as well heat them too, so the snow will melt off.

Three day blizzard, no sun. How's that going to work? I suppose if the embedded panels are on the grid they'll just draw power from the grid.

 

[svetz]

SNOW! OMG! Catalonian winters are cool along the coast and colder in the interior. The Pyrenees Mountains get frequent snowfall during the winter. Snow occasionally falls along the coast, but it melts quickly. ... Winter high temperatures along the coast average in the 50s, with average morning lows in the 40s. Not much snow from 30° N to 30° S; but it varies by country and altitude. My city doesn't have snow plows (global cooling hasn't been predicted since the 60's AFAIK), although mother nature does occasionally salt the roads. But yeah, point taken, they might not be for everywhere.