The Roads Must Roll

The thing that amazes me about the environmentalist movement is how easily they embrace what turn out to be terrible ideas. Not just ideas that are bad for the economy, but often ideas that bad for the environment. Corn ethanol. Food miles. CFC bulbs. Carbon offsets. Geo-engineering. Zero Population Growth policies. Plastic bag bans.

Well, we have a new one: solar roads. The idea is that we replace a road with solar panels secured underneath safety glass. And this will … something.

Coyote Blog has the rundown on a prototype solar road that is a fiscal nightmare:

In the US, we pay about 12 cents a KwH for electricity (the Dutch probably pay more). But at this rate, in 6 months, the solar sidewalk has generated… $360 of electricity. Double that for a year, and we get $720 of electricity a year.

How much did the sidewalk cost? The article doesn’t say. You will find this typical of wind and solar articles. If they quantify the installation cost, they will not quantify the value of power produced. If they quantify the power produced, they will never quantify the installation cost. This article says the installation cost was $3.5 million, though I suppose one should subtract from that the cost to build a similar length concrete bike path, but that can’t be more than $100,000 for 230 feet. They say they are getting 70kwh per year per square meter, which is $8.40 worth of electricity per square meter per year. Since regular solar panels – without all the special glass overlays and installation in the ground and inverters and wiring – cost about $150-$200 per square meter, you can see this is a horrible investment.

He points out, quite correctly, that a road is one of the stupidest ways you can deploy a solar panel. First of all, the panel is pointed straight up, instead of south toward the sun, cutting its efficiency. Second of all, you literally have things passing over it all day, blocking out the sunlight (and, I note, causing large sudden voltage changes that can’t be good for the electronics). And I would add that having two layers of safety glass means you are blocking out some of the light the solar panel needs to absorb. And it’s not clear that a solar road will either be as durable as a regular road or as safe as one (do you want to ride your bike on glass during winter?). And you’ll have to find a way to keep the glass clean or your efficiency will drop even further.

The argument in favor is that it replaces asphalt, which is an energy-intensive product. Fair enough. But solar panels don’t just fall from the sky. They are also energy-intensive to produce. And they are energy-intense to maintain and replace, especially if you have fucking cars driving over them. They also point out that replacing our roads with solar panels (at a cost of about $50 trillion) would provide a enough energy to power the entire country since we have a huge number of roads. Again, fair enough. But lack of space isn’t the biggest problem with solar power right now. Energy storage is. They also make pie-in-the-sky claims that solar roads can power illumination at night or melt snow during winter. But that again gets into energy storage issue. I’m not sure how these road are supposed to collect enough energy to melt snow when they’re covered in … you know … snow.

Solar panels on roofs are a shaky enough prospect. I think they are gradually getting more feasible but are still hung up on the energy storage problem (and no, giant lithium ion batteries are not a solution). But putting solar panels in roads has to be one of the dumber ideas yet to emerge from the green mind. And yet a startup in the US has raised over $2 million for this nonsense.

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