They paved paradise, put up a power plant

And to their dismay, the idea didn’t pan out:

One of the first solar roads to be installed is in Tourouvre-au-Perche, France. This has a maximum power output of 420 kW, covers 2,800 metres squared and cost €5 million to install. This implies a cost of €11,905 per installed kW.

While the road is supposed to generate 800 kilowatt hours per day (kWh/day), some recently released data indicates a yield closer to 409 kWh/day, or 150,000 kWh/yr. For an idea of how much this is, the average UK home uses around 10 kWh/day.

The road’s capacity factor — which measures the efficiency of the technology by dividing its average power output by its potential maximum power output — is just 4 percent.

Four hundred nine kWh per day? In the summertime, I can burn up 409 kWh in about a week, all by myself.

Now it is possible to get usable numbers out of solar:

[T]he Cestas solar plant near Bordeaux, which features rows of solar panels carefully angled towards the sun, has a maximum power output of 300,000 kW and a capacity factor of 14 percent. And at a cost of€360 million, or €1,200 per installed kW, one-tenth the cost of our solar roadway, it generates three times more power.

Fourteen percent still doesn’t sound like a lot, but the laws of thermodynamics assure us we won’t be getting numbers up toward 100 percent.

(Via Coyote Blog.)

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