Think about your average solar collector. Even if you have no idea how the dang things work, you know that:

• They are flat
• They are black
• They don’t work in the shade.

What else fits that description? With a few exceptions on the shade angle, the world has a lot of asphalt baking in the sun. A lot. Anyone who’s gone barefoot in the summer knows how hot a street can get. With that much surface area, you would only have to convert a tiny fraction of the solar flux into useable energy to make a huge difference.

So, come on, science (or maybe this is one for the engineers), give us a way to turn all those square miles of asphalt into cheap, low-efficiency solar collectors.