Roads are great for allowing us to get from here to there in a quick and safe way. But while they're waiting to serve the next vehicle, they're just lying around idle, making the world warmer with their dark surfaces.
But it doesn't have to be that way. A city in the Netherlands just installed the first bit of road capable of generating electricity: this bike path - of course it's a bike path! - has solar panels embedded in the surface, beneath a protective glass layer.
The photo above shows a section of the bike path being installed. Only half of it has the solar cells embedded in the surface; I'm guessing the other half is there for comparison: since this is the first of its kind, the people who built it will want to observe how it does under real-life circumstances.
The top glass layer is roughened to give enough friction to ride on, so the surface doesn't look much different from ordinary concrete surfaces like that of the footpath tiles;
The SolaRoad project is a collaboration of the Dutch innovation incubator TNO, the technology company Imtech, the infrastructure construction company Ooms, and the government of the province of North Holland.
For all the powerhouse participants, the first stretch of solar-energy generating bike path is only 70 meters long - you could coast over the whole thing without pushing your pedals at all. But the hope is that this will be the initial part of a whole network of energy generating roads that can power at least the street lighting and road signs, and eventually also the homes in the neighbourhood.
It's certainly true that there is a whole lot more surface on roads than on rooftops. And where space is at a premium, such as the densely populated Netherlands, it makes sense to put all the available surface to work.
SolaRoad, the road that generates electricity from sunlight. from Mattheus Bleijenberg on Vimeo (In Dutch, with English subtitles).
In the US, Solar Roadways has proposed a similar idea, their Indiegogo campaign (the one with the snazzy "Solar FREAKIN' Roadways" video) raised over $2 million, or twice as much as they had aimed for. Apparently it's an idea whose time has come.