Six months and 150,000 bicyclists later, the SolaRoad is considered a success.
A 230-foot bike path over embedded solar panels produces enough energy for a single-person home – a good start at 3000 kilowatt-hours. The test path is in the Netherlands near Amsterdam.
"We did not expect a yield as high as this so quickly," says Sten de Wit, a spokesperson for SolarRoad.
The idea is simple: why not turn some of the millions of miles of roads drenched in sunshine into solar panels? It could power street lights and traffic systems and in time, even electric cars and households.
You can barely see the solar panels beneath the cyclers. The other side of the road is left as is, as a "control" in the experiment:
While a flat solar panel is 30% less efficient than those at an angle or rooftop, there’s plenty of surface to make up for that.
A group of engineers stepped to the challenge of designing a solar road that repels dirt, resists skids and is strong enough to bear buses and trucks. The result: prefabricated concrete modules topped with a translucent layer of tempered glass covering the solar panels underneath. Solar panels are connected to smart meters, which optimize their output, and feed electricity to street lighting or the grid.
While cyclists have "hardly noticed it’s a special path," engineers are improving the top layer because the glass coating shrinks with big fluctuations in temperature. Parts of it have peeled off in early spring and early winter.
The project is a public-private partnership between the Dutch province of Noord-Holland and engineering firms TNO, Ooms Civiel and Imtech. It has a $3.9 million budget.
Solar Roadways in the US
In the US, a startup called Solar Roadways raised an amazing $2.2 million last year through crowdfunding as well as $850,000 from the US Federal Highway Administration for a pilot.
Although paving roads with solar is also their goal, they are starting with parking lots, driveways and sidewalks.
Their solar "bricks" are octagonal