Solar highways

Integrating road networks and power networks

The US Department of Transportation has awarded funding for building a 'solar highway' prototype. A solar highway contains photovoltaic (PV) modules covered with bulletproof glass as a road surface. The surface also contains a grid of LEDs that can light the roadway, draw lines, and flash warnings that react to traffic sensors. Apart from supplying power for the LEDs and sensors, the energy generated by the PV modules will also be used to heat the highway when required. The remaining energy can be used for houses and businesses alongside the road. If this systems works as projected, it could well make power stations and power lines superfluous. According to an article on Matter Network, covering all American roads with this system would produce an annual yield of energy three times as large as the entire U.S. energy consumption in 2006.

A utopian idea

Anyone reading about such a project with a critical — or downright sceptical — mind may question the claims and even wonder how this idea ever managed to receive funding. After all, PV manufacturing companies are already hard-pressed to create PV modules that are efficient and affordable; their task will become even more complicated if those modules also have to withstand the weight of heavily loaded vehicles. And how will the cost of one square meter of this ‘intelligent highway’ ever be in the range of one square meter of simple asphalt or concrete combined with a conventional PV panel? And what about the production intermittency caused by passing cars and trucks?

The idea to replace the complete system of power plants and power lines with these so-called solar roads sounds utopian. How will such a network be balanced? How will daytime production be stored at night? How will production and consumption variations over the year be flattened out? Without power cables along the road and extensive storage facilities — both of which are very costly — the whole concept appears impossible.

Funding proportional to potential

But then again, the funding by the US Department of Transportation is only $100,000. That is a small amount of funding for testing new ideas — however harebrained they may appear at first sight — that just might stimulate workable, creative innovation. One day, one of these apparently crazy ideas just might make it into the mainstream market.

And there is certainly some interesting logic in the solar highway concept. Take for instance the idea of making multipurpose use of the huge volume roadway surface that is otherwise lost for any purpose other than transport. Actually the idea of combining electricity production and distribution in one network is rather elegant. And isn’t it a fact that the large majority of energy consumers are located along roads? Moreover, if EV’s ever replace conventional petroleum powered vehicles, the idea of producing electricity 'on the road' becomes even more attractive.