Solar Roads: Can Streets Become Giant Solar Panels? | National Geographic

[Music] [Music] There is a project in the United States called solar roadways, which consist of concrete slabs including the solar cells, plus tempered glass on top of it. There's a quite similar project in the Netherlands called solar Road. A section on a cycle path was built about one year ago, but it's large concrete slabs, uh, which means that in fact you're completely rebuilding a road.

Our technology is different in that way, that in fact we just place our solar panels on an existing pavement. It does not require all that amount of preliminary works. The first idea was generated about 10 years ago, and it came from the feeling that in fact the road looks at the sky for more than 90% of the time. So, during this 90% of time, it can collect energy from the Sun.

We had a very good opportunity to work together with the people at the National Institute of Solar Energy. Their knowledge is photovoltaic technology; our knowledge is how to build roads. We worked together to find the solutions to the several problems we had to face to be able to integrate this technology on top of an existing pavement. We had pages and pages of questions.

What will be the grip on such a surface? Which type of material should we use? What is the ratio between the active solar surface and the road surface? How could we maintain it? How could we recycle? And so on. We tested several mixes of resins, glass birds, broken glass, and so on until we found a good compromise between the grip level and the light absorption.

These solar panels will produce electrical energy, and the use will be quite similar to the one you could have with traditional PV panels placed on rooftops. Uh, you can either connect them to the global electricity network, and in that case, you're re-injecting electricity into the network, or in case of more isolated locations, you can simply store the electricity in batteries and then use it for example, public lighting.

You could even also imagine in the longer term that you could also supply electricity to electrical vehicles, for example, either through a traditional plug or even through wireless technologies such as [Music] induction. The concept of solar Road tried to face two major problems of the development of solar energy.

The first problem is the lack of surface to produce enough energy, and the second problem is the cost of the systems. When you use a solar Road, of course, you take advantage of a large surface of the existing road, so most of the work has been done, and you just have to integrate your components on the road.

I can see two problems with solar Road. The first one comes from the heating of solar panels because when the temperature of the panels increases, the efficiency decreases, and the aging process is accelerated. The second one is that for the prediction of solar energy production, you will have to integrate the traffic road modeling to be able to predict accurately the electricity production.

Another interesting parameter to look at is the energy payback time, which is the time necessary to produce the same energy that has been used to produce the panels. So, it's a real challenge for [Music] engineering.