Are Roads a Solar Power Powerhouse?

Of all renewable energy sources, solar power generates the most attention. Perhaps it is because the sun is such a powerful permanent element that we can associate it with sustainability. The wind seems transient by nature and the sea is almost strange. Whatever the reason, solar power dominates the alternative energy market. One of the last avenues to explore has to do with transportation. More specifically, it has to do with solar powered roads.

In October 2009, Scientific American published an article about one Scott Brusaw who, with funding from the US Department of Transportation, was looking at various ways to make solar panels for roads. Brusaw is an electrical engineer by trade, but after being inspired by a wild comment from his wife, he decided to start Solar Roadways and build solar road panels made of glass.

The goal is for America’s vast highway network to generate enough power to power the entire country and more. But, at the time there were (and still are) two problems with the plan:

1) The cost would be enormous.

2) The type of glass required has not yet been invented.

Brusaw is unfazed. For the past two years he has been busy building prototypes and testing current glass technology. Much of this time has been spent trying to balance maximum transparency (for solar absorption) with grip so the vehicles don’t roll off the road. He has also tried to justify the funding. Many people believe that it would be easier and cheaper to build solar farms instead of incorporating solar technology on the roads.

For one thing, solar farms already exist and don’t require a lot of research and development. Solar roads, on the other hand, are brand new. R&D still needs funding, existing roads would have to be dug and new ones laid, and once this is done, it would be an important job to keep the technology up to date. Bursaw insists that the roads would pay for themselves, but the payback period has been estimated at 20 years and it is not unreasonable to expect technology to have advanced significantly in that time.

That is not to say that the idea is not solid. Researchers at the University of Rhode Island are also looking for ways to harness solar energy from roads. According to Science Daily, the team has four possible solutions:

• Wrap road barriers with flexible solar cells.
• Insert water pipes under the road to absorb solar energy. The heated water could then be piped to where it is needed and used for a variety of purposes.
• Embed thermoelectric material at different depths on roads and take advantage of the electricity produced by the difference in temperature.
• Replace the asphalt with solar power cells, which is very similar to Busaw’s idea.

Science Daily has also reported on the Pavener Project, which is in charge of Tecnalia and led by Grupo Campezo. Your goal is to collect solar energy from asphalt surfaces through a liquid-filled pipe system, which is similar to solution two from the Rhode Island research team.

So far, it appears that water-filled pipes are our best option for harnessing the untapped solar energy emanating from our roads. But that doesn’t mean we won’t soon be driving with solar-powered glass.