Solar Panels – The Asphalt of the 21st Century?

With the increased focus on renewable energy, solar panels, which are more formally referred to as photovoltaic cells, are becoming more widespread in:

• Roofs of homes, reducing the amount and cost of purchased electricity,
• Roofs of hybrid cars, powering its air conditioner and thus placing less drag on the gasoline-powered engine, and
• Calculators and small electronic devices.

There are thoughts of using a wide areas of land to support a large amount of solar panels to power entire cities, but where is the land? How about the highways? Could solar panels be placed along the roadways as sound barriers? Or, could the roads themselves be made of solar panels? This article seeks to explore the potential for such a solution.

Solar panels are already in use on our roads. They are:

• Attached to and power traffic warning signs on the side of the road, and
• Near interchanges of interstate highways in areas as large as 3,000 square feet feeding the electric grid and powering the highway’s lights at night.

Solar Panels or Solar Roads?

Some experts are proposing that the roads themselves should be built out of solar panels. Products are being designed to construct structurally sound rows of solar panels that road vehicles (including trucks) can drive on. These road will collect solar energy to create electricity to supply power to homes and businesses. These panels consist of three layers:

• A top road surface layer of high-strength glass that provides traction,
  

  Solar Roadway Panel

• An electronics layer (i.e. an array of solar cells) that collects the energy, and
• A base plate layer distributes the power.

In addition to collecting solar energy, these “road panels” provide other functions, including:

• Containing LED lights powered by the sun, they can act as road and warning signs,
• Gather heat so that they can serve to melt snow and ice, and
• As a source of electricity beneath cars, they can facilitate the charging of electric vehicles at roadside stations.

Each mile of these types of solar roadways are estimated of being capable of supplying enough power to meet the daily electricity needs of as many as 500 homes.

Characteristics of Solar Roads

Despite the potential advantages cited above, there are several challenges to overcome including:

• Cost: Each panel costs $7,000 and it would require billions of them to cover the U.S. roadways. Additionally, there will be huge time and money expenditures necessary to train maintenance crews. The most reasonable approach points to small pilot projects over several years.
• Durability: Questions exist regarding the kind of punishment these panels can absorb over an extended period of use and the impact of their failure should they be a primary source for traffic signals.
• Maintenance: Not only would repairs be costly as compared to fixing asphalt roads, but there is yet to be developed a proven process for keeping the road surface clean.
• Dependability: Cloudy days combined with the fact that current solar power technology is inefficient (solar panels convert 14 percent of available energy into electricity), offers more questions than answers regarding the dependability of solar energy. For this reason, most view solar energy as part of the solution rather than a potential sole or comprehensive source of power.

Thus, although this technology is not ready today, the concept of a solar highway warrants further investigation, either because these challenges can be overcome or in addressing these challenges solutions will arise that will expand the role of solar energy in areas not yet contemplated.