Are Solar Roadways Working?
By some estimates, approximately 0.2–0.5 of the world’s land surface is covered by roads. That percentage is expected to increase by 60 percent by the year 2050, so it seems logical that constructing roadways out of solar panels would be a practical way to harness the sun’s energy to produce more electricity.
Not so fast. While constructing solar roadways was a hot-button topic several years ago, some scientists and engineers are pulling back on the idea, saying that while the roadways are producing electricity, they aren’t producing enough to make them viable.
How Solar Roadways are Made
Countries interested in this initiative have several technologies from which to choose. In the United States, a company called, oddly enough Solar Roadways, uses a top layer of glass covering an array of solar panels followed by a base that collects and distributes the electricity. A German company called Solmove uses a similar technology using tempered glass as has a Dutch company that produced the SolaRoad bike path in the northern town of Krommenie. In France, the solar panels are covered with a tough resin. China has devised its own version, using clear asphalt over the mid-layer solar panels.
The Idea Behind Solar Surfaces
Proponents believe the initiative is valuable for several reasons. First, the electricity produced can be sold to the local power grid, thereby providing renewable energy. Secondly, lane markings and road warning signs can be powered by LED lights built into the road while other cells can automatically melt ice and snow in winter. A third reason involves charging electric cars as the roadways would hold a charge, making it easier for vehicles to recharge at roadside stations.
Why Solar Road Surfaces are Controversial
Construction price is the biggest hurdle, followed by the fact that the short roads currently in use aren’t producing significant amounts of electricity. Some government officials deem that the money would be better spent by funding other technologies. The one-kilometer test road in Normandy, for example, cost €5 million to build. On top of that, the amount of electricity produced has not made such expenditures cost effective. Even the Dutch bikeway, which exceeded expectations in electricity production, came nowhere near paying for the cost of construction. This, however, was due in part to problems with the top part of the roadway, which deteriorated in inclement weather and had to be replaced in spots.
Where the Problem Lies
Most scientists believe the problem lies in the collection of solar rays. Efficient solar panels are tilted toward the sun to capture the most energy. Those that are even more efficient automatically change their orientation depending on the time of the year. The problem with solar roads is that they are fixed and have no orientation toward the sun, thus they don’t capture all of the sun’ rays. Ideally, reducing construction costs as well as bettter trapping of the sun’s rays are necessary before the olar road initiative can become viable.
