Highway noise barriers are a necessary evil. We put up with their ugly concrete or metal facades because they protect the neighborhood from the din of traffic, but possibly they won't be quite as ugly for much longer.
A stretch of highway in the Netherlands now has noise barriers that are easy on the eye and have the considerable side benefit of generating solar power. The barriers are made of special colorful translucent solar panels that look a little like giant stained glass windows.
The key to the panels is a technology called "Luminescent Solar Concentrators" that can generate power even from the low-light gray conditions often found in Northern Europe. The LSCs receive the light and guide it in concentrated form to traditional solar cells at the sides of the road barriers.
The LSC panels were developed by researcher Michael Debije at the Eindhoven University of Technology. "Further benefits are that the principle used is low cost, they can be produced in any desired, regular color, is robust, and the LSCs will even work when the sky is cloudy," said Debije. "That means it offers tremendous potential."
Previous LSC panels were plagued by a problem where they would reabsorb the light as it was guided toward the solar cells, severely diminishing the amount of power generated. A paper published in Nature in March showed how Debije and his team have overcome the problem, making the panels a commercially viable product. It's part of assessing the feasibility of generating electricity using solar cells integrated in noise barriers or what they refer to as SONOBs (Solar Noise Barriers).
Since April 10, two test panels have been installed alongside a stretch of the A2 highway near Den Bosch in the Netherlands. The two small 5 meter by 4.5 meter panels also have regular solar panels as a control and if the experiment is successful could be put to widespread use. Early results show 1 kilometer (.6 of a mile) of energy-generating noise barriers can produce enough electricity to power 50 households. Testing in an outdoor environment will not only test the technology but also allow the designers to see how the semitransparent panels stand up to real world problems such as vandalism and maintenance requirements.
"Our practical test is a simple sum, through which we're investigating the ways solar cell technology can be integrated in a robust and visually attractive way," says Stijn Verkuilen, project leader at Heijmans, a Dutch construction company and project partner.
Other partners in the SONOB project are TU/e, Van Campen Industries, SEAC, Airbus Defense and Space Netherlands and ECN. The tests are supported by the municipality of 's-Hertogenbosch, Willemspoort, SPARK campus, the Ministry of Economic Affairs, and Scheuten.