UNIVERSITY of Rhode Island researchers are examining ways of harvesting solar energy from roadways.
Asphalt pavements crisscross cities, and they absorb a great amount of heat, resulting in cities being warmer than nearby suburban or rural areas.
URI professor K Wayne Lee says this heat can be harvested and used to save on fossil fuels.
The team has identified four potential approaches, and are pursing research project to further each of these.
A simple idea involves wrapping flexible photovoltaic cells around the top of barriers dividing highways to provide electricity to power streetlights and illuminate road signs.
The researchers also looked at embedding water filled pipes beneath the asphalt to allow the sun to warm the water. This water could be used by nearby buildings, or for melting ice in winter.
A third alternative uses a thermo-electric effect to generate a small but usable amount of electricity. When two types of semiconductors are connected to form a circuit linking a hot and a cold spot, there is a small amount of electricity generated in the circuit.
According to URI Chemistry Professor Sze Yang, thermo-electric materials could be embedded in the roadway at different depths or locations, so the difference in temperature between the materials would generate an electric current.
In particular, he suggested using a family of organic polymeric semiconductors developed at his laboratory that can be fabricated inexpensively as plastic sheets or painted on a flexible plastic sheet.
The most futuristic idea is to completely replace asphalt roadways with roadways made of large, durable electronic blocks that contain photovoltaic cells, LED lights and sensors. The blocks can generate electricity, illuminate the roadway lanes in interchangeable configurations, and provide early warning of the need for maintenance.