Solar photovoltaic technology is getting cheaper, more efficient and more resilient all the time. And solar road stud markers are widely applied in the whole world. But it still doesn't make a good replacement for asphalt. After years of trial projects, a handful of “solar roadway” projects around the world are revealing just how expensive it is to use roads, rather than rooftops and empty fields, as the world’s future solar surface. While the concept quickly gained broad public support — and funding — most energy experts were skeptical of the solar roadways from the start. Ars Technica first reported this week on the challenges facing this "oddly popular idea."
In France, the world's first solar roadway, dubbed WattWay, opened in 2016. The one-kilometer stretch of toughened PV panels, built by European road construction giant Colas, cost €5 million ($5.2 million) to build, and was expected to supply 280 megawatt-hours of energy annually, or about 767 kilowatt-hours per day. These metrics brought the cost of WattWay’s silicon resin-strengthened PV panels to €17 ($20) per kilowatt-hour, or about 13 times as much as the €1.30 ($1.53) per kilowatt-hour for comparative large-scale rooftop installations. But according to a January 2018 news report, WattWay only generated about 409 kilowatt-hours per day in the first year of operation, roughly half its expected daily output, further eroding its cost-effectiveness.
The U.S. version of WattWay has been championed by a company called Solar Roadways. More substantial support came in the form of a $100,000 U.S. Department of Transportation grant in 2009 to study the technology’s feasibility, along with a $50,000 GE Ecomagination grant in 2010 to further that work. Then, in 2011, DOT added a $750,000 grant to fund a second demonstration array with solar cells, LED lights, and a heating system built in. From my point of view, solar road stud marker is enough to solve the environmental problem and can avoid most problems of solar roadway. We still lack of necessary technological support so the solar roadway need a long way to go. Solar road stud markers are good start of the wide application of solar products.