French solar road branded a failure

French solar road branded a failure

The world’s first solar road in Normandy, which opened in 2016, has failed to meet expectations, raising questions about the idea of solar roads.

The 2.8 square km of solar panels is partly damaged beyond repair and the 1km-long road did not produce the power the developer Wattway had promised.

Panels were worn out by vehicles and joints between the panels were shattered. Wattway was accused of not accounting for leaves, shade, dirt and the weight of tractors that used the rural road in northern France. Storms also blew its circuits.

The flat cells on a road makes the panels less efficient than those tilted towards the sun.

Wattway originally said the road would power 5,000 households.

“If they really want this to work, they should first stop cars driving on it,” said Marc Jedliczka of the Network for Energy Transition, which promotes renewable energy.

Politicians were too hasty to push the project into operation at Tourouvre-au-Perche near Alençon without studying its cost-effectiveness, Jedliczka said. “It confirms the total absurdity of going all-out for innovation to the detriment of solutions that already exist and are more profitable, such as solar panels on roofs,” he was quoted saying by France’s Le Monde newspaper.

The French government provided around €5 million for the project and the solar road was inaugurated in 2016 by Ségolène Royal, then environment minister and the former partner of the Socialist president Francois Hollande. She promised a 1,000km network of solar-powered roads.

The state investment would have helped to subsidise numerous, cheap rooftop panels across the country.

The rural road was intended to produce 790-kilowatt-hours per day.

The surface created so much noise that a 70km/h speed limit was imposed. The feeble output of the road matches challenges faced by less-high-profile experiments in “solar roads” elsewhere.

The Normandy road was expected to produce 790kWh per day, but the first year’s energy production was 50 per cent per day of what was expected, with less than 150,000kWh produced in the first year. In the first half of this year, the road produced only 37,900kWh.

Wattway said it would raise €10,500 a year in sales but it only yielded €3,100 last year.

The strength needed to handle traffic makes them more expensive than conventional rooftop panels and, without the air that circulates around roofs, they often overheat. A 1km stretch of “photovoltaic highway” in China was abandoned in 2017 when it was stolen by thieves.

Wattway conceded that technological changes were needed. “Our system is not mature for inter-urban traffic,” said Etienne Gaudin, Wattway’s chief executive.

Wattway runs more than 40 similar solar roads but they are all smaller in scale than the stretch in Normandy.

Picture credit: Wikimedia

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