Then French environment minister Segolene Royal said in December 2016 that the country would develop a solar panel road network across the country despite criticism of its high cost

French local authorities said Wednesday that a high-profile "solar highway" experiment in Normandy had failed, but vowed to try again with new panels on a shorter stretch of road.

"As time went on, we realized that on an economic and financial level, in terms of producing , it was a failure," said Alain Pelleray, a senior regional official in the Orne department.

From the time the one-kilometre-long (half-mile) was inaugurated with great fanfare in December 2016 until March this year, the experimental route had produced 229 megawatt hours (MWh) of electricity, far less than an initial forecast of 642 MWh, he added.

Instead of bringing in the expected 22,000 euros ($24,500) by selling the electricity generated to the state-owned power company EDF, the department had only received 8,000 euros, the official said.

The road in Tourouvre, population 1,500, had been financed by five million euros in state aid, and the environment minister at the time, Segolene Royal, had announced a four-year plan for a national roll-out.

But problems cropped up with and rapid wear on the road, forcing officials to curb the speed limit on the to 70 kilometres per hour (45 mph).

The panels will now be taken up and replaced new-generation ones on a 400-metre (440-yard) stretch, Pelleray said.

All was not lost, he added, since the project had already attracted international interest.

"We have no regrets, the department did not spend anything on this and we are talking about applied research. In terms of renown, we hit the jackpot. We've had visits by Korean and Chinese tourists and industrialists."