JINAN, China — On a smoggy afternoon, huge log carriers and oil tankers thundered down a highway and hurtled around a curve at the bottom of a hill. The route could make for tough driving under any conditions. But experts are watching it for one feature in particular: The highway curve is paved with solar panels.

«If it can pass this test, it can fit all conditions,» said Li Wu, the chairman of Shandong Pavenergy, the company that made the plastic-covered solar panels that carpet the road.

The experiment is the latest sign of China’s desire to dominate the increasingly important market for renewable energy. The country already produces three-quarters of the solar panels sold globally.

The appeal of solar roads — modified solar panels that are installed in place of asphalt — is clear. Generating electricity from streets, rather than in fields and deserts packed with solar panels, could conserve a lot of land. Because roads run through and around cities, the electricity could be used practically next door to where it is generated. That means virtually no power would be lost in transmission. And the land is essentially free, because roads are needed anyway.

Solar roads could also change the driving experience. Electric heating strips can melt snow that falls on them. Light-emitting diodes embedded in the surface can provide illuminated signage to direct drivers to exits and alert them to construction and other traffic hazards. Road builders in China even want to design solar roads that can wirelessly recharge electric cars running on them.

China’s leaders in solar road development are Pavenergy and Qilu Transportation. The two are working together here in Jinan, with Pavenergy making panels for Qilu, a large, state-owned company that operates the highway.

The surface of these panels, made of a complex polymer that resembles plastic, has slightly more friction than a conventional road surface, according to Zhang Hongchao, an engineering professor at Tongji University in Shanghai who helped develop it.

The location of the solar road here, on a long curve at the bottom of a hill, was not Pavenergy’s first choice. It was chosen because of its proximity to an electricity substation.

The main Western rival to Pavenergy and Qilu is Colas, a French road-building giant that has developed 25 experimental solar roads and parking lots, in France, Canada, Japan and the United States. The biggest of Colas’s solar sites, a country road in Normandy, has only half the surface area of the new solar highway in Jinan.

Still, challenges mean the wide deployment of solar roads is a long way off. Solar panels on a road lie flat, and are intermittently covered by vehicles, so they produce only around half the power that rooftop ones tilted toward the sun do. Solar roads are also more expensive than asphalt. It costs about $120 a square meter to resurface and repair an asphalt road each decade. By comparison, Pavenergy and Colas hope to be able to bring the cost of a solar road to $310 to $460 a square meter.

But panels on a highway would probably need to be replaced less often than asphalt, Professor Zhang said. And a solar road can produce about $15 a year worth of electricity from each square meter of solar panels. So it could roughly pay for itself in 15 years. Less clear is whether the panels would be able to take the pounding of millions of tires each year for more than a decade, or whether they might be stolen.

And in the United States, installing solar roads is more complicated. American roads tend to be built with a lot of asphalt, but with less concrete underneath than roads elsewhere, said Kara M. Kockelman, a transportation engineering professor at the University of Texas. Asphalt compresses slightly under the weight of trucks. The blue silicon of solar cells, the panels’ electricity-generating component, can withstand many tons of weight. But the nearly paper-thin cells snap when bent.

Still, executives here say that the technology is ready and that they are not concerned. «If conditions permit,» Xu Chunfu, Qilu’s chairman, said, «I would like to build a solar road in the United States.»

An effort that could conserve land and energy.

© 2018 The New York Times