China has opened a 1-kilometer long solar road in Jinan, the capitol of Shandong province south of Beijing. The two-lane road covers 5,875 square meters and can generate up to 1 million kilowatt-hours of power annually — enough to power 800 Chinese homes, according to XinhuaNet. The electricity will be used to run street lights, billboards, surveillance cameras, and toll collection plazas. It will also be used to heat the road surface to keep it clear of snow. Any excess will be fed back into the local utility grid.
The surface of the road is made of transparent concrete which can withstand 10 times more pressure than regular concrete, according to Slate. Beneath the concrete are solar panels that convert sunlight to electricity. Under the solar panels is an insulating layer designed to protect them from excessive heat or cold.
“The project will save the space for building solar farms and shorten the transmission distance,” said Xu Chunfu, chairman of Qilu Transportation Development Group, the project developer. He claims the Chinese solar road cost half as much as similar roads in other countries. France, for one, is experimenting with solar roads as well.
But Slate claims the Chinese road cost $458 per square meter — roughly 90 times the cost of a traditional asphalt road. Figures lie and liars figure, so the jury is still out on whether China’s electric highway is cost-effective, but $458 per square meter does seem mighty expensive. “With the development of solar power in China, the cost can be further reduced,” Xu says. In crowded cities (China has more than 120 cities with a population of one million of more), there is not always room for solar panels, so finding alternative locations such as roads and bodies of water is becoming more common.
Still, one wonders whether concrete transparent enough to let sunlight through will be slick when wet, perhaps leading to more traffic accidents. Also, laying solar panels flat decreases their efficiency somewhat. And how does one replace a defective solar panel if it is encased under a layer of concrete? Only experience with solar roads will tell whether they are worth the investment or just an expensive boondoggle.