INAN, China — On a smoggy afternoon, huge log carriers and oil tankers¹ thundered down a highway and hurtled around a curve at the bottom of a hill. Only a single, unreinforced guardrail stood between the traffic and a ravine.

中国济南——一个雾霾天的下午，运输木材的大货车和油罐车沿高速公路隆隆行驶，从一处山脚下的弯道呼啸而过。车流和一旁的山沟之间，只隔着一道没有加固的护栏。

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.

在任何天气情况下这段路都不好开。但专家们正在监测的是路面的一个具体部位：高速公路的弯道上铺设了太阳能电池板。

“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. If his product fares well, it could have a major impact on the renewable energy sector², and on the driving experience, too.

“如果能通过这个路段的测试，就能适应各种条件，”山东光实能源有限公司董事长李武说，铺在路面上的那些覆盖塑料表层的太阳能板，就是这家公司生产的。如果他的产品运行良好，将对可再生能源领域产生重大影响，也会极大地影响驾驶体验。

The experiment is the latest sign of China’s desire to innovate³ in, and dominate, the increasingly lucrative⁴ and strategically important market for renewable energy. The country already produces three-quarters of the solar panels sold globally, and its wind-turbine manufacturing industry is also among the world’s largest.

可再生能源市场越来越有利可图，在战略上也日益重要，中国渴望该领域的创新和主导地位，高速公路上的试验就是这种渴望的又一表现。中国已经生产了全球销售的太阳能电池板的四分之三，其风力发电机制造业也是世界最大的。

The potential appeal of solar roads — modified solar panels that are installed in place of asphalt — is clear. Generating electricity from highways and streets, rather than in fields and deserts packed with solar panels, could conserve⁵ a lot of land. Those advantages are particularly important in a place like China, a heavily populated country where demand for energy has risen rapidly.

这种用改装太阳能电池板取代沥青铺在路面的太阳能公路，潜在吸引力是显而易见的。在高速公路和街道上发电，而不是铺满太阳能电池板的田野和沙漠，可以节约大量土地。在中国这个人口众多、能源需求迅速增长的国家，这些优势尤为重要。

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, as can happen with projects in outlying locations. And the land is essentially⁶ free, because roads are needed anyway. Roads must be resurfaced every few years at great cost, so the installation of durable⁷ solar panels could reduce the price of maintenance.

因为城市内部和周边都有路，路上发的电能够就近使用。也就是说几乎不会有传输损耗，不像那些地处偏远的太阳能发电项目。而且用地基本免费，因为公路反正总是需要的。公路每隔几年必须重铺路面，花费不菲，安装耐用的太阳能电池板也许还能降低公路维护成本。

Solar roads could also change the driving experience. Electric heating strips can melt snow that falls on them. Light-emitting diodes embedded⁸ in the surface can provide illuminated⁹ signage to direct drivers to exits and alert them to construction and other traffic hazards.

太阳能公路也可能改变驾驶体验。电热条可以融化落在路面的雪。嵌在电池板表面的发光二极管可以显示发光标识，指导驾驶员驶下出口，提醒他们注意道路施工和其他交通危险。

Now, such roads are finally becoming viable¹⁰. Prices have fallen drastically in recent years — thanks in large part to soaring Chinese production, a solar panel costs a tenth of what it did a decade ago. Road builders in China even want to design solar roads that can wirelessly¹¹ recharge electric cars running on them, emulating¹² a recent American experiment.

现在这种公路终于切实可行了。近年来太阳能电池板的价格急剧下跌——主要归功于中国电池板的产量飙升，一块电池板的价钱仅为十年前的十分之一。中国的筑路企业甚至希望赶超美国最近进行的一项实验，设计出一种太阳能公路，能给路上行驶的电动汽车无线充电。

China’s leaders in solar road development are Pavenergy and Qilu Transportation¹³. The two companies are working together here in Jinan, in Shandong Province, with Pavenergy making panels for Qilu, a large, state-owned highway construction and management company that operates the highway.

光实能源和齐鲁交通发展集团是中国太阳能公路发展的领先者。两家公司正在山东济南进行合作，光实能源为齐鲁交通这家大型国有高速公路建设及管理公司生产太阳能电池板。

The surface of these panels, made of a complex polymer that resembles plastic, has slightly more friction¹⁴ than a conventional road surface, according to Zhang Hongchao, an engineering professor at Tongji University in Shanghai. Professor Zhang, who helped develop Pavenergy’s road surface, said that the friction could be adjusted as needed during the manufacturing process to ensure a level of tire grip equal to that of asphalt.

上海同济大学的交通运输工程学教授张宏超表示，太阳能电池板由类似塑料的复杂聚合物制成，表面摩擦力比传统路面略高。参与了光实能源电池板路面开发的张宏超说，制造过程中可以按需要调整表面摩擦力，确保这种路面的轮胎抓地力水平与沥青路面相同。

The location of the solar road here, on a long curve at the bottom of a hill, was not Pavenergy’s first choice. The site was chosen because of its proximity¹⁵ to an electricity substation, ensuring that it would be connected to the grid¹⁶. China is adding solar and wind energy sites so fast across the country that power generation projects farther from substations sometimes face delays of years in getting connected.

进行试验的这条太阳能公路位于山脚下的一处长弯道，这并非光实公司的首选地点。选址于此是因为这里靠近一个变电站，确保了发电能够入网。中国正在全国各地新建太阳能和风能发电站，速度太快，以至一些远离变电站的发电项目有时需要推迟数年才能入网。

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, mostly in France but also in Canada, Japan and the United States. The biggest of Colas’s solar sites, a country road in Normandy that opened a year and a half ago, has only half the surface area of the new solar highway in Jinan. Colas has been leery of putting solar panels on high-speed roads like the Chinese highway because of safety concerns; Professor Zhang said the panels were completely safe.

光实能源和齐鲁交通主要的西方竞争对手是科拉(Colas)，这家法国公路建设巨头已经开发了25处实验性的太阳能公路及停车场，主要在法国，在加拿大、日本和美国也有。科拉最大的太阳能项目是一年半前在诺曼底投入使用的一条乡村公路，表面积只有济南新建太阳能公路的一半。出于安全顾虑，科拉一直不愿将太阳能电池板装在与中国这条公路类似的高速路上；张宏超说这些电池板非常安全。

Still, a litany of outstanding challenges means the wide deployment¹⁷ of solar roads is a long way off.

不过，一连串的难题表明太阳能公路距离大范围铺设还很遥远。

For one, they are less efficient than rooftop solar panels at converting the sun’s light into electricity. They lie flat, and are intermittently¹⁸ covered by vehicles, so solar panels on a road produce only around half the power that rooftop ones tilted¹⁹ toward the sun do.

首先，太阳能公路将阳光转换为电力的效率低于屋顶太阳能电池板。公路电池板是水平放置的，而且间歇性地被车辆遮挡，而屋顶电池板向太阳倾斜，因此前者生产的电能只有后者的大约一半。

Solar roads are also more expensive than asphalt. It costs about $120 a square meter, or about $11 a square foot, 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 with mass production.

太阳能公路也比沥青路贵。每十年重新铺设和修复沥青路面，每平方米大约要花120美元。相比之下，光实能源和科拉期望在大规模生产时能把太阳能公路的成本拉低到每平方米310到460美元。

Panels on a highway would likely 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, compared with asphalt, over about 15 years.

张宏超说，高速公路上的电池板的更换，可能不像沥青路面那么频繁。路上的电池板每平方米每年还能生产价值约15美元的电力。因此与沥青相比，电池板用上大约15年就能够抵销成本。

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.

但这些电池板能否承受连续十几年、每年几百万次的车轮碾压，或者是否会被偷走，就不那么好说了。

Several square feet of solar panels disappeared less than a week after they were installed here in late December, raising worries of theft or even industrial espionage²⁰.

济南这条公路上的电池板在去年12月下旬安装完后不到一周，就不见了几个平方英尺，人们担心这是小偷甚至产业间谍干的。

Local police officers, facing criticism for not providing better security, said that the panels must have been crushed into tiny pieces and scattered²¹ by heavy trucks. Pavenergy declined to comment.

面对治安不力的指责，当地警方表示，电池板应该是被重型卡车压成碎粒，碾得四散了。光实能源对此未予置评。

In the United States, installing solar roads is more complicated.

在美国，铺设太阳能公路就是一个更棘手的问题了。

With the exception of some bridges and sections of interstate highways, American roads tend to be built with a lot of asphalt, but with less concrete underneath²² than roads elsewhere, said Kara M. Kockelman, a transportation engineering professor at the University of Texas.

德克萨斯州大学交通工程教授卡拉·M·科克曼(Kara M. Kockelman)说，除了部分桥梁和州际高速公路的某些路段外，美国公路往往用大量沥青铺就，但路面下的混凝土比其他地方的公路用得少。

The problem with asphalt is that it compresses slightly under the weight of trucks. The blue silicon²³ of solar cells, the panels’ electricity-generating component²⁴, can withstand being mashed²⁵ by many tons of weight. But the nearly paper-thin cells snap when bent²⁶, like a thin sheet of sugar. (This is not as much of an issue in China, where highways are built with very thick concrete bases.)

沥青的问题是在卡车的重压下会轻微变形。太阳能电池的蓝色硅晶片，也就是电池板的发电部件，能够承受数吨的重压。但一遇弯折，纸一般薄的硅晶片就会像薄薄的糖片一样折断。（在中国，高速公路铺有很厚的混凝土路基，这就不是太大的问题。）

Still, executives here are hopeful. They say that the technology is ready and that they are not concerned even by the complications of American highway construction.

不过这里的企业高管们是满怀希望的。他们说技术已然完备，即使美国高速公路建设的情况复杂，他们也并不担心。

“If conditions permit,” Xu Chunfu, Qilu’s chairman, said, “I would like to build a solar road in the United States.”

“如果条件允许，”齐鲁交通发展集团的董事长徐春福说，“我还想到美国建一条光伏路。”