高速路上的免費電力?中國試鋪太陽能公路

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. Only a single, unreinforced guardrail stood between the traffic and a ravine.

中國濟南——一個霧霾天的下午，運輸木材的大貨車和油罐車沿高速公路隆隆行駛，從一處山腳下的彎道呼嘯而過。車流和一旁的山溝之間，只隔着一道沒有加固的護欄。

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.

在任何天氣情況下這段路都不好開。但專家們正在監測的是路面的一個具體部位：高速公路的彎道上鋪設了太陽能電池板。

“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 sector, and on the driving experience, too.

“如果能通過這個路段的測試，就能適應各種條件，”山東光實能源有限公司董事長李武說，鋪在路面上的那些覆蓋塑料表層的太陽能板，就是這家公司生產的。如果他的產品運行良好，將對可再生能源領域產生重大影響，也會極大地影響駕駛體驗。

The experiment is the latest sign of China’s desire to innovate in, and dominate, the increasingly lucrative 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.

可再生能源市場越來越有利可圖，在戰略上也日益重要，中國渴望該領域的創新和主導地位，高速公路上的試驗就是這種渴望的又一表現。中國已經生產了全球銷售的太陽能電池板的四分之三，其風力發電機制造業也是世界最大的。

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 conserve 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.

這種用改裝太陽能電池板取代瀝青鋪在路面的太陽能公路，潛在吸引力是顯而易見的。在高速公路和街道上發電，而不是鋪滿太陽能電池板的田野和沙漠，可以節約大量土地。在中國這個人口衆多、能源需求迅速增長的國家，這些優勢尤爲重要。

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 essentially free, because roads are needed anyway. Roads must be resurfaced every few years at great cost, so the installation of durable solar panels could reduce the price of maintenance.

因爲城市內部和周邊都有路，路上發的電能夠就近使用。也就是說幾乎不會有傳輸損耗，不像那些地處偏遠的太陽能發電項目。而且用地基本免費，因爲公路反正總是需要的。公路每隔幾年必須重鋪路面，花費不菲，安裝耐用的太陽能電池板也許還能降低公路維護成本。

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.

太陽能公路也可能改變駕駛體驗。電熱條可以融化落在路面的雪。嵌在電池板表面的發光二極管可以顯示發光標識，指導駕駛員駛下出口，提醒他們注意道路施工和其他交通危險。

Now, such roads are finally becoming viable. 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 wirelessly recharge electric cars running on them, emulating a recent American experiment.

現在這種公路終於切實可行了。近年來太陽能電池板的價格急劇下跌——主要歸功於中國電池板的產量飆升，一塊電池板的價錢僅爲十年前的十分之一。中國的築路企業甚至希望趕超美國最近進行的一項實驗，設計出一種太陽能公路，能給路上行駛的電動汽車無線充電。

China’s leaders in solar road development are Pavenergy and Qilu Transportation. 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.

光實能源和齊魯交通發展集團是中國太陽能公路發展的領先者。兩家公司正在山東濟南進行合作，光實能源爲齊魯交通這家大型國有高速公路建設及管理公司生產太陽能電池板。

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. 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.

上海同濟大學的交通運輸工程學教授張宏超表示，太陽能電池板由類似塑料的複雜聚合物製成，表面摩擦力比傳統路面略高。參與了光實能源電池板路面開發的張宏超說，製造過程中可以按需要調整表面摩擦力，確保這種路面的輪胎抓地力水平與瀝青路面相同。

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 proximity to an electricity substation, ensuring that it would be connected to the grid. 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.

進行試驗的這條太陽能公路位於山腳下的一處長彎道，這並非光實公司的首選地點。選址於此是因爲這裏靠近一個變電站，確保了發電能夠入網。中國正在全國各地新建太陽能和風能發電站，速度太快，以至一些遠離變電站的發電項目有時需要推遲數年才能入網。

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.

光實能源和齊魯交通主要的西方競爭對手是科拉(Colas)，這家法國公路建設巨頭已經開發了25處實驗性的太陽能公路及停車場，主要在法國，在加拿大、日本和美國也有。科拉最大的太陽能項目是一年半前在諾曼底投入使用的一條鄉村公路，表面積只有濟南新建太陽能公路的一半。出於安全顧慮，科拉一直不願將太陽能電池板裝在與中國這條公路類似的高速路上；張宏超說這些電池板非常安全。

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

不過，一連串的難題表明太陽能公路距離大範圍鋪設還很遙遠。

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

首先，太陽能公路將陽光轉換爲電力的效率低於屋頂太陽能電池板。公路電池板是水平放置的，而且間歇性地被車輛遮擋，而屋頂電池板向太陽傾斜，因此前者生產的電能只有後者的大約一半。

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.

太陽能公路也比瀝青路貴。每十年重新鋪設和修復瀝青路面，每平方米大約要花120美元。相比之下，光實能源和科拉期望在大規模生產時能把太陽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.

張宏超說，高速公路上的電池板的更換，可能不像瀝青路面那麼頻繁。路上的電池板每平方米每年還能生產價值約15美元的電力。因此與瀝青相比，電池板用上大約15年就能夠抵銷成本。

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.

但這些電池板能否承受連續十幾年、每年幾百萬次的車輪碾壓，或者是否會被偷走，就不那麼好說了。

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 espionage.

濟南這條公路上的電池板在去年12月下旬安裝完後不到一週，就不見了幾個平方英尺，人們擔心這是小偷甚至產業間諜乾的。

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

面對治安不力的指責，當地警方表示，電池板應該是被重型卡車壓成碎粒，碾得四散了。光實能源對此未予置評。

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

在美國，鋪設太陽能公路就是一個更棘手的問題了。

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 underneath than roads elsewhere, said Kara M. Kockelman, a transportation engineering professor at the University of Texas.

德克薩斯州大學交通工程教授卡拉·M·科克曼(Kara M. Kockelman)說，除了部分橋樑和州際高速公路的某些路段外，美國公路往往用大量瀝青鋪就，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 silicon of solar cells, the panels’ electricity-generating component, can withstand being mashed by many tons of weight. But the nearly paper-thin cells snap when bent, 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.)

瀝青的問題是在卡車的重壓下會輕微變形。太陽能電池的藍色硅晶片，也就是電池板的發電部件，能夠承受數噸的重壓。但一遇彎折，紙一般薄的硅晶片就會像薄薄的糖片一樣折斷。（在中國，高速公路鋪有很厚的混凝土路基，這就不是太大的問題。）

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.

不過這裏的企業高管們是滿懷希望的。他們說技術已然完備，即使美國高速公路建設的情況複雜，他們也並不擔心。

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

“如果條件允許，”齊魯交通發展集團的董事長徐春福說，“我還想到美國建一條光伏路。”