U.S. companies held 1.6 billion dollars of trade surplus in clean energy trade with China in 2011, said a report released on Wednesday by the Pew Charitable Trust.

The report, Advantage America: The U.S.-China Clean Energy Trade Relationship in 2011, found that the United States and China traded more than 8.5 billion dollars worth of clean energy goods and services in 2011, the latest year for which data are available.

The report prepared by the independent non-profit organization concluded that America's clean energy trade strength is derived from innovation and entrepreneurship. While China's clean energy industry has an advantage in large-scale manufacturing and high- volume assembly of certain clean energy products.

However, tensions have been highlighted in recent years by fiercely competitive market conditions affecting companies in both countries, as well as several high-profile trade cases.

In solar energy, the largest component of clean energy trade for both countries, firms traded more than 6.5 billion dollars of products and services in 2011. Chinese firms sell large quantities of finished solar cells and modules to the United States, from whom China then buy high value-added goods and services, such as polysilicon and wafers, as well as high-tech materials and equipment needed in solar manufacturing. On a net basis, the U.S. enjoyed a 913-million-dollar surplus in the solar sector.

But the U.S. Commerce Department has levied steep duties on crystalline silicon photovoltaic cells and modules from China since last year, saying that their dumping margins ranges from 18. 32 percent to 249.96 percent and they received countervailable subsidies of 14.78 percent to 15.97 percent. The decision overlooked the globalized value chain, of which the U.S. has been taking advantage.

In wind energy, more than 923 million dollars of goods and services were exchanged between the two countries in 2011. The U.S. wind industry excels in sales of relatively high-margin specialty materials (fiberglass) and sensitive electronic and other control system. While China's largest sales were in turbine towers and rotors. Overall, U.S. firms held a net trade surplus of over 146 million dollars.

As with solar, the U.S. Commerce has also punished import of utility scale wind towers from China since last year, saying that their dumping margins ranges from 44.99 percent to 70.63 percent and they received countervailable subsidies of 21. 86 percent to 34.81 percent.

Besides, the two countries also traded energy smart technologies including smart meters, light emitting diodes (LEDs), advanced lithium-ion batteries, and electric vehicles. More than 1. 1 billion dollars of these products flowed in 2011, with the U.S. held a net trade surplus of 571 million dollars in the sector.