Some of the biggest solar companies in the United States, including First Solar, SolarCity and SunPower, have been stockpiling oil and natural gas products in part to feed their power-plant installation businesses, reported Bloomberg News in March.
But they also rely on a key supplier for those goods: China’s Tianma Petrochemical Group.
The Tianma division of China’s largest petrochemical company is among dozens that are quietly supplying oil to fuel the plants of roughly a dozen U.S. solar-power companies over the past year, according to documents reviewed by Bloomberg.
It is a system that has stoked criticism in Washington over mounting evidence that China is paying workers to pollute the environment and labor to build the high-profile domestic solar installations that have attracted $93 billion in private and public capital.
At the same time, Tianma, which has an office in Sacramento, has been buying a growing quantity of products from Trina Solar, one of the biggest U.S. solar manufacturers, according to the documents.
SunPower is one of two solar panel manufacturers currently producing 70 percent of their equipment in China, helping the country collect about $17.6 billion in annual solar-panel exports, according to BNEF, a research firm.
The importation of Chinese solar panels, clean coal and other energy sources to U.S. plants is expected to rise tenfold by 2025, BNEF predicted.