Trade tensions with China are especially sensitive at a time when the United States and other Western economies want to boost technology exports to revive economic growth and cut high unemployment.
The U.S. and China are two of the world's biggest markets for solar, wind and other renewable energy technology. Both governments are promoting their own suppliers in hopes of generating higher-paid technology jobs.
Sen. Ron Wyden, D-Ore., chairman of the Senate Finance Committee's subcommittee on trade, said the Commerce Department decision goes far beyond a dispute over solar panels.
"Free trade does not mean trade free from rules," Wyden said, calling the decision a boost for a rules-based global trading system. "A victory for that system is a victory for American workers and all others who don't need to cheat to compete," Wyden said.
In its ruling Thursday, Commerce also granted SolarWorld's request for a finding of "critical circumstances" to counter a recent flood of Chinese imports into the U.S. market ahead of the widely anticipated decision. As a result, preliminary dumping tariffs will be imposed retroactive to late February.
A final decision is expected in October.
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