From the NY Times:
Reuters has more and notes that the solar energy industy is trying to get the decision reversed:
I wonder if this will lead to a WTO complaint at some point. There have been a few complaints over the years related to changes in tariff classification, including one going on right now against the EC on information technology products. Such complaints can be difficult, though, in part because there are no explicit rules on classification (unlike customs valuation). Instead, the GATT Article II provisions making the schedules of concessions operative are applied. (For DSC subscribers, we discuss this a bit in a DSC blog post here).
It probably makes sense to press the issue through domestic channels first, as the industry is doing. If they do not have any luck there, they may turn to the WTO. The key will be the precise language of the U.S. WTO Schedule in relation to the product at issue. I have not looked at this, so I don't have a good sense of such a claim's chance of success, but I assume the industry's trade lawyers have been checking it out.
ADDED: I think this is the ruling referenced in the article: