Reuters: Still reeling from disappointing UN climate talks in Copenhagen in December, clean energy project developers were dealt another blow this week when U.S. Democrats lost their Senate supermajority, potentially killing a federal cap-and-trade scheme for years to come. Although the passage of a U.S. bill to cap greenhouse gas emissions in 2010 was far from certain, the election of a Republican in Massachusetts to the Senate on Tuesday derailed any momentum President Obama had following …