In honor of Labor Day in the U.S., here's an update on where clean energy jobs are popping up. More than 38,000 U.S. jobs will result from five dozen "clean" energy and transportation projects announced from April-June of this year, spanning energy generation, manufacturing, transmission/smart grid, energy efficiency, and public transportation, according to a report by nonprofit group Environmental Entrepreneurs (E2). That's up slightly from the same period a year ago (37,400), and triple the job announcements from the first three months of this year (12,000).