A renewal of tax incentives for building and installing clean energy sources was stripped from the recently signed energy bill, putting wind and solar boosters just a wee bit on edge. Current federal tax credits for renewable energy will expire at the end of 2008; Rhone Resch of the Solar Energy Industries Association predicts that U.S. solar installations, which jumped 80 percent in 2007, will “start to drop off in the second quarter of 2008 if [tax incentives] are not extended.” But all is not lost: Leaders in both chambers of Congress have promised to revisit the tax-credit issue in the new year.