Although dwarfted by the largesse given to the fossil fuel industry, solar energy got a significant boost in the recently passed energy bill.
The law both increases tax credits for commercial solar installations and offers individual home owners a credit for the first time since Jimmy Carter.
Under the new law, businesses that buy solar equipment can claim a federal tax credit equal to 30% of the equipment's cost, with no dollar limit on how big the credit can be. (In 2008, the credit reverts back to today's 10% of cost level.)
Home owners get a more limited credit. They can put in a photovoltaic system (those are the roof panels that take in energy from the sun and turn it into electricity) and/or a solar-powered hot water system (for hot water heaters, radiant floors or radiators), and get a federal tax credit worth 30% of the systems' cost, up to a credit of $2,000 per system. There are a couple of catches. The heating system can't be for a pool or hot tub. And the federal credit applies to the net system cost after any state incentives.
The bad news--the credits are only authorized for two years.