The Senate version of the stimulus bill passed today. Now it’s on to conference where legislators will try to work out differences between it and the House version of the bill.

One of the most significant differences between the bills, with regard to energy, has to do with provisions related to renewable energy tax credits. Renewable energy companies and those companies that finance them haven’t been able to take advantage of tax credits lately, since they haven’t been making enough money to have to pay any taxes. Renewable energy companies been suffering as a result, seeing financing dry up and projects stalled.

The House version of the bill contains a provision that would allow companies to get the money from those tax credits anyway–the money would take the form of a government grant. An early version of the Senate bill included a similar provision: a “carry-back” provision that allowed companies to take credits against taxes owed in previous years. But it was stripped from the final version.

There’s a lot at stake here. Many renewable energy projects simply won’t go forward without some sort of access to tax credits. The current tough times for the fledgling renewable energy industry could continue, but if the tax credits are made available, that could free up funding for new projects.

The Senate finance committee has a run-down of the other differences between the bills.