A side note -- the study looks at the merits and shortcomings of using tax policy as a way to curb greenhouse gas emissions. It notes that many analysts see tax credits as “inefficient tools” to promote reduced emissions.
From the study:
For example, conserving home heating oil by installing solar heating systems is encouraged by a tax credit, but turning thermostats down and wearing sweaters is not, even though doing so could achieve substantial reductions in GHG emissions at a lower cost. Tax preferences that are intended to encourage consumers and producers of electricity to choose technologies that reduce emissions vary widely in the amount of GHG emissions curtailed per tax dollar forgone. According to one calculation, the subsidy per ton of greenhouse gases not emitted can vary by about 50 percent from the same tax provision, depending on whether it is used for wind or geothermal technology. Most analysts believe that better results might come from increasing the price of GHG emissions because market forces tend to equalize the cost of reducing GHG emissions as consumers and producers respond to price signals. Despite their limitations, tax credits and deductions have helped encourage investment in renewable sources of energy.