Federal tax credits for green energy spending largely benefit the wealthy, according to a new working paper published by the National Bureau of Economic Research.

The wealthiest 20 percent of Americans, who earn over $75,000 a year, receive 60 percent of the tax credits. The poorest 60 percent of Americans received only 10 percent of the tax credits. The tax credits encourage “clean energy” investments, such as solar panels, home weatherization, and hybrid or electric cars.