This paper estimates the efficiency of the power generation sector in the USA states by using Window Data Envelopment Analysis (W-DEA). We integrate radial and non-radial efficiency measurements in DEA using the hybrid measure while we extend the proposed model by considering inputs and good and bad outputs as separable and non separable. Then in the second stage analysis we perform various econometric techniques (parametric and non parametric) in order to model the relationship between the calculated environmental efficiencies and economic growth in attaining sustainability.
