The CLEAN ENERGY PATENT GROWTH INDEX (CEPGI), published quarterly by the
Cleantech Group at Heslin Rothenberg Farley
& Mesiti P.C. provides an indication of the trend of innovative activity in the Clean Energy sector from 2002
to the present. Results from the first quarter of 2013 reveal the CEPGI to have a value of 738 granted U.S. patents which is down 45
relative to the fourth quarter total of 783, but is up 44 over the quarter from one year prior. GM was granted the highest number of
clean energy patents for the first quarter.