Exhibit 10.21 THIRD SUPPLEMENTAL AGREEMENT FOR THE SALE OF ELECTRIC ENERGY FROM THE SCRUBGRASS GENERATION PLANT ---------------------------------------- This THIRD SUPPLEMENTAL AGREEMENT, made and entered into this 13th day of August, 1990 by and...Third Supplemental Agreement for the Sale of Electric Energy • April 15th, 1997 • Environmental Power Corp • Cogeneration services & small power producers • Pennsylvania
