Careful selection of crop species, amoung other aspects, is very helpful in enhancing energy production by way of increased biomass yields from agricultural land. A wide range of C-3 and C-4 plant species has been introduced and investigated for their environmental and climatic impact. The results indicate already that some perennial C-4 crop species posses high yield potential, lower erosion-index, better CO2 reduction rates and need less fertilizer, water and chemicals.