This paper provides the results of the tests on bioenergy plants-topinambours and sunflowers, their cultivation and usage for fuels. Previous investigations show that stalks of topinambours, grown in fertile soil and fertilised, can reach up to 4 m height and give up to 15 t dry matter (D.M.) ha(-1) of the green mass, sunflowers-3m and 11 tD.M. ha(-1), respectively. Effective way to minimise the moisture of energy plants is to keep them harvested in the storage. The stems of the topinambours cut in autumn reaches 20% moisture content in 11 days, the sunflowers-in a month. Physical-mechanical characteristics of chopped stems-angles of fall and natural crumble, is important for construction of stores of chopped mass. These angles of large-stalked plants, chopped by forage combines E-281C and Krone-Big varied marginally: angle of fall-from 74 degrees to 82 degrees, angle of natural crumble-from 45 degrees to 47 degrees. There were investigations on main physical-mechanical characteristics of chopping quality of bioenergy plants. Chopping quality of topinambours and sunflowers, chopped by the stationary fodder chopper SPP-1 was sufficient high, and we recommend this chopper to chop the bioenergy plants. Experimental data of chopping quality of combines E-281C and Krone-Big show, that the amount of dust, which was large enough (8.6-12.5%) was affected by stalks were chopped with leafs during trials. According to the fineness requirements for fuel-chaff, stalks were chopped in good quality, despite large amount of dust. (c) 2008 Elsevier Ltd. All rights reserved.