In Austria it is planned to use Miscanthus sinensis 'Giganteus' as a renewable energy source. The influence of site, age of crop and time of harvest on yield, water content, nitrogen content and quality was investigated. In the first year the yield was 0.7 to 2 t dry matter ha-1, in the second year 7.9 to 15.5 t ha-1 and in the third year 17.4 to 24.5 t ha-1. In February of the first year the water content was 40 to 50%, in the second year 34 to 49% and in the third year 24 to 38%. Sufficient precipitation (about 800 mm) in mild climates is required for high yields. On sites with more rain the water content of the plants was higher. Water and nitrogen content decreased significantly during the six week period from January to the end of February. In February of the first year the nitrogen content was 7.8 to 16.6 g kg-1 dry matter, in the second year 3.7 to 6.2 g kg-1 and in the third year 2.6 to 7.5 g kg-1. The calorific value was as high as that of firewood (18 to 19 MJ kg-1). The ash content exceeded firewood but was lower than that of straw. By the third year of cultivation 60 to 150 kg N ha-1, 100 to 200 kg K2O ha-1, 10 to 35 kg P2O5 ha-1, 10 to 25 kg MgO ha-1 and 20 to 35 kg CaO ha-1 had to be taken up by the harvest at the end of February.