The reasons for these requirements can be summarized as follows. Biomass with moisture contents below Miscanthus spp. are high-yielding perennial C 4 grasses, native to 200 to 250 g kg Ϫ1 fresh matter can be stored safely Asia, that are being investigated in Europe as potential biofuels. Production of economically viable solid biofuel must combine high without the danger of self ignition (Clausen, 1994) and biomass yields with good combustion qualities. Good biomass com-burns more efficiently while ash lowers the heating value bustion quality depends on minimizing moisture, ash, K, chloride, N, of the biomass and causes slagging of the boiler heat and S. To this end, field trials at five sites in Europe from Sweden exchangers (Hartmann et al., 1999). High levels of K to Portugal were planted with 15 different genotypes including M. ϫ are undesirable because it decreases the ash melting giganteus, M. sacchariflorus, M. sinensis, and newly bred M. sinensis point, but critical levels will depend on combustion techhybrids. Yield and combustion quality at an autumn and a late winter/ nique. Chloride can lead to corrosion through reaction early spring harvest were determined in the third year after planting with water to form HCl or with K to form gaseous when the stands had reached maturity. As expected, delaying the KCl, both of which are corrosive and reduce boiler life harvest by three to four months improved the combustion quality of (Baumbach et al., 1997). Furthermore, high chloride all genotypes by reducing ash (from 40 to 25 g kg Ϫ1 dry matter), K (from 9 to 4 g kg Ϫ1 dry matter), chloride (from 4 to 1 g kg Ϫ1 dry concentrations can lead to emissions of dioxine and matter), N (from 5 to 4 g kg Ϫ1 dry matter), and moisture (from furane (Siegle and Spliethoff, 1999). Nitrogen concen-564 to 291 g kg Ϫ1 fresh matter). However, the delayed harvest also trations in biofuels need to be as low as possible to decreased mean biomass yields from 17 to 14 t ha Ϫ1 . There is a strong minimize fertilizer off-takes and to reduce emissions interaction among yield, quality, and site growing conditions. Results of NO x during combustion. To avoid SO 2 emissions, show that in northern regions of Europe, M. sinensis hybrids can be biomass S concentrations also need to be as low as recommended for high yields (yielding up to 25 t ha Ϫ1 ), but M. sinensis possible. (nonhybrid) genotypes have higher combustion qualities. In mid-and To date, most research on Miscanthus sp. as an energy south Europe, M. ϫ giganteus (yielding up to 38 t ha Ϫ1 ) or specific crop has concentrated on maximizing the yield of a high-yielding M. sinensis hybrids (yielding up to 41 t ha Ϫ1 ) are more genotypes selected, there were four acquisitions of M. ϫ gigan-