To date, Miscanthus biomass has been mainly used to generate renewable heat, electricity and combined heat and power. Its use in biofuel production is under investigation in several countries, as is its potential as a component in bio-based concrete materials and bio-based plastic composites (Section 4.4.1, Past and Current Projects). The composition of Miscanthus biomass must be optimized to suit to each end use (Table 4.1). However, the biomass composition of Miscanthus species varies widely and it is critical that new Miscanthus varieties are developed to provide consistent biomass compositions suited to specific industrial processes.

For biomass combustion, it is essential that the moisture, ash and mineral content of the biomass are minimized, as these reduce process efficiency [1, 43]. M. sinensis genotypes have a higher combustion quality because they contain lower contents of chlorine and potassium than M. x giganteus [55]. Delaying harvest from autumn until late winter can also improve the combustion quality of Miscanthus biomass because moisture, ash, potas­sium, chlorine and nitrogen contents are lowest at this time [43, 56]. Ranges of the main biomass components are illustrated for M. x giganteus (Table 4.1). The differing mineral and ash content of Miscanthus leaves and stems between clones or harvest dates provides an opportunity to manipulate biomass composition better suited to combustion [1, 57, 58].

Efficient biofuel production requires high levels of cellulose and hemicellulose and low lignin content. From biomass components, the cellulose shows the highest content at 41­52% of biomass dry matter (Figure 4.5), the hemicellulose displays 24-34% and the lignin varies from 8.8 to 12.6% [40, 47, 53, 56, 59,60]. Cellulose, hemicellulose and lignin

contents tend to increase between autumn and late winter in Miscanthus species. Between species, M. x giganteus and M. sacchariflorus species globally have higher cellulose and lignin contents and lower hemicellulose content than M. sinensis species (Figure 4.5). One exception to this is the work by Lygin et al. [61], who found that the M. sinensis “Grosse Fontaine” clone had higher cellulose content than M. x giganteus.

In summary, it would appear there is sufficient genetic variation in biomass productivity and biomass composition to breed Miscanthus varieties well suited to bioenergy use.