Development of a multi-criteria decision making model for evaluating the energy potential of Miscanthus germplasms for bioenergy production

Abstract

Biomass is the bioenergy carrier and can be converted to solid, liquid and gaseous fuels. Miscanthus, a plant type with high biomass yield potential, is a promising feedstock source for bioenergy production. However, the current expansion of miscanthus (Miscanthus spp.) production is constrained by a shortage of commercial varieties, especially those suitable for different energy usages and cultivation under adverse environmental conditions. Therefore, breeding or selecting high-biomass-yielding, high quality and stress tolerant miscanthus varieties is essential for the extension of miscanthus for bioenergy production. To effectively select elite germplasms and breed new varieties of miscanthus, it is necessary to establish a scientific evaluation method for analysing their energy potential. In this study, a multi-criteria decision making (MCDM) model was designed to evaluate the potential of miscanthus germplasms as feedstock in four energy usages including combustion for power generation (CPG), pyrolysis for bio-oil production (PBP), fermentation for ethanol production (FEP) and fermentation for biogas production (FBP). The MCDM model was constructed based on 11 sub-criteria indices, which were grouped into agronomic-related and quality-related criteria indices. The agronomic-related criteria indices include dry matter yield, canopy height, stem diameter, tiller number and base diameter/canopy diameter ratio. The quality-related criteria indices include the leaf/stem ratio, moisture content, ash content, cellulose content, hemicellulose content and lignin content. Thirty-eight representative germplasms of miscanthus were evaluated. The MCDM analysis results showed that Miscanthus lutarioriparius (especially the XiangNanDi no. 1 variety) and Miscanthus floridulus (especially A0521) are the best species for CPG/PBP and FEP/FBP, respectively. These results are superior to those calculated by the traditional energy potential assessment method, which showed that Miscanthus floridulus was the most suitable species for CPG, FEP and FBP, especially A0521 and D0624. Moreover, the analysis also indicated that D0505 (M. floridulus) can be used as a suitable parent together with XiangNanDi no. 1 to breed new varieties for CPG and PBP; XiangNanDi no. 1 can be used as an alternative parent for breeding to improve A0521 for use in FEP and FBP.