Assessing the bioenergy potential of grassland biomass from conservation areas in England

Abstract

Bioenergy may be one of the ecosystem services of the future for grasslands managed for conservation as the concept of bio-based economies is embraced worldwide. Although the idea of producing biogas and bioethanol from lignocellulosic material is not new, there are currently few regional-level comparisons of the bioenergy potential of high-diversity grasslands that would establish whether this could be a competitive bioenergy feedstock for farmers. Comparing the chemical composition and biogas yields of biomass samples from 13 grasslands in England and 73 other bioenergy feedstocks reveals that the lignin content of biomass from grasslands managed for conservation was up to 50% less than other bioenergy crops. Grasslands managed for conservation yielded up to 160% more biogas per ton dry matter than cereals or crop waste and only slightly less than Miscanthus. GIS modeling of the estimated biogas yields of grasslands managed for conservation and fields currently sown with Miscanthus show that grasslands are larger (20.57 ha) than Miscanthus fields (5.95 ha) and are projected to produce up to 117% more biogas per average field. Future incorporation of high-diversity grasslands into local and nation-wide energy plans may help reduce global fossil-fuel use in the 21st century.