Restoring low-input high-diversity grasslands as a potential global resource for biofuels

Abstract

Reducing meat consumption by humans and shifting to more efficient plant and animal protein sources could potentially free up large areas of pasture and feedcrop agricultural land for restoration or conversion to low-input high-diversity (LIHD) grasslands. LIHD grasslands improve biodiversity, carbon sequestration, erosion control, water storage, while also providing opportunities to produce biofuels. We examined the potential of converting pastures globally, and animal feedstock agricultural lands in the USA and Brazil, to LIHD biomass sources and the capacity of these systems to meet national energy demands via (1) cellulosic ethanol and (2) integrated gasification and combined cycle technology with Fischer-Tropsch hydrocarbon synthesis (IGCC-FT) processing. Our analyses, which we argue are conservative, indicate that large amounts of energy, far in excess of many country's current demands, can potentially be produced from IGCC-FT processing of grassland biomass grown on converted pastures, especially in tropical developing countries. Over 40 countries could meet ≥100% of their domestic demands for electricity, gasoline, and diesel. If energy products were shared between countries, the 95 countries with positive energy production yields could meet 46%, 28%, and 39% of their combined electricity, gasoline, and diesel demands, respectively. While it is clearly unrealistic to propose a 100% conversion of pasture lands to biofuel production, these analyses highlight the potential gains in ecosystem services and energy production that could theoretically be achieved on already-managed lands.