Bioenergy from permanent grassland--a review: 1. Biogas

Area of Science:

• Agricultural Science
• Energy Science
• Environmental Science

Background:

• Grassland biomass is a well-established feedstock for biogas production.
• Understanding the suitability and sustainability of grassland biomass for anaerobic digestion is crucial for optimizing bioenergy strategies.

Purpose of the Study:

• To review current knowledge on the suitability and sustainability of grassland biomass for anaerobic digestion.
• To explore grassland management, harvest, post-harvest, and digestion technologies for biogas production.

Main Methods:

• Review of existing literature on grassland management for biogas feedstock.
• Analysis of factors influencing methane yields from grass, including species, cutting period, and management intensity.
• Discussion of economic aspects and environmental impacts of using grassland biomass for biogas.

Main Results:

• Methane yields are influenced by various factors, with some well-understood (e.g., grass species) and others requiring further research (e.g., preservation, processing).
• Profitability depends on silage costs and the overall anaerobic digestion and energy utilization concept.
• Grassland biomass competes with other uses, particularly animal husbandry, with differing priorities in developed versus developing countries.

Conclusions:

• Grassland biomass offers considerable bioenergy potential, especially in developed countries with surplus grasslands.
• Appropriate grassland management can maintain or enhance environmental benefits like carbon storage and water quality while producing biogas.
• Significant reductions in greenhouse gas emissions are achievable through biogas production from grassland.