Landfill gas-to-energy as a contribution to greenhouse gas reduction

Landfills are found throughout the world and represent the prevalent method of waste disposal globally. Landfill gas, composed of approximatlye equal proportions of methane and carbon dioxide, is acknowledged as a significant contributor to greenhouse gas emissions. Methane is one of the short-lived climate pollutants, requiring urgent action to mitigate. However, landfill gas also represents a potential source of ‘green’ power where it is extracted and combusted in a power generation facility. Landfill gas-to-energy projects therefore have the potential for a dual contribution to greenhouse gas reduction through mitigation of methane emissions and avoidance of fossil-fuel power. In addition, landfill gas extraction and combustion represents a key component of sustainable landfill management practices, essential for reducing the risk of gas migration and associated human and environmental impacts. Given the available and proven technology, and the cross-benefits of improved landfill gas management, landfill gas-to-energy could be viewed as a ‘low hanging fruit’ for greenhouse gas mitigation. However, despite widespread adoption of landfill gas-to-energy projects in Northern European countries, North America, and metropolitan Australia and New Zealand, the majority of landfilled waste at the global level is not subject to gas capture and extraction systems. Barriers to growth in projects include technical limitations in some poorer regions, but are primarily due to weak regulatory environments and lack of financial incentives. Historically, the major drivers for development of landfill gas-to-energy projects have been regulatory requirements and revenue generated through a combination of power sales, carbon credits and/or renewable energy certificates. At both the international and national level, uncertainty in policies governing carbon and renewable energy markets, and the consequent market instability, have compromised the growth of investment in landfill gas to energy.