Landfill gas (LFG) is usually suited for energy utilization. LFG utilization can substitute fossil fuels, hence, avoiding greenhouse gas (GHG) emissions. The magnitude of avoided GHG emission depends on different factors such as; amount LFG, proportion of methane in LFG, utilization techniques and the type of replaced fossil fuel. In this study, three alternative LFG utilization options are considered to estimate the avoided GHG emissions by formulating different scenarios. The magnitudes of avoided GHG emissions are estimated when utilization substitutes particular fuels as oil, coal, natural gas and recovered fuel. Additionally, the magnitudes of avoided GHG emissions are calculated when utilization substitutes average and marginal energy production.
The study shows that GHG emission estimations include many factors which can vary widely, thus, affecting the estimated results significantly. The differences between electricity and district heat markets have to be also taken into account as variables. This is because the district heat is usually used seasonally and locally whereas electricity can be used continuously via national or international grid. On the other hand, the magnitude of avoided GHG emissions depends strongly on the type of replaced fossil fuel or fuel mix. Therefore, the use of appropriate data for describing replaced fuel or fuel mix is essential in order to carry out estimation of GHG emissions correctly. It is recommended that assumptions and definitions have to be done carefully and case data have to be used specifically. However, even if estimations include many challenges, if it is carried out with good quality, it can offer useful information for decision-makers and significantly improve landfill gas utilization.
Keywords: Landfill gas, greenhouse gas, LFG utilization