An economic and environmental assessment on landfill gas to vehicle fuel conversion for waste hauling operations

The objective of this work was to use an economic and environmental life-cycle assessment (LCA) to investigate the viability of converting landfill gas (LFG) to different vehicle fuels for a real-world tractor-trailer fleet that hauls municipal solid waste (MSW) from a typical transfer station to a nearby landfill. Four scenarios were analyzed: two conventional scenarios that examined the impacts of using diesel as a vehicle fuel with typical LFG management practices and two that assessed the advantages/disadvantages of using LFG as a feedstock for producing two types of alternative vehicle fuels. Producing LFG-derived compressed natural gas (CNG) or electricity as an alternative fuel source for the fleet is generally found to be significantly more economically and environmentally advantageous than practicing one of the more conventional scenarios, especially as the value of financial incentives (e.g. RINs) increase. The LFG-to-CNG scenario offers the greatest financial benefit when these incentives are high. However, when financial incentives are not available, this scenario is not feasible to undertake in the system modeled, but an LFG-to-electricity scenario could still save $1.32 for every gallon of diesel that is replaced with the alternative fuel. Using LFG-derived electricity as a vehicle fuel substitute also offers greater financial benefits than using the same volume of LFG for more commonplace purposes, such as generating electricity that is fed to the grid. Additionally, from the LCA, this scenario has the lowest global warming potential of all four scenarios analyzed, with over a 50-fold reduction in CO2-equivalent emissions over the baseline scenario.