A recent study published in ScienceDirect presents a life cycle assessment (LCA) of seven renewable methane production technologies, including wind- and solar-powered electrolysis, methanation with direct air-captured CO₂ (DAC), anaerobic digestion of various organic waste streams, and landfill gas upgrading.
Using the ReCiPe 2016 method, the study found that sewage sludge digestion had the highest global warming impact due to the electricity required for digestate dewatering via centrifuge. In contrast, the anaerobic digestion of pig manure in a covered lagoon with digestate dewatering in a Geotube® exhibited the lowest impact. A direct comparison between these dewatering methods showed a 78% lower global warming impact for the Geotube® system.
Among the 11 production systems analysed, seven demonstrated lower global warming impacts than natural gas, highlighting the potential of renewable methane to reduce emissions. Increasing the efficiency of wind and solar electricity appeared to be more sensitive than increasing the efficiency of electrolysers, while the transport distance of the landfill gas had a significant effect on the global warming impacts.
To facilitate the adoption of renewable methane, policy interventions such as financial incentives, regulatory adjustments, and support for sustainable practices could play a significant role. These findings underscore the potential of renewable methane as a viable alternative to fossil-based natural gas in the transition to a low-carbon energy system.
Find the study here.
