Evaluating Methanol and Liquid CO2 Recovery from Waste-to-Energy Facilities: A Life Cycle Assessment Perspective

This study investigates an integrated approach in which CO2 captured from waste-to-energy (WtE) facility flue gases is exploited to produce methanol (CH3OH), via a catalytic reaction with H2, and liquid CO2 for industrial applications. The integrated system is fully powered by energy from WtE, including the facility for alkaline electrolysis for hydrogen production. The amount of energy necessary for producing 1 tonne of CH3OH was 10.2 MWh, which can be generated by the combustion of approximately 25 tonne of waste in a typical European WtE. Under these conditions, 18.1 tonnes of liquid CO2 can also be recovered. Compared to the conventional production of CH3OH, the proposed system achieves a significant reduction in greenhouse gas emissions, about 492.3 kg CO2eq per tonne of CH3OH. Other environmental impacts, such as particulate matter, acidification, and freshwater ecotoxicity, were found to be quite similar between the two scenarios. Furthermore, the EU27 WtE systems have the potential to meet about 22 % of the current methanol demand in the area significantly contributing to the EU's goals for a circular and carbon-neutral economy.