From waste-to-energy to waste-to-hydrogen units: A new role of waste combustion plants

The study focused on a new Waste-to-Hydrogen (WtH2) strategy, where a waste combustion plant (WCP), originally designed and operated as a Waste-to-Energy unit, provides “renewable” electricity to an electrolyser, to obtain “green hydrogen” utilised in a regional railway line. The investigation included three systems using alternative WCPs, differing for size, energy efficiency and input waste composition. A Life Cycle Assessment, with a “separate share” approach and “product&tranportation” perspective, compares trains powered by WtH2 systems, diesel or hydrogen from steam reforming, respectively. The WtH2 systems show savings ranging from 39 to 57 tCO2,eq per tonne of produced H2, and are in compliance with the EU decarbonisation targets. The WtH2 system including the co-generative large-scale plant has the best performance when all categories are evaluated as a single score (with improvements up to 180%). The main relevant contributions to the results come from the thermal energy recovery and biogenic waste avoided management.