Abstract
The Life Cycle Assessment (LCA) of a solid oxide electrolyser (SOE) has been performed using publicly available data. The system for producing 1 kg of hydrogen at 25bar and 99.9% purity is represented by a modular structure, which includes the 20-kW solid oxide stack manufacturing, balance of plant equipment, operation consumables, and end-of-life processes. A parametrized life cycle inventory modeling approach was developed. The results illustrate that SOE performs better than steam methane reforming only if supplied by electricity from renewable or nuclear sources. The operation consumables have been identified as the most contributive life stage (67%-89% of potential impacts), followed by equipment manufacturing (7%-22%) and stack manufacturing (4%-11%). Considering the predominant contribution of electricity supply in the consumables, no compromise should be made on ensuring clean electricity sourcing and on the stack energy conversion efficiency. The lifetime of the stack and the balance of plant equipment, as well as the heat mix have been identified as sensitive parameters to minimize the environmental impact of the hydrogen technology. These LCA results have been used to produce a tailored eco-design process for hydrogen projects: (i) organization of an eco-design workshop to present LCA results & environmental hotspots and related key parameters where to leverage eco-design innovations through an open discussion (brainstorm); (ii) provide an eco-design tool obtained from a simplified version of the LCA model parametrized around a limited number key life cycle inventory parameters, enabling the designers/developers to independently test the environmental performance of their innovations.