Decarbonization potential of fuel cell technologies in micro-cogeneration applications: spotlight on SOFCs in a Belgian case study

There is a plethora of fuel cell technologies, many of which hold great promise in terms of their decarbonisation potential, which this paper aims to explore. In fact, this paper is primarily based on the only two existing technologies on the market, polymer exchange membrane fuel cells and solid oxide fuel cells (SOFCs). Unfortunately, these commercial systems mainly use natural gas as primary fuel due to its cost and practicality (easy transport and storage, existing infrastructures, etc). Using Belgium as a case study, this paper shows that their GHG mitigation potential remains rather insignificant compared to the average individual carbon footprint if their fuel is not decarbonised. Even so, their mitigation potential would still be far from sufficient, and other measures, including behavioural changes, would still need to be implemented. Nevertheless, some emerging fuel cell technologies, such as direct carbon SOFCs (DC-SOFCs) or direct formic acid fuel cells, offer the possibility of facilitating pure CO2 capture at their anode outlet, thus allowing for potential negative emissions. Using a case study of the electricity demand of an average Belgian home (with two adults) supplied by an efficient biomass-fuelled DC-SOFC, this paper shows that these negative emissions could be up to about 4 tCO2eq yr−1 . By comparison, the IPCC's Sixth Assessment Report estimated the emissions footprint that could never be mitigated, even with future net-zero CO2 emissions, to be 1 tCO2eq yr−1 per capita, implying that climate neutrality will require similar levels of carbon sequestration. In populous Western countries, natural carbon sinks are unlikely to be sufficient, and the potential negative emissions of emerging fuel cell technologies will be welcome.