A Comparison Between the LCA of a PEMFC and an MCFC System for the Production of Electric Energy, and Traditional Energy Conversion Systems

This paper investigates the environmental impact of electric energy generation by using a PEMFC and an MCFC system. Fuel cells are considered to be ultra-clean energy conversion devices, since pollutants emissions during operation have a very low concentration, compared to those of traditional energy systems. In order to understand the real environmental impact of fuel cells, this is not enough and it is necessary to study their “cradle-to-grave” life, starting from the construction phase, to the operational life and eventually to its disposal. In fact, it is not really correct to say that fuel cells are almost zero-emission systems, because they produce not-negligible emissions during manufacturing and to produce hydrogen. The method used in this paper is the Life Cycle Assessment (LCA), which has been calculated with the software SimaPro 5.0. The functional unit chosen in this study is the production of 1 kWh of electric energy by a PEMFC and an MCFC. Thanks to this approach, the critical process related to the production of energy by the previous fuel cell systems, (i.e. the production of hydrogen by natural gas steam reforming), has been determined. After a separated LCA of the PEMFC and the MCFC, a comparison was made between the two systems, considering the environmental impact of electric energy generation. Finally, the production of electric energy by a PEMFC and an MCFC systems is compared to that by conventional energy conversion systems.