Cesar Sequeira

Abstract:

R&D activity performed during the last three decades has identified four plausible, long-term markets and energy solutions that fuel cell systems may offer: lowest cost energy to end users; solutions for combined heat and power or high-value premium power; peak-shaving solutions; and load-management and grid-power support for unreliable or inconsistent supply. Accordingly, towards rapid commercialisation of fuel cell products in the coming years, the fuel cell system is being redefined by means of a strong concentration on lowering costs of basic elements, electrolytes and membranes, electrode and catalyst materials, and increasing power density and long-term stability. Among different kinds of fuel cells, low-temperature polymer electrolyte membrane fuel cells (PEMFCs) are of major importance, but their problems related to hydrogen storage and distribution are forcing the development of liquid fuels such as methanol, ethanol, sodium borohydride and ammonia. In respect to hydrogen, methanol is cheaper, easier to handle, transport and store, and has a high theoretical energy density. The second most studied liquid fuel is ethanol, but it is necessary to note that the highest theoretically energy conversion efficiency should be reached in a cell operating on sodium borohydride alkaline solution. Independently of these fuel cell types, it is clear that proper solutions need to be developed, by using novel catalysts, namely nanostructured single phase and composite materials, oxidant enrichment technologies and catalytic activity increasing. In this lecture, these main directions will be considered.