Turning feedstock waste into electricity Fuel cells convert the chemical energy in fuels such as hydrogen or methane into electrical energy to power devices. EU-funded researchers developed novel wood-powered fuel cells with reduced sensitivity to pollutants and excellent efficiencies that promise to be particularly useful for decentralised power generation in Mediterranean countries. Energy © Thinkstock High temperature solid oxide fuel cells (SOFC) have been the focus of much developmental activity. They rely on available fossil fuels and their existing transport and supply chain. In addition, they are inexpensive and extremely efficient. Finally, fuel cells are clean, green and reliable (no need to worry if it’s going to be a sunny or a windy day). An innovative way to supply flammable gas to SOFC is by the so-called gasification of biomass, releasing flammable gases such as methane, carbon monoxide and hydrogen from the burning of organic waste. These gases can then be used to feed fuel cells in automobiles or electrical generator. The ‘Biomass fuel cell utility system’ (Biocellus) project was initiated to address two of the main challenges facing the use of biomass and agricultural residues in SOFC, particularly in Mediterranean and southern European countries. First, the use of SOFC requires innovative gas cleaning technology to remove pollutants such as tar from the gasified biomass. Secondly, the systems must be highly efficient even at relatively low power outputs. The investigators assembled single SOFC test rigs and tested them at different sites producing gas with varying amounts of tar to determine the requirements for the gas cleaning unit. The SOFC was functional even with relatively high tar levels in the biogas. In addition, the researchers determined that hot (over 600 degrees Celsius) gas cleaning, the introduction of heat pipes and use of anode materials resistant to carbon deposition were all necessary to ensure high efficiencies of a SOFC stack design integrated with a biomass gasifier. The test systems demonstrated minimal degradation due to woody gas, high efficiency and the highest power output of a SOFC system operating on wood gas reported in the literature. In summary, the Biocellus project advanced the state of biomass-fed fuel cells, producing high-efficiency high-performance units for the conversion of biomass feedstock to electrical energy. Small agricultural units in Mediterranean and southern European countries may now be able to use their organic waste to supply electrical power to their farms, homes and equipment, decreasing costs and increasing competitiveness while protecting the environment.
