February 21, 2007

Clean and Efficient Biogas Fuel Cells

What will be the next technological breakthrough in clean electricity generation? Some say "biogas fuel cells." Here are parts of an article from the Biopact Blog about biogas fuel cells that explains what makes them so revolutionary.

Biogas fuel cell delivers heat and power: the world's cleanest and most efficient energy system?

A milestone development in Germany is taking us towards what is probably the most efficient and cleanest energy system imaginable: biogas powered fuel cells.

In Europe, biogas is being developed on a large scale for the production of fuels for stationary power generation (to be used in natural gas plants), as well as for the transport sector (earlier post). It is being fed into the natural gas grid on a large scale (earlier post) or in dedicated pipelines supplying cities (earlier post), while some are creating real biorefineries around it that deliver green specialty chemicals, fuels and power (earlier post). The green gas can be made by the anaerobic fermentation of biomass, either obtained from dedicated energy crops (such as specially bred grass species or biogas maize), or from industrial, municipal or agricultural waste-streams. Of all biofuels, biogas delivers most energy per hectare of crops. It is also the least carbon intensive production path, with some biogas pathways actually delivering carbon negative bioenergy (earlier post). In Germany, some project the potential for biogas to be so high that it might replace all natural gas imports from Russia (earlier post).

Meanwhile, new fuel cells are being developed that do not require hydrogen to function, but that work on all common types of biofuels, from biomass-based syngas to ethanol and biogas. The latter fuel path is far more feasible for large-scale power generation than hydrogen, the production of which is inefficient, very costly and not very clean (if derived from fossil fuels; in case the hydrogen is made from biogenic processes and biomass, it is renewable and carbon-neutral, but currently, biohydrogen production is not very efficient). Now combine the efficiency of these fuel cells - which is far higher than power plants using combustion engines - and the low carbon footprint and efficiency of biogas production based on organic waste, and we have what is probably the cleanest and most efficient large-scale energy system currently in operation on earth.

"Utilising biomass to produce energy by digestion and a fuel cell not only improves energy efficiency, but also protects the climate and points the way to the future", as district administrator Maier said in praise of this intelligent and exemplary approach to municipal energy projects. The overall efficiency of the fuel cell for generating electricity and heat is 70%, which is accompanied by a dramatic reduction in emissions of harmful substances. These values cannot yet be achieved using other approaches.

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1 comment:

Unknown said...

Dear Sir,

Are bio-gas fuel cells commercially available in small sizes suitable for running on bio-gas generated from cowdung.


B K Gupta