Like other Dutch power generators, Electrabel has signed up to the ‘Coal Covenant’, a voluntary agreement with national government in which they have pledged to replace part of the coal burned in power stations by biomass. The study is a follow-up to a study dating from August 2005. In the present study, commissioned by Electrabel, the environmental strengths and weaknesses of four different alternative fuels from the earlier study were assessed: corn-cob, rice-residue, palm-seed and eucalyptus pellets.
The conclusions were as follows:
Rice-residue pellets and corn-cob pellets
The analysis was based on the premise that in the producer country Thailand the rice husks/corn cobs presently used as agricultural fertil-iser could be replaced by artificial fertilisers. In that case, co-firing the rice husks / corn cobs in the Gelderland 13 power station (G13) in pelletized form would mean an improvement in both greenhouse gas (GHG) emissions and local air quality in the vicinity of the station.
Here, the point of departure was that the portion of the eucalyptus wood not used locally in South Africa is burned there in the open air. Although local use of this biomass within South Africa would be preferable, it does not occur. Co-firing the eucalyptus wood in pelletized form in G13 is therefore again better for GHG emissions as well as local air quality around G13.
In the case of palm-seed pellets as a supplementary fuel, it depends very much on the current application whether or not there will be environmental gains. If this waste is used as animal fodder, co-firing is probably unfavourable for the environment, because it is likely to mean additional destruction of virgin rainforest or other nature. If it is used as a fertiliser or simply burned, then co-firing of palm-seed pellets is better for GHG emissions. Without additional measures (to remove additional flue-gas NOx), co-firing in G13 will mean a slight deterioration of air quality around the power station.
In general, burning these pelletized biofuels in G13 would have a net positive impact on both local air quality around the power station and GHG emissions. The exception is palm-seed pellets, which seem likely to score negatively on both these environmental indicators.