Bioenergy Europe’s role: Project Partner
The Green Pellets project demonstrated that new dedicated energy herbaceous crops for solid biomass is an effective, sustainable and eco-friendly bioenergy source for heating purposes in Western France.
The main objective of Green Pellets project (supported by Life+) was to demonstrate that new dedicated energy herbaceous crops for solid biomass provide an effective, sustainable and eco-friendly bioenergy source for heating and significantly reduce the greenhouse gases emissions. Crops dedicated to solid biomass have environmental advantages such as purification capacities or soil erosion prevention. Energy crops development must be carefully managed in order to reach an acceptable balance between food and non-food supply while avoiding any risks for the environment.
The pellet combustion (in this case pellets made from new dedicated energy crops) testing results showed that the formation of ash slagging is a pertinent problem; therefore, the boiler should be equipped with mobile grates and/or a scraper in order to avoid disrupting the combustion process and damage the material. Even when applying the recommendations of Obernberger – reducing the threshold by half compared to what is required by the French standard NF 444 – certain fuel types resulted in high amount of HCl (inorganic chlorides acid that causes the chimney and boiler corrosion). In order to avoid this corrosion, it is necessary to use ceramic exhaust pipes and to ensure that the exhaust gas temperature is kept high and condensation is avoided.
Combustion of pellets made from wheat straw, rapeseed straw or reed straw result in higher HCl and SO2 emissions. The possibility to use these sources in the boiler might be questionable if the future tests confirm the first test results.
The second set of tests is taking place at the moment and will allow to become certain about the results received during the first testing. Furthermore, the mix of reed wood, miscanthus and mowed wood are being tested to identify the best fuel types for combustion purposes.