Assessment of a novel alder biorefinery concept to meet demands of economic feasibility, energy production and long term environmental sustainability

The management of an average alder plantation in a 6-year coppicing system was found to fixate atmospheric nitrogen to the soil in yearly rates between 50 and 200 kg ha−1 and produce a 6-year total dry biomass quantity around 33 Mg ha−1 plus yearly leaf production. This production could facilitate a biorefinery to serve society with production of energy related and value added products to substitute the use of fossil fuels while at the same time replenishing degenerated soils. Integrating a biomass handling system, an LT-CFB gasifier, a diarylheptanoids production chain, an anaerobic digestion facility, a slow pyrolysis unit, gas upgrading and various system integration units, the biorefinery could obtain the following production characteristics accounted on a yearly basis: Total system Energy Return on energy Invested 2.0, total system Exergy Return on exergy Invested 1.5, Net Energy Output 78 GJ ha−1, Net Exergy Output 50 GJ ha−1, Net carbon sequestration (as CO2 equivalents) 0.80 Mg ha−1, Total product value 2030 € ha−1 and Net Dry Matter Removal of approximately 90%.