A number of thermochemical and biochemical technologies are available for the conversion of biomass into energy and fuel. The suitability of biomass as feedstock for a conversion process depends upon its composition and heating or calorific value.
LCMW biomass containing high lignin content and low ash is suitable for thermal technologies and biomass with high moisture content is suitable for biochemical technologies as well as for hydrothermal carbonization. Advanced technologies are very sensitive to feedstock variations in terms of composition, humidity, ash content etc.
The availability of technology does not guarantee the efficient feasibility of the entire process chain as the economy of scale is also one of the deciding factors. The suitable energy recovery plants are typically sized large in order to achieve viable economic operation and for that vast quantities of feedstock need to be supplied regularly in order to keep the plant running see the figure below.
The secondary X-axis indicates examples of biomass potential of selected LCMW biomass from greenGain model regions, selected countries and cumulative EU-27 + Switzerland.1 Source =BioBoost,2016
The economics of many systems appear to assume that feedstock of a known quality and quantity will be steadily and readily supplied to the plant, which is not the case with LCMW biomass. Many technologies that have been commercially proven in a full-scale plant, or that have at least demonstrated their viability have limited scope for LCMW biomass with potentials < 1000 t/y and for those mostly small scale conversion plants are favorable for recovery of energy from LCMW biomass to match the availability. For example, the amount of whole woody LCMW biomass i.e. sum of CZ-LCMW1+ CZ-LCMW2 (refer to the table 1: Potential and properties of landscape conservation and maintenance work (LCMW) biomass in the greenGain model regions; greenGain deliverable D4.2) available from the Czech model region Kněžice is only suitable for private use or in small boilers with a rated capacity of about 10 KW, whereas the woody biomass from DE-LCMW1 Hedge-and tree rows on banks from Friesland (refer to the table 1: Potential and properties of landscape conservation and maintenance work (LCMW) biomass in the greenGain model regions; greenGain deliverable D4.2) might be a suitable feedstock for heat and power plants with >1 MW capacity. Similarly, the cumulative LCMW biomass from countries e.g. like Spain and Germany with suitable transportation infrastructure have a potential utilisation as feedstock in large decentral biomass conversion plants (figure 1). In addition, all applications are strongly influenced by regulatory measures e.g. subsidy programmes (natural conservation obligations) for hedge- and tree rows, EEG incentives (Renewable Energy Sources Act) for power and heat etc. in Germany. Thus, biomass potentials, constraints such as biomass quantity and quality, frequency of supply, spatial distribution, economy of scale and existing regulations are some of the criteria that influence the selection of conversion routes for LCMW biomass.