BIOCORE aims to reveal how biorefineries can be implemented within defined local contexts. To achieve this, critical factors such as feedstock availability, logistics and various impacts will be examined and accounted for during the course of the BIOCORE project. Specific actions aim to critically analyze regional availability of lignocellulosic biomass feedstocks (straws, hardwood and SRC wood) in different parts of Europe and India and optimize their supply for BIOCORE biorefineries in an ecomically and environmentally sustainable way.
The first step in this research work was to assess biomass availability at a macro-level in different parts of Europe and India. Using a variety of reliable data sources, the availability of targeted feedstocks such as hardwood, SRC poplar, maize straw, and Miscanthus (Europe), rice straw (India) and wheat straw (Europe and India) was assessed, taking into account the different competitive uses of the raw materials (i.e. domestic, agricultural and industrial uses).
To model the functioning of biorefineries and to investigate the effects of different geographical, social, economic and political contexts, BIOCORE is using a case study approach. At the end of the first year the sites of these studies were defined (Beauce in France, Rhineland-Palatinate region in Germany, western Hungary and Faridkot and Sangrur regions in the Punjab state of India). Therefore, during the second year it was possible to further define the study content, including a description of the predicted business environment in 2025. Regarding India, it is clear that the main feedstock will be rice straw and that the biggest hurdle for its use will be the development of appropriate field to factory logistics. For Germany, it appears that woody biomass availability is compatible with the implantation of a BIOCORE biorefinery, which would require 6% of current hardwood felling or approx. 2% of total wood felling. For France and Hungary, investigations are ongoing and local stakeholders are being consulted. Beyond the further definition of the case studies, methods have also been devised to assess environmental impacts from the “field” (crop and forest production), to the “factory gate” and a modeling tool for supply mobilization pathways has been finalized.
In recent years, many studies have attempted to evaluate the usefulness of lignocellulosic niche crops for biorefining purposes, but generally these have not taken into account sufficiently diverse criteria describing economics, ecology and process compatibility.
In BIOCORE a multi-criteria evaluation has been conducted by NOVA for seven niche crops, SRC poplar and willow, Miscanthus, hemp, switchgrass, reed canary grass (RCG) and SRC eucalyptus. The full report can be downloaded from [Link here].
Each of these crops was evaluated according to 21 criteria grouped into the three categories: ecology, economy and process compatibility. Ecological criteria included effects on landscape and soil quality, biodiversity, invasiveness and fertilizer demand. Economic criteria ranged from expected yields under commercial cultivation to available cultivation technology, practical cultivation experience and availability of adapted varieties. Process suitability was evaluated with respect to preparation costs, homogeneity and composition of the valuable components cellulose, hemicellulose and lignin. Data for each of the evaluated criteria were collected from literature and expert interviews.
Scores were attributed to each of the seven niche crops for each criterion on a scale from 1-3 with 3 being the best score. Each criterion was weighted according to its assumed importance for the suitability of a crop as a biorefinery feedstock, the weights summing up to unity. The total score of a crop results from multiplying and adding up the respective weights with the score values. The results of this approach are naturally sensitive to the weights assigned to each criterion. Depending on the objective – e.g. more oriented towards economic feasibility or more towards ecological harmlessness – the weights may differ.
Figure 3 shows the total scores of the niche crops as the result from the multi-criteria evaluation. SRC poplar and willow turned out best, owing largely to the highest total content of cellulose, hemicellulose and lignin of all evaluated crops, experience in cultivation (see Figure 1 for cultivation areas in the EU in 2008) technology and being feedstocks of high density and homogeneity. Miscanthus follows, being a high yielding, perennial crop with also extensive cultivation experience in Europe.
Switchgrass is in many aspects comparable to miscanthus but cultivation experience in Europe has not yet exceeded research trials. Eucalyptus also has many advantages but has severe ecological effects, namely loss of biodiversity and antibiotic effects on soil microorganisms. RCG is currently cultivated in large scale only in Finland, is characterised by comparably low yields and moreover is the only one of the evaluated crops that has been shown to be invasive. Finally, hemp is likewise characterised by relatively low biomass yields, comparably high fertilizer demand and poses serious problems in the feedstock preparation due to the strong plant fibres. However, hemp is also characterised by the largest content of cellulose in its dry matter (see Figure 2). Therefore, if the focus of biorefinery processes lies more on this fraction, the result for hemp would be slightly better.
In conclusion, the approach used for a multi-criteria evaluation of potential biorefinery niche crops has been shown to be practical and transparent and led to sensible and helpful results. Although these results are sensitive to the choice of weights and scores, they show a general trend and provide a good basis for argumentation for or against the inclusion of potential feedstocks in further analyses.
Figure 1: Cultivation area of niche crops in the EU 2008
Figure 2: Average shares of cellulose, hemicellulose, lignin, extractives and ashes in the dry matter of selected niche crops
Figure 3: Total scores of seven ligno-cellulosic niche crops for the suitability as a biorefinery feedstock
Authors: Stephan Piotrowski, Michael Carus. nova-Institute, Germany.