A comparison of performance indices of biogas plant feedstock

Diversity indexes are used in biology and ecology to evaluate the variety of species in an area and in economics, to measure the diversification of a market. They can be applied to evaluate the performance of an energy system. In this paper, the Simpson index and the Shannon index are used to determining the diversification of the biomass available for bioenergy production. The article tries to answer the following questions: • What is the level of diversification of biomass available in a specific area? • How can diversity indexes be applied to the feedstock composition of a set of biogas plants? • Is it possible to compare the diversity indexes of a set of biogas plants with the area in which they are located? The study was carried out in an area in North-Eastern Italy, corresponding to the provinces of Verona and Padova. It resulted that the study area had a higher diversification than that assessed for 95% of the plants according to the Shannon index. The percentage was 93% when calculated by the Inverse Simpson Index. Furthermore, it was found that the percentage of utilisation of livestock waste (manure and slurry) could be increased to increment the diversification of the feedstock of biogas plants.