Alternative maize ensiling techniques for anaerobic digestion process: Economic and energetic comparison

Currently, biomasses contribute to the European energy supply-chain by an average amount of 4%. With reference to the Italian situation, in the last years about 10% of the overall maize area is earmarked to biogas production causing a changing in its harvesting operations. In particular, due to the wide surface to collect in a short harvesting period, the mowing, chopping, transport and ensiling operations must be well adapted in order to avoid bottlenecks that otherwise would lead to unproductive periods of delay, idle machines and, as a result, higher costs that could reduce the overall efficiency. Ensiling, in this sense, is one of the key issues that could affect the sustainability of such biomass, both from an economical and environmental point of view. In fact, several ensiling techniques can be carried out. However, among them, in Europe, the two most widespread are: bunker silos (traditional systems) and plastic bag-silos. While the bunker silos represent so far the most utilized solution, the plastic bag silos could be a potentially cheaper alternative to traditional silage storage systems. The aim of this study is to compare the economical and energy aspects of the two most important ensiling techniques for maize silage production aiming to detect the solution having lower costs and impact on the environment.