Assessment of Biogas Station Impact on Material Productivity of Agricultural Complex

摘要

In search of alternatives for replacing fossil sources with renewable ones, intensive construction of biogas cogeneration power plants started in Latvia in 2008. Maize silage and manure are the most popular substrates used, yet, other alternatives are searched for and tested. It has to be assessed how the energy sector sustainability strategy can impact resource management in the agriculture sector. The aim of this paper is to determine how the introduction of the biogas station in typical agricultural complex consisting of farm and arable land has affected its material productivity. In this paper the biogas production impact on material flows and productivity were evaluated by applying material flow analysis to the case study object which is a traditional intensive farm in Latvia but now reoriented towards the production of electrical and thermal energy. The case study showed that introduction of the biogas station into the traditional farm caused materialization of this economic system, because eco-efficiency (economic output divided by material input) decreased by 41%. The main conclusion is that the biogas production from the biomass is favourable from energetic point of view but current renewable-energy policy in some cases can cause inefficient use of materials putting pressure on surrounding environmental systems and resource depletion.