Browsing by Subject "biokaasun tuotanto"

The aim of this master thesis was to evaluate suitability of a biogas plant as a manure maintenance method in a kind of a horse village, where many horse businesses are located close to each other. The suitability of the biogas plant was evaluated by ecological and economic effects. For ecological effects the investigation was made concerning nitrogen and phosphorus flows and for economic effects an evaluation was made concerning the total profitability of the biogas plant. Nitrogen and phosphorus flows were investigated by substance flow analysis. The evaluation was made by investigating internal flows, flows inside and outside of the system and the size of the flows of two systems in which one system was a horse village with a biogas plant and the other system was a horse village without a biogas plant. The horse village without the biogas plant was further divided into two options. One option was to spread the manure on fields and the other option was to hand over the manure. The economic profitability was evaluated by gross margin calculation concerning four different options which were a biogas plant producing CHP with and without financial support and a biogas plant producing fuel with and without financial support. Concerning nitrogen and phosphorus flows, the horse village where the manure is spread on fields is as good option as where the manure is being processed on a biogas plant and where the digested sludge is used for fertilizer as well. Handing over the manure outside the horse village is a worse option in relation to the local substances flow cycle. The construction of the biogas plant in horse village was profitable in every options. Although manure processed by biogas plant is evaluated to produce less nutrient loss compared to manure which is spread straight to the field, there still is a need for further investigation about the effects of biogas production on nutrient flows and nutrient losses in order to model the effects of a horse village. However, according to previous investigations it is known that biogas production decrease greenhouse gas effects. The profitability of biogas plant requires that manure maintenance costs of the horse village have been quite high before the biogas plant.