Analysis of the overall potential for electricity production from farm animals manure in Bulgaria

Abstract

The increasing energy demand combined with the policies for environmental protection are prerequisite to combine them both into the circular economy conception. The utilization of organic waste which produce greenhouse gases during its disposing through production of electricity by obtained secondary organic compounds is a promising approach for the simultaneously meeting of energy needs and decreasing of carbon footprint from the industry. The successful integration of such technology with well-defined economical and technological benefits is optimization task at local level for each country, city or area. An initial evaluation of the potential of manure generated from farm animals in Bulgaria to be utilized as energy source as a different approach for its treatment to reduce the local generation of greenhouse gases is performed in this study. The well-known and commercialized technology for production of biogas from manure by digestion in biogas reactors where at different treatment conditions could be obtained gas mixtures with up to 65 vol. % content of methane is used. The main challenges in front of the implementation of this technology is the impossibility to collect all of the produced manure and also the high transportation costs for its utilization at a centralized site for biogas production and thereafter its combustion in a large power plant. A conservative analysis of the manure quantity available for utilization from different livestock animals and poultry in Bulgaria is performed based on the statistical data for the available farms and the share of free grazing animals. The contribution of different animals to the biogas production and the calorific value based on the gas mixture content are calculated in details. Unlike most other green energy technologies, this one is characterized by 24-hour availability and according to the calculated data a power plant of 1500 MW thermal power could be realized. The reduction of greenhouse gases emissions and potentially spared CO2 emissions quotas at country level are also calculated. As additionally noted there is a secondary commercial product of the anaerobic manure treatment in bioreactors, the solid residue which is applicable as fertilizer for plants due to its high nutritional value.