A feasibility study/investment project of the reconstruction of the main boiler house (Beržė district boiler house) of Tauragė town to refuse from using fossil fuel in Beržė boiler house was developed, the possibilities to produce electricity and sell it as a service meeting the public interest were assessed, the analysis of reconstruction alternatives of the chimney and water preparation was carried out and optimal solutions based on technical-economic analysis were selected in the paper. Analysis was carried out in the work and technical parameters and power of the new biofuel boiler were determined. Technical possibilities of the existing turbo-generator to produce electricity during the non-heating season and sell surplus electricity to the power grid were also assessed. Analysis of use of the existing brick chimney and existing condensing economizer to work with a new biofuel boiler was carried out. Recommendations were presented for the reconstruction of reserve fuel (fuel oil sector) in order to reduce the cost of storage of reserve fuel.