The technical and economic research is to develop the concept of the biogas plant using by-products and wastewater from production in the factories based on the processing of sugar beet. And also the exact technological aspects of the biogas plant were presented. The subject of study on working biogas plant was carried out on the basic information from some of a Polish Sugar Plant and fulfilled by literature. Industrial assumptions are presented, such as raw materials for biogas production, currently owned technical infrastructure and land development. The concept of biogas plant installation with division into individual objects is presented. The purpose of this article was to develop the economic analysis for biogas plant working at sugar factory and to show the energy balances and material and then calculated the main economic indicators such as Cash Flow (CF), Net Present Value (NPV), Internal Rate of Return (IRR) and Discounted Payback Period (DPP). It was found that the biogas plant operating at a sugar factory can be a profitable investment and DPP amounted to 4 years. However, these results are estimates and in reality they may changed.