The paper discusses three years commercial operation to date of the Biogas Cogeneration Set driven with the JMS 316 GS-B.LC GE JENBACHER type engine, which has been operating in the WARTA S.A. Sewage Treatment Plant of Czestochowa since the end of December 2008. The analysis covered the CHP Sets operation and shutdown times, number of start-ups and availability, electric energy and heat generation, and average hourly electric and thermal load; the Sewage Treatment Plants electric energy and heat balance and the degree of coverage of its electric energy and heat demand by its own production; the unit biogas consumption by the CHP Set; the service work carried out on, and failures of the CHP Set; and the economic effects gained from the operation of the Set. The study is a continuation of the authors previous publications [3, 6, 7, 8] and, jointly with them, constitutes a unique compendium of knowledge for future operators of CHP biogas sets in the form of a collection of actual operational data for one of the most representative biogas cogeneration sets operated in domestic sewage plants in terms of electric power (approx. 0.8 MW).