The project involves the modernisation of the district heating system PEC Sp. z o.o. in Ciechanów through the construction of an installation for the production of electricity and heat in high-efficiency cogeneration. The company plans to build three high-efficiency cogeneration installations: 1. Activity 1. Construction of a high-efficiency cogeneration installation using RES (biomass) – the system will operate on the basis of a steam boiler (25 bar, rated steam production 14 t/h, heat output of the furnace approx. 12.0 MW, heat output approx. 10,17 MW) biomass-fired with a turbine with a minimum electrical power of 0.8 MWel, coupled with a three-phase synchronous generator. The task will be carried out on plot no. 90-84/5 in Ciechanów, ul. The 18th millennium – the area of the existing heating plant. 2. Task 2. Construction of a high-efficiency cogeneration installation for gaseous fuel – the construction of the system will consist of the installation of a cogeneration unit with an electrical power of approx. 1,0 MWel and Ht+Lt 1,23 MWth thermal input based on the combustion of natural gas (or liquefied LNG) in container housing.