The article focuses on calculating the energy efficiency and environmental impact of using combined heat and power (CHP) technology with bio-based fuel in energy systems. By considering factors like Primary Energy (PE) and CO2 emissions, they developed a model to assess the efficiency and emissions of heat supplied by CHP plants that use biomass. The model accounts for energy consumption and Life Cycle Assessment methods, analyzing data from various sources like producers and the Ecoinvent database. The researchers looked at a typical Norwegian district heating grid, factoring in temperature variations across seasons. They found that CHP plants' efficiencies can be calculated accurately using tools like SteamPro and GTPro, accounting for variations in heat supply throughout the year.