Biomass is almost any material of organic origin, i.e. both plant and animal origin. In the context of power sources it is usually wood waste, straw and other agricultural remains and waste but also excrements of utility animals. Biomass incineration does not lead to an increase of CO2 in the atmosphere because the amount of CO2 that is released from the biofuel in the process of incineration into the atmosphere is equal to the amount of CO2 that is absorbed annually by plants in the process of photosynthesis and keep it in the form of biomass. Biomass is mainly a renewable source of power. By biomass incineration the unrenewable sources of power as coal, natural gas or crude oil are not used up.