Direct combustion is the burning of biomass in the presence of oxygen. Boilers and furnaces are typically used to drive turbines to produce electricity or to produce steam to be used in district heating/cooling systems. Biomass burns in a combustion chamber, converting the biomass into heat, in a furnace. In there, the heat is distributed in the form of water or hot air. The heat of combustion is converted into steam in a boiler. The steam can be used to produce mechanical energy, electricity, or heating and cooling. Roughly 60-85% of the energy in biomass fuel could be found in a boiler’s steam.

 

Co-firing is a practice that permits biomass feedstocks to be used early on in the renewable energy transformation. It is the combustion of a fossil-fuel, like natural gas or coal, with a biomass feedstock. Numerous advantages are associated with co-firing, especially when electricity is an output. It is clear that fossil-fuel power plants are highly polluting in terms of GHSs, CO2 , and sulfur. To co-fire biomass may be a cost-effective way to meet the more stringent emission targets if we utilized exiting equipment with some modifications. The low sulfur content of biomass fuel allows it to potentially offset the higher sulfur content of fossil fuel. 

 

 “Biomass can also be used in co-generation, also called combined heat and power (CHP) which is the simultaneous production of heat and electricity. All power plants produce heat as a by-product of electricity production, and this heat is typically released to the environment through cooling towers (which release heat to the atmosphere) or discharge into near-by bodies of water. However, in CHP processes, some of the “waste heat” is recovered for use in district heating. Co-generation coverts about 85% of biomass’ potential energy into useful energy.” (Citation T-28).