Biomass electrical generation or biopower is second only to hydropower as a renewable energy source.
Most electricity generated using biomass today is by direct combustion using conventional boilers. These boilers burn primarily waste wood products generated by the agriculture and wood-processing industries. When burned, the wood waste produces steam, which is used to spin a turbine. The spinning turbine activates a generator that produces electricity. Many coal-fired power plants also add biomass to their coal-burning process (i.e., co-firing) to reduce the emissions produced by burning the coal.
The McNeil generating station in Burlington, Vermont, showing its innovative, high-throughput gasifier, which looks like a tower. Gasifiers convert biomass directly into gas, which can be burned to generate electricity. Photo credit: Warren Gretz
Biomass can also be gasified prior to combustion. Gases generally burn cleaner and more efficiently than solids, which allows removal of toxic materials. Gasification also makes it possible to use biomass in combined-cycle gas turbines, such as used in the latest natural gas power plants. Using gasification, these natural gas power plants can achieve much higher efficiencies. Small modular biomass gasification systems are well suited for providing isolated communities with electricity.
In addition, the decay of biomass in landfills produces gas (primarily methane) naturally, which can be harvested and burned in a boiler to produce steam for generating electricity.
Where It's Available
Producing electricity from biomass is most cost effective if biomass power or biopower plants are located near biomass feedstocks. Biomass resources are abundant across the eastern half of the United States, and thus, the majority of operating biomass power plants are located there. The future use of dedicated feedstock crops can broaden the resource availability to all regions with agricultural production activity.
Biomass Resources Map
This map shows the distribution of biomass resources across the United States.