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Biomass

Biofuels – and specifically, biodiesel – have obtained recent popularity in the transportation sector as an alternative to gasoline. However, biomass can also be directly burned in a boiler to generate electricity. “Biomass” is a broad term that applied to food crops, grassy and woody plants, residues from agriculture or forestry, and other organic components of municipal and industrial wastes. In some cases, the fumes from landfills are classified as a biomass energy source [1]. These substances are used as fuels in direct combustion power plants. Similar to processes for traditional energy sources, burning biomass in a boiler produces high-pressure steam and the steam turns a turbine connected to an electric generator; the electric generator turns and electricity is produced [2].

In another process, biomass can be gasified prior to combustion. This is a beneficial process in that gases generally burn cleaner and more efficiently than solids, which allows for easier removal of toxic materials [3]. This process also makes possible combined-cycle processes, such as used in the latest natural gas power plants. Using gasification, combined-cycle natural gas power plants can achieve much higher efficiencies [3]. Furthermore, in many cases, the steam produced is used for a secondary purpose such as drying vegetables or for use in a factory. This dual usage is often called “cogeneration” [4].

Today, biomass electrical generation is second only to hydropower as a renewable energy source [3]. The technology’s recent rapid development can be accredited to the many benefits of biomass power; primarily that biomass has the potential to greatly reduce greenhouse gas emissions. Although burning biomass releases about the same amount of carbon dioxide as burning fossil fuels, biomass releases carbon dioxide that was captured during its own growth, thus being essentially “carbon neutral” [1]. Furthermore, the use of biomass can reduce dependence on foreign oil because domestic sources can be used. Finally, biomass energy supports domestic agricultural and forest-product industries, boosting the nation’s economy [1].

The future of biomass is very promising in the realms of electricity generation and transportation fuels. With the realization of successful economics for dedicated energy crops, biomass could be developed to contribute strongly to the world's total energy needs within several decades [5]. Tomorrow’s biomass electric generation plants will use advanced technology such as hydrolysis of cellulosic biomass to sugars and lignin and thermochemical conversion of biomass to synthesis gas for fermentation to produce biopolymers and fuels [6].