Generating Electricity with Biomass
According to the U.S. Department of Energy (DOE), biomass recently surpassed hydropower as the largest domestic source of renewable energy, and consumption in electric utilities is expected to double every 10 years through 2030. Biopower uses biomass energy systems to generate electricity through methods such as:
- Direct-fired – In dedicated direct-fired biomass operations, the boiler’s fuel is 100% biomass which is burned in a conventional steam boiler. The steam is then captured by a turbine and converted to electricity by a generator. The materials used are generally milling and logging residues and energy crops such as fast-growing trees and shrubs.
- Co-fired – Co-firing substitutes biomass for a portion of coal in an existing power plant furnace, significantly reducing toxic emissions.
- Gasification converts biofuel or biomass into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam.
- Pyrolysis converts solid biomass into an easily stored and transported liquid by subjecting the feedstock to high temperatures in the absence of oxygen.
- Anaerobic digestion is a process that captures methane from decomposing biomatter.
Renewable Electricity Generation by Energy Source
Electric energy from a power plant is measured in kilowatt-hours (kWh) and is priced in ¢/kWh.
Source: Department of Energy, Energy Information Administration, Energy Outlook 2009.
As the graph illustrates biomass is expected to remain the second-largest source of renewable electricity generation (behind hydropower) through 2030. Of all the renewable energy sources, biomass is the fastest growing, going from 11% of the total in 2007, to more than 41% in 2030.
Electricity generation from biomass, both dedicated and co-firing, grows from 39 billion kilowatthours in 2007 to 231 billion kilowatthours in 2030.
Energy Policy Act of 2005 Tax Credit
The Energy Policy Act of 2005 mandates that electricity generated from closed loop biomass (dedicated energy crop) modified to co-fire with coal and/or biomass is eligible to receive 1.5 cents per Kwh credit multiplied by the ratio of the thermal content of the closed-loop biomass to the thermal content of all fuels used in the facility.
This policy will continue to drive the adoption of biomass-generated electricity.
- Converting Biomass into Electricity is a DOE web page that illustrates the major technologoes used to convery biomass to electrical power.
- Annual Energy Outlook 2009 with Projections to 2030 is an annual publication released by The Department of Energy Energy Information Administration.
- Biopower for Electricity Providers, from the National Renewable Energy Library (NREL).