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All About Biomass Energy and Biofuels

Biofuels have the power to help reduce our dependency on foreign oil, as well as greatly reduce greenhouse gas emissions.

Biomass is organic material that comes from plants and animals and can be used for fuels, power production, and products that are typically made from petroleum. Sources of biomass include food crops, agriculture Current ethanol production is primarily from the starch in kernels of field corn. NREL researchers in the DOE Biofuels Program are developing technology to also produce ethanol from the fibrous material (cellulose and hemicellulose) in the corn stalks and husks or other agricultural or forestry residues.or forestry residues, grassy and woody plants, oil-rich algae, organic components of municipal and industrial wastes, and fumes from landfills.

Biomass energy, also referred to as “bioenergy,” is energy from plants and plant-derived materials. There are different types of biomass and processes for different purposes and applications. The most common biomass energy applications include biofuels, biopower, and bioproducts. Biofuels are created by converting biomass into liquid fuels used for transportation. Biopower refers to electricity that is generated through burning biomass directly or converting it into gaseous or liquid fuels that burn more efficiently. Bio-based products are products that are typically made from petroleum, such as plastics, that are instead created by biomass converted into chemicals.

McNeil Generating Station at Burlington, VT - a biomass gasifier which operates on wood chipsBiofuels are the only renewable liquid transportation fuels available. They can help reduce our dependency on foreign oil and can also greatly reduce greenhouse gas emissions. Biomass contains stored energy from the sun that is released as heat when it is burned. When biomass is burned it releases about the same amount of carbon dioxide as burning fossil fuels, but biomass releases carbon dioxide that was mostly captured when it was growing, which is most likely within this century. Fossil fuels release carbon dioxide that was captured through photosynthesis millions of years ago. The amount of carbon dioxide that is released from biomass is roughly equivalent to the amount of carbon dioxide captured during photosynthesis, so it is more of a trade-off cycle. Biomass can be burned directly for its energy, such as burning wood to create heat; it can be converted into a fuel source, such as fermenting corn and sugar cane to produce ethanol; or it can be converted into chemicals to create molded plastics, insulation, and other various petroleum based products. 

Biomass energy has been in use since people began to burn wood to create fires for warmth and for cooking. Wood is still the largest biomass energy source used today.

Photos courtesy of NREL/DOE.

Liquid or gaseous fuels can be created from biomass and are called biofuels. Biofuels are used for transportation and sometimes to generate electricity. The two most common types are ethanol and biodiesel. Ethanol is mainly made from the starch in corn grain and can help increase octane as well as reduce toxic air emissions. Biodiesel is made from sources such as new and used vegetable oils and animal fats. It fuels diesel engines and is a nontoxic, biodegradable, and cleaner-burning replacement for petroleum-based diesel fuel.

Creating biofuels is a complex process. Biochemical and thermochemical conversion processes are the most common, but photobiological conversion processes are also being explored. To learn more, please visit Biofuel Conversion Basics.

Hand holding corn kernels for ethanol

Corn kernels for ethanol production.

Hand holding soybeans for biodiesel

 Soybeans for biodiesel production.

Biopower is the production of electricity or heat from sources of biomass. There are various types of biopower technologies in use today: direct combustion, co-firing, gasification, anaerobic digestion, and pyrolysis.
Gasification plant- The McNeil Generating Station in Burlington, Vermont
McNeil Generating Station in Burlington, VT
Photo Courtesy of NREL/DOE

Direct Combustion
Direct combustion using conventional boilers is the technology responsible for the most electricity generated from biomass. The boilers most commonly burn waste wood which produces steam. The steam spins a turbine, which activates a generator, creating electricity. Some plants also use the steam for heating or for manufacturing processes making it a combined heat and power facility.

Co-firing systems replace a portion of petroleum-based fuel with biomass in high-efficiency coal-fired boilers. Many coal-fired power plants use co-firing systems to reduce emissions significantly and are a least-cost renewable energy option for many power producers.

Gasification systems convert biomass into a gas mixture of hydrogen, carbon monoxide, and methane using high temperatures and a controlled amount of oxygen. This gas mixture, called synthesis gas or syngas, fuels a gas turbine that turns an electric generator, creating electricity. For more information on gasification, please visit, Biomass - How it Works.

Anaerobic Digestion
Anaerobic digestion produces biogas and digestate from the natural breakdown of biodegradable organic material by microorganisms in the absence of oxygen. Woody sources of biomass cannot be used in anaerobic digestion as the microorganisms cannot breakdown the lignin found in wood. For more information, please visit our section on Anaerobic Digestion.

Pyrolysis is a process where biomass is heated in the absence of oxygen, creating liquid called pyrolysis oil. Pyrolysis oil can be burned in order to generate electricity, like petroleum.

Scientists at the National Renewable Energy Laboratory (NREL) are developing technology to create ethanol from agricultural residues such as the stalks, leaves, and husks of plants. Creating liquid transportation fuels from microscopic algae, or microalgae, is also being researched at NREL, along with using dedicated energy crops in order to grow material that is sustainable on land that cannot support intensive food crops. For more information on current and future biofuel technologies, please visit NREL’s Biofuels Basics.
Large scale algae biomass production
Large scale algae biomass production (Photo courtesy of NREL/DOE)

NREL is also working on major biorefinery development projects. Biorefineries are similar to oil refineries and will convert biomass into fuels, chemicals, materials, and products. For more information on biorefineries and NREL’s biorefinery concept, please visit NREL: Biomass Research.

Biomass is listed as a Class I renewable energy source as defined in the Connecticut General Statutes (CGS) Section 16-1(a)(26)(xi). There are proposals for biomass plants within CT as well as a plant in operation.  Plainfield Renewable Energy biomass plant in Plainfield, CT is an operational 37.5MW facility that is a Class 1 renewable biomass plant. 

On January 31, 2014, Connecticut’s Department of Energy and Environmental Protection announced that three long-term power contracts were awarded for Renewable Energy Certificates (RECs) from biomass facilities. These contracts will support up to 3.5% of the State’s load and help to meet Connecticut's Class I Renewable Portfolio Standard (RPS) requirements. For more information, please see Contracts Announced for Renewable Energy Certificates

If you are interested in learning more about biomass in Connecticut as well as Connecticut agencies involved in biomass, please visit the Department of Energy and Environmental Protection's Biomass page. For more information on using biomass at your home or business, please visit the Clean Energy Finance and Investment Authority (CEFIA).