Biomass - Biomass Sources

Biomass Sources

Biomass is all biologically-produced matter based in carbon, hydrogen and oxygen. The estimated biomass production in the world is 146 billion tons a year, consisting of mostly wild plant growth. Biomass energy is derived from six distinct energy sources: garbage, wood, plants, waste, landfill gases, and alcohol fuels.

Wood energy is derived by using lignocellulosic biomass (second generation biofuels) as fuel. This is either using harvested wood directly as a fuel, or collecting from wood waste streams. The largest source of energy from wood is pulping liquor or “black liquor,” a waste product from processes of the pulp, paper and paperboard industry.

Waste energy is the second-largest source of biomass energy. The main contributors of waste energy are municipal solid waste (MSW), manufacturing waste, and landfill gas. Energy derived from biomass is the largest non-hydroelectric renewable resource of electricity in the U.S., where waste-to-energy power plants generate enough electricity to supply 1.3 million homes.

Sugars and oils (first generation biofuels), such as sugarcane and corn, are used to produce bioethanol, an alcohol fuel. Alcohol fuels can be used directly, like other fuels, or as an additive to gasoline. Second generation biofuels are less simple to extract or process, while first generation biofuels are more prone to escalating the Food vs. Fuel dilemma.

Plant energy is produced by crops specifically grown for use as fuel that offer high biomass output per hectare with low input energy. Some examples of these plants are wheat, which typically yield 7.5-8 tons of grain per hectare, and straw, which typically yield 3.5-5 tons per hectare. The grain can be used for liquid transportation fuels while the straw can be burned to produce heat or electricity. Plant biomass can also be degraded from cellulose to glucose through a series of chemical treatments, and the resulting sugar can then be used as a first generation biofuel. The use of plants as a biofuel source not only provides sustainability but also a way to reduce a major greenhouse gas, carbon dioxide.

Biomass can be converted to other usable forms of energy like methane gas or transportation fuels like ethanol and biodiesel. Rotting garbage, and agricultural and human waste, all release methane gas—also called "landfill gas" or "biogas." Crops, such as corn and sugar cane, can be fermented to produce the transportation fuel, ethanol. Biodiesel, another transportation fuel, can be produced from left-over food products like vegetable oils and animal fats. Also, Biomass to liquids (BTLs) and cellulosic ethanol are still under research.

There is a great deal of research involving algal biomass due to the fact that it’s a non-food resource and can be produced at rates 5 to 10 times those of other types of land-based agriculture, mainly corn and soy. Once harvested, it can be fermented to produce biofuels such as ethanol, butanol, and methane, as well as biodiesel and hydrogen. Algal biomass may be produced commercially for this specific purpose or as a byproduct of nutrient removal systems like the Algal Turf Scrubber used to re-oxygenate aquatic dead zones and waste water treatment. Efforts are being made to identify which species of algae are most suitable for energy production. Genetic engineering approaches could also be utilized to improve microalgae as a source of biofuel.

The biomass used for electricity generation varies by region. Forest by-products, such as wood residues, are common in the United States. Agricultural waste is common in Mauritius (sugar cane residue) and Southeast Asia (rice husks). Animal husbandry residues, such as poultry litter, are common in the UK.