Bioenergy or biomass energy—the energy
from plants and plant-derived materials—has been used since humans began
burning wood to cook food and keep warm.
Wood is still the largest biomass
energy resource today, but other sources of biomass can also be used. These
include food crops, grassy and woody plants, residues from agriculture or
forestry, oil-rich algae, and organic municipal and industrial wastes (that’s
right: poop). Even the fumes from landfills – methane, the main
component in natural gas – can be used as a biomass energy source.
Biomass in Oregon
While Oregon has some
dedicated biomass energy crops, most biomass resources are secondary products,
such as lumber mill residue, logging slash, and animal manure. Examples of
biomass resources available in the Northwest include woody biomass, spent
pulping liquor (byproduct of pulp and paper making process), agricultural field
residue, animal manure, food processing residue, landfill gas, municipal solid
waste, and wastewater treatment plant digester gas.
Oregon has 17 woody biomass power facilities, primarily in the wood-products industry. An additional 21 facilities in Oregon use woody biomass to provide space heat; these include schools and hospitals
Biomass for Electricity Generation
The most common source of
biomass-based electricity is wood. The most common method of converting biomass
to electricity is through direct-fired combustion – a similar process to that is used for coal or natural gas. After the biomass has been pre-processed to remove
impurities, it is burned in a boiler to generate steam, which turns a turbine
and generates electricity.
Biomass power plants are
typically less than 50 megawatts in size, compared to coal plants, which are typically
200 to 1,500 megawatts..