Today, biomass feedstock, including wood waste and other organic materials, account for more than 50 percent of all renewable energy (power and fuel) derived in the United States alone — while biomass has long been a viable energy source throughout Europe during the past decade. According to the U.S. Energy Information Administration, biomass currently supplies about three percent of total U.S. energy consumption in the form of electricity, process heat and transportation fuels (ethanol and biodiesel).

Biomass energy uses natural materials, such as trees, plants, agricultural and construction waste and other organic materials to generate electricity or transportation fuels. Biomass generating facilities typically use these natural materials in one of two methods — direct-fire or cofiring boilers.

The majority of today’s biomass power plants use direct-fire systems that are similar to most fossil-fuel-fired power plants. Biomass fuel is burned in a boiler to produce high-pressure steam, which is introduced into a steam turbine, where it flows over a series of turbine blades connected to an electric generator.

As the steam flow causes the turbine to rotate, the electric generator turns and electricity is produced. Cofiring plants substitute biomass for a portion of coal or natural gas in an existing power plant furnace. This method is considered the most economical near-term biomass generation option since a majority of the existing power plant equipment can be used without major modifications.

Another process is cogeneration, where the spent steam from the electricity-producing process is used for manufacturing processes or to heat buildings. Such combined heat and power systems greatly increase overall energy efficiency.