Biomass is solar energy stored in organic matter. As trees and plants grow, the process of photosynthesis uses energy from the sun to convert carbon dioxide into carbohydrates (sugars, starches and cellulose). Carbohydrates are the organic compounds that make up biomass. When plants die, the process of decay releases the energy stored in carbohydrates and discharges carbon dioxide back into the atmosphere. Biomass is a renewable energy source because the growth of new plants and trees replenishes the supply.

Over millions of years, natural processes in the earth transformed organic matter into today´s fossil fuels: oil, natural gas and coal. Fossil fuels are not renewable. The oil, natural gas and coal we use today are gone forever.

The use of biomass for energy causes no net increase in carbon dioxide emissions to the atmosphere. As trees and plants grow, they remove carbon from the atmosphere through photosynthesis. If the amount of new biomass growth balances the biomass used for energy, bioenergy is carbon dioxide "neutral." That is, the use of biomass for energy does not increase carbon dioxide emissions and does not contribute to the risk of global climate change. In addition, using biomass to produce energy is often a way to dispose of waste materials that otherwise would create environmental risks.

The Department of Energy estimates that the total energy value of biomass fuel consumed in Oregon was 79 trillion Btu in 2003. This is about 10 percent of the total amount of non-transportation energy consumed in the state. Biomass supplies about 9 percent of all industrial energy consumed in the state.

Living plant material is the source of all biomass fuel. Some biomass fuel resources are waste products left over after plant materials have been used for other purposes or consumed by animals. Other biomass resources are plant materials directly harvested for their energy value. Biomass fuels are readily available throughout the world. Oregon´s biomass resources include wood, agricultural crop residue and organic waste.

The Pacific Northwest generates as much as 1,000 trillion Btu of biomass fuel each year. However, competing uses and the cost of collection and transportation limit the amount that is available for energy production. Only one-third of the total biomass fuel generated annually may be economically available for electric power production in the region.

The production of heat for industrial processes and for residential and commercial space heating consumes the largest amount of biomass fuel in Oregon. Wood products industries burn wood chips, bark and wood waste to supply heat for industrial processes. Some mills use biomass fuel to generate electricity for on-site uses. Pulp mills burn the residual fiber and lignin components of spent pulping liquor to recover and recycle pulping chemicals and to generate steam. Pellets and fuel logs manufactured in Oregon and firewood collected from Oregon forests supply heat to homes.