Biomass: A Key Source of Renewable Energy

Renewable biomass energy produced from wood, the dominant biomass resource in Washington, is made from slash leftover from sustainable timber harvesting operations.

For more than a century, forest product companies have created energy from wood to power sawmills and pulp and paper mills. Now, this “old technology” is being modernized and adapted on a broader scale for more efficient use of wood waste to provide renewable energy for communities in the Pacific Northwest and across the country.

Shelton, Washington

Biomass Q&A

Biomass is a renewable energy source, because the planting and growth of new plants and trees replenishes the supply, and burning biomass to generate energy is also carbon neutral. Also:

  • By thinning overcrowded and unhealthy forests, removal of woody biomass can improve the health of forests.

  • Biomass energy generation creates and sustains jobs, especially in rural areas affected by economic downturns in the timber and construction industries.

  • Biomass energy reduces our reliance on fossil fuels, and specifically reduces our reliance on imported petroleum, which can improve our trade imbalance and enhance our national security.

When wood is burned to produce energy, the carbon dioxide (CO2) that is released into the atmosphere is the same CO2 that would be released if the wood decomposed, so there is no net addition of carbon dioxide to the atmosphere. Also, forests are replanted and the new trees continue the cycle of absorbing and storing CO2 from the atmosphere. In the United States, forestlands are net carbon sinks, meaning more wood is grown than is removed. The Pacific Northwest has the highest productivity forests in the nation, and wood is the dominant biomass resource in Washington, accounting for two-thirds of all potentially available biomass.

No. Geologic carbon emissions from fossil fuels such as coal, which have been buried underground for centuries and otherwise would not be released, add “new” carbon to the atmosphere. Biogenic carbon from biomass would be released anyway as part of the natural cycle of growth, decay and regrowth. As long as the source of biomass comes from sustainable practices, biogenic carbon emission is not dirtier than coal, since it does not increase overall carbon in the atmosphere.

No. The Manomet Center for Conservation Sciences, which did the study, issued a clarification after the media misinterpreted its findings and those misinterpretations were widely reported. John Hagan, the President of the Center, and Thomas Walker, the study team leader, told The New York Times that the media reports “fail to recognize that over time using wood for energy can lead to lower atmospheric greenhouse gas levels.”1 (Emphasis added)

Despite media headlines, the Manomet report indicated that the long-term benefits of biomass fuels far outweighed fossil fuels, largely due to “recycling” trees by planting new ones that absorb carbon dioxide.

The study focused largely on the carbon cycle implications of whole trees grown specifically as biomass fuel in Massachusetts, rather than on the use of residual fiber (chips, bark, branches, etc.), which is what most biomass power plants actually utilize. In addition, the study looked specifically at impacts related to a single forest, rather than biomass from a broader region. Some readers apparently went directly to conclusions based on those parameters instead of looking over the qualifications related to the study, and leapt to incorrect assumptions of cumulative impact.

In addition to providing renewable energy, biomass power plants utilizing wood waste can provide numerous other benefits. They:

  • Help stop disease and infestation. In Inland West areas such as Eastern Washington and Eastern Oregon and other states, insects such as the mountain pine beetle have devastated millions of acres of pine forests. Removing these infected trees to utilize them as fuel can stop the spread of the insect and also provide energy while reducing the risk of catastrophic wildfire.

  • Reduce the use of prescribed fire (also known as slash burning). Forest land managers occasionally use prescribed fire to reduce the amount of logging residue known as slash. This is necessary to improve planting success, reduce wildfire risk and in some cases is required by law. Burning this fuel in a biomass plant with effective emission controls is more efficient and reduces the particulates and other substances that otherwise would be released into the atmosphere.

    • Improve forest health and sustainability. After a century of fire suppression, and abrupt lack of management on federal forests, unhealthy conditions have developed in some forests, with an unnatural amount of trees or trees that are not well adapted to the site. Thinning the forest and removing undergrowth to utilize it for energy production, while leaving the hardiest trees in place, helps make the forest less susceptible to damage by wind, fire, and disease and helps provide a resource that can help fund these restoration activities.

  1. Biomass plants can provide economic benefits through the

    creation or retention of jobs. For example, a 35-megawatt biomass plant would provide about 30 full-time jobs, and potentially another 50 to 100 jobs to collect and transport fuel to the plant. Biomass plants also provide additional economic benefits in terms of taxes paid, supplies purchased, etc.
    Biomass electricity generation can also help reduce the import of other fuels such as natural gas from out of state.

The earliest inhabitants of this region burned wood in their campfires as heat. The forest products and maritime industries began utilizing wood to power steam donkeys, in the late 1800s. Today, lumber mills generate nearly all of their energy using waste from the milling process, and there are currently about 40 biomass plants operating in the state of Washington. Biomass sources currently provide about 3 percent of all energy consumed in the U.S, and about 14 percent of the world’s energy needs.

Depending on the interpretation and regulatory impact, this could severely constrain the future of biomass plants. If the federal government takes a shortsighted approach of looking solely at carbon dioxide emitted from the smokestack, instead of the full carbon cycle, then it will severely discourage the responsible development and utilization of renewable biomass in the future. Burning wood debris for biomass energy production is not only renewable and carbon neutral, but it also burns methane, a greenhouse gas, which would be released if the debris were left to decompose.

These facilities burn the same fuel as a fire place or wood stove, but they employ state-of-the-art emission control technology that must meet federal and state air quality laws and regulations. State and federal agencies are also required to monitor these plants to ensure compliance. Without specific approval from regulatory agencies, they would not be allowed to operate.

State laws requires that forest landowners leave both standing trees and downed wood in harvested areas to provide wildlife habitat and enrich soils. Most of the litterfall, or organic matter is delivered to the forest floor during the forest growing cycle. During tree harvest, biomass fuel harvesters are required to ensure that sufficient woody debris is left to comply with state law.

Forest managers utilize the whole tree, seeking the highest and best use of each part. The highest value end use for wood fiber is generated through traditional manufacturing jobs in the forest products industry, which generate four to 11 times as many jobs using the same quantity of wood fiber to generate energy. The beauty of energy generation is that it can be accomplished using excess woody biomass that is available after traditional use needs are met. Biomass energy plants, especially in the Northwest, utilize wood residuals that are a byproduct of the timber harvesting process, rather than timber that could be made into more profitable products such as furniture, lumber and pulp for paper.

Generally, biomass generation plants burn organic fuel such as wood waste to heat water, which creates steam that runs through a turbine to create electricity. Some biomass energy plants also reuse the steam, once it has passed through the turbine, to provide steam heating. Some plants also use biomass in combination with fossil fuel to produce electricity as a way to cut down on the volume of fossil fuel they consume. Each biomass plant must meet the specific federal, state and local regulations applicable to it, its fuel supply and any impacts, in order to be approved by the regulatory agencies.

Biomass energy is particularly beneficial because it can provide “base load” electricity, meaning that it is available 24/7/365, unlike intermittent sources of energy such as solar or wind that are only available part of the time.

Organic biomass is also the only renewable resource that can be used to create liquid transportation fuels, also known as biofuels.

Washington State University is leading a research project to assess the commercial viability of sustainable aviation fuel production from biomass grown, harvested and refined in Washington, Oregon, Idaho and Montana. WSU has been working with Boeing, the U.S. Air Force, Sea-Tac International Airport and others on aviation biofuels for several years.

Woody biomass can be processed into wood pellets, biochar and other materials. These products can be used in wide applications from helping reduce emissions in coal plants to providing sustainable fuel sources for African farmers and improving soil and water quality. Researchers around the world are studying ways to mass produce biochar that could help everything from African farmers to the fight against climate change.

Biomass already provides a significant share of energy production in the U.S.

  • Biomass is the country’s largest source of domestic renewable energy, supplying about three times as much energy as wind and solar power combined.
  • The more than 100 biomass plants in the country generate 8,500 megawatts of electricity, enough to power 8.5 million homes.
  • Provides 18,000 jobs, many of them in rural communities.
  • Generates $1 billion a year for the nation’s economy.
  • Removes 68.8 million tons of forest debris a year.
  • Diverts 36.2 million tons of urban wood waste from landfills a year.
  • Each biomass plant contributes $8 million to $14 million a year to the local community where it operates, through salaries, purchases and tax revenue. See Office of Energy Efficiency and Renewable Energy for more information.

In the Northwest, biomass electricity is primarily created by the controlled burning of wood waste that otherwise would be dumped in landfills, burned in open air or left to decompose. Most often the wood waste is burned to heat water and create steam, which flows through a turbine to produce electricity.

Generating electricity with biomass provides environmental benefits that make it a preferred alternative to fossil fuels.

Burning fossil fuels such as coal and petroleum adds carbon to the atmosphere that would otherwise remain trapped underground for perpetuity, absent geologic events such as volcanic eruptions or oil seepage.

In contrast, burning biomass releases carbon dioxide that would have been released anyway through decay or wildfire, and is therefore part of the natural carbon cycle. The carbon dioxide released when the wood waste is burned is replaced when forests are replanted and is reabsorbed by growing plants and trees, so there is no net atmospheric carbon dioxide as long as the carbon cycle is in balance. Thus energy produced from biomass is carbon neutral as long as the region practices sustainable forestry.


If we substitute biomass fuels for fossil fuels, we recycle carbon to the atmosphere rather than introducing geologic carbon to the atmosphere – helping reduce the buildup of CO₂.



Washington State law requires replanting of the forest after harvest. Our sustainable forest management creates new fiber supplies to meet future needs and also ensures attention to environmental and biodiversity objectives for the long-term health of the ecosystems in which we operate. On average, three seedlings are planted for each tree harvested. As a result, the carbon storing cycle is continuously renewed.

Washington State law requires replanting within 3 years. On average, Washington forest landowners replant within 18 months, three trees for every one harvested. Sustainably managed forests that are periodically harvested, planted and regrown to produce a continuing series of products and energy fuel actually sequester and offset more cumulative carbon than forests that are left unharvested.


In Washington State, woody biomass is a by-product of the normal forest management harvesting and replanting cycle. Instead of burning piles of forest residue after timber harvests, this underutilized material can be used to produce renewable energy. Forest thinning to improve forest health by reducing fuel loads on eastside dry land forests can provide woody biomass for additional renewable energy feedstocks. Forest thinnings have been identified as the nation’s largest underutilized source of woody biomass.

In the United States, we are growing more trees than we are harvesting. Image source: USDA Forest Service, U.S. Forests Resource Facts and Historical Trends, September 2009.

Forest thinnings have been identified as the nation’s largest underutilized source of woody biomass.


Improved milling efficiency has resulted in production of more lumber and less waste. Foresters are dedicated to gaining the most value for the forest products that they sell. Improvements in technology, science and a skilled workforce have improved milling efficiency, resulting in production of more lumber and less waste. When a tree is harvested, all parts of the tree are used. The lumber is used in carbon-storing building materials and wood products. Pulp and paper are processed from wood chips. Energy is produced from sawmill and harvesting residue in the form of biomass. More than 5,000 different products including resins, glues, cosmetics and food are produced from trees.

Our state has more than a century of experience in improving sustainable forestry practices. We are blessed with abundant wood resources that provide more than 2/3 of all potentially available biomass, including forest residue from timber harvests and forest thinning that improves forest health by reducing fuel loads on eastside dry land forests.

Public policy supports the use of biomass for energy production as reflected in the state’s Renewable Portfolio Standards. In 2006, Washington voters approved Initiative 937 requiring electric utilities to produce at least 15% of their energy using renewable sources such as wind, solar and biomass by 2020. Among these alternatives, biomass stands alone as the only one that can provide sustained power, rather than intermittent electricity from wind or solar that is susceptible to shutting down if optimum conditions don’t exist.

In 2008, the Washington State Legislature adopted new laws creating a schedule for reducing greenhouse gas emissions and increasing clean energy sector jobs. The new statutes specifically recognize that emissions of carbon dioxide from combustion of biomass from fuel wood, waste wood or forestry residuals are not considered a greenhouse gas, as long as the region maintains or increases its ability to sequester carbon dioxide through sustainable forestry.

Engrossed Second Substitute House Bill 2815 (PDF)


Biomass energy generation also provides significant economic benefits, including tens of thousands of jobs, many of them in rural communities, and it reduces our reliance on fossil fuel imports from other countries, which can improve our balance of trade and enhance our national security.

Biomass energy also provides another way to sustain the economic viability of maintaining working forests on the landscape. Today, many of our private forests lands are at risk due to economic factors that provide a higher financial return for developing land rather than keeping it as forest. Increasing the value of the business of forest management by developing new markets such as bio-energy can provide landowners an additional economic return that encourages continued investment in working forests.

As U.S. Agriculture Secretary Tom Vilsack said, “For forest ownership and stewardship to remain viable, it must remain economically rewarding as well for landowners. By generating rural wealth, we can make it possible again for landowners to sustain our forests and our working landscapes.”

Critics of biomass energy generation have generally either misunderstood the science or relied on distortion to demonize it and downplay its benefits. A recent example was the mischaracterization of a study in Massachusetts that some media reported as casting a negative light on biomass energy generation. In response, the study authors issued a clarification noting the mischaracterization and citing the overall benefits of biomass energy.

It is clear that the growing utilization of biomass to generate energy simply adds to the many benefits that are derived from the sustainable use and management of our forests.

The leading international authority on climate change, the Intergovernmental Panel on Climate Change (IPCC), recognizes the significant potential of forests in mitigating climate change. In its fourth Assessment Report, the IPCC states, “a sustainable forest management strategy aimed at maintaining or increasing forest carbon stocks, while producing an annual sustained yield of timber, fiber or energy from the forest will generate the largest sustained mitigation benefit.”