Quantcast
Popular
Photo credit: CAFNR / Flickr

Biomass More Polluting Than Coal, New Study Finds

By Sami Yassa

A pre-eminent think tank in the United Kingdom, Chatham House, issued a seminal report last week challenging a fundamental assumption underlying European renewable energy policy: that burning forest biomass to produce electricity is "carbon neutral." The report, Woody Biomass for Power and Heat: Impacts on the Global Climate, finds that many forms of forest-derived biopower are likely increasing carbon pollution rather than reducing emissions and calls for restrictions on existing government incentives for the biomass industry in the EU.

The context for this analysis is a cross-Atlantic dirty energy boom, fueled by misplaced subsidies intended to promote clean energy. Currently energy companies are cutting U.S. forests and producing wood pellets to export to EU markets, claiming that biomass fuel is clean and renewable. These exports are driven by generous EU renewable energy subsidies that erroneously reward all forest biomass as "carbon-neutral"—equivalent to non-polluting sources like solar and wind energy. In other words, when counting carbon pollution at a biomass power plant, EU regulators treat the discharge from the smokestack as zero carbon, even though biomass combustion releases carbon emissions at levels comparable to fossil fuels.

The Chatham House report is the capstone to a growing body of peer-reviewed scientific analyses—including the UK government's own modeling—that show forest biomass is not carbon neutral. It underscores that in many cases forest biomass produces more emissions than fossil fuels and these emissions persist in the atmosphere for decades.

The report provides exhaustive research and deliberate reasoning to debunk the industry-promoted myths underlying the EU's misplaced carbon-neutrality assumptions. Here are a few of their top-line conclusions and recommendations:

Biomass Plants Pollute at the Smokestack at Levels Comparable to Fossil Fuels.

Since wood has a lower energy content compared with fossil fuels while also having a higher moisture content, its combustion for energy usually emits more carbon per unit of energy produced than fossil fuels. The Chatham House study, citing numbers from the IPCC confirms this fact:

... in most circumstances, comparing technologies of similar ages, the use of woody biomass for energy will release higher levels of emissions than coal and considerably higher levels than gas.

Burning Biomass Produces a "Carbon Debt" Which is Not Automatically Offset by Forest Regrowth.

The report goes on to underscore a fundamental flaw underlying the arguments of biomass proponents: namely, since forests can regenerate over time and sequester carbon in the process, this regrowth balances or offsets the stack emissions produced by burning wood for energy. The report rejects this overly simplistic error and instead stresses that biomass burning creates a "carbon debt"—excess carbon in the atmosphere—and that the intensity and duration of this debt depends on the type of forest biomass burned (for example, whole trees versus logging residues versus mill waste). In sum it confirms the findings of many prior scientific inquiries that not all biomass is created equal and burning whole trees in particular is always detrimental to climate.

The harvesting of whole trees for energy will in almost all circumstances increase net carbon emissions very substantially compared to using fossil fuels. This is because of the loss of future carbon sequestration from the growing trees—particularly from mature trees in old-growth forests, whose rate of carbon absorption can be very high—and of the loss of soil carbon consequent upon the disturbance.

The use of sawmill residues for energy has lower impacts because it involves no additional harvesting; it is waste from other operations of the wood industry. The impact will be most positive for the climate if they are burnt on-site for energy without any associated transport or processing emissions.

While wood pellet manufacturers in the U.S. southeast claim that most of their wood pellets are produced with residues, the report shows that about three quarters of the pellets from the southern U.S. came from whole trees and residues accounted for only a quarter.

Time Scale Matters

These two examples from the study show that when biomass is burned it releases carbon emissions immediately and this carbon debt lasts anywhere from a few years to many decades (often called the "payback period")—depending upon the type of feedstock used. But carbon emissions from burning forest biomass will have real consequences for climate in the near term—and not just some distant future 100 years from now. These near-term "tipping points" include melting glaciers, sea level rise, disruptions to agricultural systems and effects on human health. So only those feedstocks that reduce emissions in the short term will provide climate benefits. The Chatham House study confirms this finding:

Some have argued that the length of the carbon payback period does not matter as long as all emissions are eventually absorbed. This ignores the potential impact in the short term on climate tipping points (a concept for which there is some evidence) and on the world's ability to meet the target set in the 2015 Paris agreement to limit temperature increase to 1.5 C above pre-industrial levels, which requires greenhouse gas emissions to peak in the near term. This suggests that only biomass energy with the shortest carbon payback periods should be eligible for financial and regulatory support.

"Sustainable Forestry" Does Not Mean Carbon Neutrality

Many biomass proponents like to argue that biomass fuel sourced from a region where the net forest growth is positive or where sustainable forestry is practiced—is carbon neutral. Such logic is nonsense. Rates of forest growth simply cannot detect, quantify or reflect the carbon emissions from an individual biomass-burning facility and it does not establish a proper baseline for accounting or a cause-and-effect between the power plant and the region's forests. The Chatham House study flatly debunks this industry myth:

It is often argued that biomass emissions should be considered to be zero at the point of combustion because carbon has been absorbed during the growth of the trees, either because the timber is harvested from a sustainably managed forest, or because forest area as a whole is increasing (at least in Europe and North America).

These arguments are not credible. They ignore what happens to the wood after it is harvested (emissions will be different if the wood is burnt or made into products) and the carbon sequestration forgone from harvesting the trees that if left unharvested would have continued to grow and absorb carbon. The evidence suggests that this is true even for mature trees, which absorb carbon at a faster rate than young trees.

Among the report's many recommendations, three stand out as rejecting the fundamental carbon neutrality assumption underlying the EU's Renewable Energy Directive and restricting financial support only to biomass feedstocks that actually reduce carbon emissions in the short term—mill residues and post-consumer waste.

  • It is not valid to claim that because trees absorb carbon as they grow, the emissions from burning them can be ignored.
  • The provision of financial or regulatory support to biomass energy on the grounds of its contribution to mitigating climate change should be limited only to those feedstocks that reduce carbon emissions over the short term.
  • In practice, this means that support should be restricted to sawmill residues, together with post-consumer waste. Burning slower-decaying forest residues or whole trees means that carbon emissions stay higher for decades than if fossil fuels had been used.

Burning forest biomass is not a climate solution. It often worsens climate change by emitting more carbon than burning coal. These findings have now been corroborated by an established UK institution with a history of independent and rigorous research. It should serve as a wake-up call to policymakers in both the UK and EU that their renewables incentives and subsidies aimed at reducing carbon emissions from power plants are—in the case of forest biomass power—likely having the opposite effect and making our climate problems worse.

Sami Yassa is a senior scientist for the Natural Resources Defense Council.



Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Food
Workers collect salt crystals on Aug. 22 at Aigues-Mortes where the salt pans cover 10,000 hectares. PASCAL GUYOT / AFP / Getty Images

90% of Table Salt Is Contaminated With Mircroplastics

By Julia Conley

A year after researchers at a New York university discovered microplastics present in sea salt thanks to widespread plastic pollution, researchers in South Korea set out to find out how pervasive the problem is—and found that 90 percent of salt brands commonly used in homes around the world contain the tiny pieces of plastic.

Keep reading... Show less
Climate
Japan's cherry blossoms are unexpectedly blooming this autumn. Coniferconifer / Flickr / CC BY 2.0

Cherry Blossoms are Blooming Across Japan. It's October.

Each year, Japan's iconic cherry blossoms herald the arrival of spring. But after a bout of extreme weather, blooms are being reported several months early.

The Japanese weather site Weathernews said it had received more than 350 reports of blossoms throughout the country. The flowers usually appear in March or April.

Keep reading... Show less
Popular
Bloede Dam removal in process. Maryland Department of Natural Resources Fishing and Boating Services / YouTube

4 Exciting Dam-Removal Projects to Watch

By Tara Lohan

For much of the 20th century humans got really good at dam building. Dams—embraced for their flood protection, water storage and electricity generation—drove industry, built cities and helped turn deserts into farms. The United States alone has now amassed more than 90,000 dams, half of which are 25 feet tall or greater.

Keep reading... Show less
Food
FoodPrint helps identify local and seasonal produce with its Seasonal Food Guide. FoodPrint / Facebook

Find Out Your 'Foodprint': New Website Helps You Shop, Cook and Eat More Sustainably

Two days after World Food Day, an innovative nonprofit has launched a website to help you reduce the environmental impact of the food you eat.

FoodPrint, designed by GRACE Communications Foundation, was created to educate consumers about everything that goes into common food items, from farm to fridge, so that they can make sustainable choices.

Keep reading... Show less
Sponsored
Politics
Acting EPA Administrator Andrew Wheeler testified Aug. 1 before the Senate Environment and Public Works Committee. Win McNamee / Getty Images

Acting EPA Head Is Still Unconfirmed After 100+ Days in Position

Andrew Wheeler, the acting administrator of the U.S. Environmental Protection Agency (EPA), might continue to oversee the office without Senate confirmation until President Trump's term is over, according to reports from Bloomberg and the Huffington Post.

The former coal lobbyist has been the temporary EPA boss for more than 100 days ever since his predecessor Scott Pruitt resigned in July after a long list of ethics scandals.

Keep reading... Show less
Popular
Volunteers prepare to take flow measurements on Muddy Creek. Centre County Pennsylvania Senior Environmental Corps / CC BY-ND

How Monitoring Local Water Supplies Can Build Community

By John M. Carroll

Water insecurity is a touchstone for 2018. Our planet isn't running out of water, but various kinds of mismanagement have led to local water crises across the planet, directly threatening millions of people.

Keep reading... Show less
Sponsored
Climate
Inti St Clair / Getty Images

When It Comes to Sustainability, We’re a Society of Distracted Drivers

By Richard Heinberg

Driving is dangerous. In fact, it's about the riskiest activity most of us engage in routinely. It requires one's full attention—and even then, things can sometimes go horribly awry. The brakes fail. Weather turns roads to ice. A driver in the oncoming lane falls asleep. Tragedy ensues. But if we're asleep at the wheel, the likelihood of calamity skyrockets. That's why distracted driving is legally discouraged: no cell phones, no reading newspapers or books, no hanky-panky with the front-seat passenger. If you're caught, there's a hefty fine.

Keep reading... Show less
Climate
Last month's temperatures across land and sea tied with 2017 as the fourth highest for September in the 1880-2018 record. NOAA

2018 Likely to Rank as Fourth-Hottest Year on Record

After a summer of record-breaking heatwaves and devastating wildfires, 2018 is shaping up to be one of the planet's hottest years in recorded history.

From January through September, the average global temperature was 1.39°F above the 20th century average of 57.5°F, making it the fourth warmest year-to-date on record, and only 0.43°F lower than the record-high set in 2016 for the same period, the National Oceanic and Atmospheric Administration ( NOAA) announced Wednesday. NOAA's global temperature dataset record dates back to 1880.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!