In past years environmentalists used to champion the use
of woody biomass, especially for home wood burners and fireplaces as a natural,
carbon neutral source of home heat. In more recent years the data clearly shows
that woody biomass is not carbon neutral at all since a significant amount of
the carbon from a decomposing tree will be taken up by nearby plants over the
years and decades it decays. It can take decades for a decomposing tree to release
much of its carbon into the atmosphere. When logs or pellets are burned that
carbon is released instantaneously into the atmosphere along with a host of
dangerous pollutants. In several cities around the world the biggest source of
air pollution in the winter is home wood burning. Fortunately,
environmentalists have reversed course on woody biomass with even hardcore
environmentalists like Bill McKibben who once embraced biomass, turning away
from it. Indeed, these days environmentalists are leading the charge against pollution,
greenhouse gas emissions, and environmental justice concerns of biomass.
This post is
not about home wood burning but about the densified woody biomass industry where
forest waste, wood product waste, and hardwood trees, are processed by being
densified into chips and pellets, transported on ships to the U.K. and E.U.
countries to be burned in power plants while getting credited and subsidized as
a form of renewable energy. Now it is true that wood pellets produce less
emissions than logs when burned so pellet stoves are indeed less polluting and
less carbon intense than logs. However, the energy it takes to process the wood
into pellets subtracts from the pollution and carbon intensity advantages of
pellets over logs. A certain percentage of the densified woody biomass for export
comes directly from cutting hardwood trees. This portion also increases carbon
emissions through deforestation. The Energy Information Administration (EIA) began
reporting more in depth on densified biomass in 2016. Now there is a monthly densified
biomass report.
Source: Energy Information Administration
An environmental
group, the Rachel Carson Council, published a scathing report in 2019 about the
environmental and environmental justice concerns of the densified biomass
industry, focused on the industry in North Carolina and the company Enviva.
They noted that the Southeast and North Carolina have the largest concentration
of clear-cutting logging for the wood pellet industry. The wood pellet for
export industry began to take off in the mid-2000’s as EU countries and the UK
were looking for alternatives to coal. Since coal plants can be relatively easy
to adapt to burning wood pellets and pelletized wood does have less combustion
emissions than coal it was considered to be a “green” solution. However, more
recent changes to carbon accounting and life-cycle pollution emissions have
shown that this is not a green solution at all. Citing a 2015 study by the NRDC
they note that several new studies “have found that burning wood pellets for
fuel releases as much as, or even more, carbon dioxide per unit of energy than
coal.” Whether this is true depends on several factors such as wood sources
for pellet production, time frame, and post-harvest forest management practices.
Greater demand for wood pellets has resulted in higher percentages of clear-cut
hardwood forests supplying the industry. That really hurts the carbon
accounting. Clear-cutting is de facto deforestation. It has led to flooding and
erosion issues in North Carolina. It can also reduce biodiversity if not done
correctly.
Source: Clear Cut: Wood Pellet Production, the Destruction of Forests, and the Case for Environmental Justice. Rachel Carson Institute. 2019. Clear Cut: Wood Pellet Production, the Destruction of Forests, and the Case for Environmental Justice (sec.gov)
Source: Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice. Rachel Carson Institute. 2019. Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice (sec.gov)
Wood chips are
processed first by drying at very high temperatures, then ground into a fine
powder, then compressed into pellets. Processing and burning of wood pellets
produce volatile organic compounds (VOCs), nitrogen oxides, carbon monoxide (CO),
and particulate matter (PM). Up until
2018 these facilities were not required to have pollution controls in North Carolina.
The Rachel Carson Council report notes that there have been many complaints
about pollution from the industrial drying facilities and that several of the
facilities are very near what are considered to be environmental justice
communities. Other environmental issues include several reports of smoldering
wood piles and the NRDC reported that “Between 2014 and 2018, local
residents reported fires and explosions at eight of the country’s 15 largest
wood pellet manufacturing facilities.” Apparently, local dust (ie. particulate
matter) is also a major issue.
Source: Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice. Rachel Carson Institute. 2019. Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice (sec.gov)
Drax Power
Station in Northern England converted its generating units from coal to
densified biomass in 2018, earning large government subsidies and tax
incentives for converting to “renewable” power. While biomass can be considered
to be renewable on a long time scale (it takes decades to replace a logged tree)
it is not sustainable or green by any measure. The UK does not account for the deforestation,
processing, and delivery of the pellets in its greenhouse gas inventory. The
idea that burning the wood pellets produces 85% less greenhouse gases than
burning coal is a really a joke. The NRDC calls it scientifically indefensible.
This is of course because combustion emissions are only a small percentage of
life cycle emissions for exported pelletized wood.
The vast
majority of wood pellet production in the U.S. and Canada is for export. In
2016 82% of wood pellets were exported and 15% of total wood pellet production,
or 405,900 tons, came from logging of hardwood trees. In 2021 the percentage of
produced pellets exported was still at 82%. U.S. pellet production quadrupled
between 2012 and 2016. From 2016 to 2021 it appears that U.S. pellet production
increased more than another 30%, As total exports have increased significantly so
has total amount of exports from logging of hardwoods. As in burning coal,
burning wood creates ash. Pellets produce less ash than wood logs, having a
higher rate of combustion. Home pellet stoves burn at 78% efficiency compared
to wood stoves which burn at 54% efficiency. For comparison natural gas and
propane unvented heaters for homes burn at over 99% efficiency and produce no
ash.
Source: Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice. Rachel Carson Institute. 2019. Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice (sec.gov)
Source: Energy Information Administration
Drax Wood Pellet Plant in Mississippi Routinely Exceeds
Annual Air Pollution Limits
More recently, a
wood pellet production facility in Mississippi operated by the Drax Group, part
of the UK company that owns Drax Power Station, has been the subject of
environmental justice scrutiny. Local residents have been complaining about air
pollution and noise pollution at night. They have demanded air quality monitors
and less night-time operation. They have been battling the plant since it opened
in 2016. Production has ticked up since the invasion of Ukraine and Europe and
the UK’s rush to find energy cheaper than the costly oil and gas in 2022. NBC
News reports:
“In 2020, the Mississippi Department of Environmental
Quality fined Drax $2.5 million for violating its permit’s annual limits on the
release of volatile organic compounds. Drax said the company has taken the
appropriate steps to come into compliance with volatile organic compound limits.”
“Outside Mississippi, Drax agreed to $3.2 million in
state penalties in Louisiana just last year for air pollution violations,
though it did not admit any wrongdoing.”
Around 7% of the
U.K.’s electricity comes from the Drax Power Station. The company, which also
produces hydroelectric power and power from pumped storage hydro, showed decent
profits in 2022 like many energy companies. However, without government subsidies
Drax would struggle to be profitable, according to their financial reports.
In Conclusion
The bottom line
for this post is that densified biomass, due to its life cycle carbon
emissions, the time it takes to re-generate forests, and its significant air
quality concerns, should not be considered a viable climate solution. If all pelletized
wood, rather than 80-85%, came from wood waste, that would be an improvement for
carbon accounting. If the pellet production plants were to get better air
quality monitoring, pollution abatement equipment, and better siting, then that
would be an improvement for pollution concerns, environmental justice concerns,
and nuisance concerns. If the U.K. and the E.U. would lower subsidization of
the industry and focus on other fuel sources including natural gas, then the
industry would not continue to grow as it has over the past decade.
References:
A
Mississippi Community takes on a U.K. energy giant over pollution concerns. NBC
News. August 6, 2023. A
Mississippi community takes on a U.K. energy giant over pollution concerns
(nbcnews.com)
Southeast
U.S. Wood Pellet Plants Exporting to Europe. SELC_WoodPelletExportMap_2022_0908_maptable.pdf
(southernenvironment.org)
Drax:
Subsidies for power giant questioned as annual profits soar. Sky News. February
23, 2023. Drax:
Subsidies for power giant questioned as annual profits soar | Climate News |
Sky News
No,
Burning Wood Fuels Is Not Climate-Friendly. Natural Resources Defense Council.
Jodi Helmer. March 8, 2022. No,
Burning Wood Fuels Is Not Climate-Friendly (nrdc.org)
Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice. Rachel Carson Institute. 2019. Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice (sec.gov)
EIA:
Densified biomass fuel production at 860,000 tons in April. Erin Voegele. Biomass
Magazine. EIA:
Densified biomass fuel production at 860,000 tons in April |
Biomassmagazine.com
Densified
Biomass Fuel (ie. Wood Pellets): Usage Distribution and Environmental/Climate
Impacts. Kent C. Stewart. Blue Dragon Energy Blog, February 28, 2017. Blue
Dragon Energy Blog: Densified Biomass Fuel (ie. Wood Pellets): Usage
Distribution and Environmental/Climate Impacts
Densified
Biomass Fuel Report. Connor Murphy, Operations Lead Specialist, EIA, for Pellet
Fuels Institute Annual Conference. June 23rd, 2022. Densified
Biomass Fuel Report (memberclicks.net)
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