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Wood Pellet Fuel
A Low Carbon Replacement for Fossil Fuels in the Power and Heating Sectors
(with the necessary condition that the feedstock is sustainably sourced)
William Strauss, PhDNovember 4, 2019
Modern Wood Heat Symposium
Dr. William Strauss, President
Named one of the most influential leaders in the
biomass sector in 2016 and 2017 by Argus Media. Recipient of the 2012
International Excellence in Bioenergy Award.
A leader in the industry for more than two decades.
John Swaan, Pellet Plant Operations
John is a leading expert on pellet plant operations. He is
the founder of Pacific BioEnergy and producer of the
first bulk shipment of wood pellets from North America to
Europe (1998). Recipient of the 2014 International
Founders Award.
Senior Members of the FutureMetrics Team
Annette Bossler, Market Intelligence Expert
Annette provides detailed market intelligence on
renewable energy policies around the world with a
strong focus on Japan. Annette speaks, reads, and writes fluent
Japanese. She was the 2013 recipient of the President’s
Award from the Maine International Trade Center.
Laurenz Schmidt, Technology Specialist
Laurenz is a globally respected expert in
thermodynamics and mass and energy flow dynamics in the renewable energy sector. He reviews and analyzes all advanced pellet technologies.
Yoshinobu Kusano, Japan Policy Advisor
Yoshi is one of the most highly respected
participants in the Japanese biomass sector. He was a key member of
Sumitomo’s pellet trading operations. He provides
valued insights into Japanese policy developments.
The reason that we care about CO2 emissions
If the trend in the chart below is followed, we will release most of the geologic carbon sequestered over hundreds of
millions of years over a span of about 250 years.
Curve is from a simulation by FutureMetrics
250 Years ➔
Two Major Sectors in the Wood Pellet Industry:
Heating
Power (industrial)
The heating markets, in most jurisdictions (not the US), are
helped by carbon taxes on heating oil.
The taxes are explicitly aimed at lowering the use of fossil fuels.
Pellets are not subject to a carbon tax.
The implication is that pellets are a low carbon solution.
After 2020, under current policy, growth in Europe and UK is almost over.
Japan and South Korea are the major new growth markets.
The industrial wood pellet sector is supported by various policies to compensate the power generators for the higher cost of pellet fuel versus coal.
The policies are based on a strategy to lower carbon emissions from the power sector.
In order to receive the support, the utility has to prove that the pellet fuel lowers carbon emissions.
This is done through independent third-party certification schemes that prove that the sources of feedstock for making the pellets are sustainable. (For example: FSC, SFI, PEFC, SBP)
That is, the annual supply of pellet feedstock cannot lower the forest’s inventory across the landscape and therefore cannot lower the stock of
carbon held by the forested lands.
Biogenic carbon contained in forest biomass released to atmosphere.
Biogenic carbon released during energy generation recaptured in new growth on forest landscape.
Unlike geologic carbon (hydrocarbon), forest carbon (carbohydrate) is continuously recycled.
As long as the harvest rate does not exceed the growth rate over the managed landscape, the atmosphere does not experience a net increase in CO2 concentration from use of pellets.
Geologic carbon released across the supply chain.
Diagram courtesy of Jennifer Jenkins, Chief Sustainability
Officer, Enviva
It is a continuous and dynamic
process across the managed landscape
Absolute necessary condition:
Must be equal to or less than want is sequestered.
0
100
200
300
400
500
600
700
800
900kg
CO
2e
/ M
Wh
e
Wood Pellet
Supply ChainCoal
UK 2020 Electricity
Emissions Threshold
TOTAL EMISSIONS BY FUEL WOOD PELLET EMISSIONS BREAKDOWN
-
20
40
60
80
100
120
kg
CO
2e
/ M
Wh
e
Production Transport by Sea
Transport of Feedstock Harvesting and Chipping
Transport to Port Tansport to Power Plant
Storage and Handling Crop Production87% Total CO2 Emission Reduction
Source: supply chain carbon analysis for pellets produced at Enviva Pellets Sampson and shipped to Drax’s 38% efficiency bioelectricity plant in Selby, UK using the current UK biomass carbon accounting methodology, and Weiwei Wang 2015 Environmental Research Letters report
Only the supply chain carbon footprint is accounted for when the power station switching from coal to pellets shows its net reduction in CO2 emissions.
Courtesy of Jennifer Jenkins, Chief
Sustainability Officer, Enviva
Assuming pellets are sourced from managed forests that satisfy the “necessary condition” heating pellets provide a significant reduction in CO2 emissions.
The notion of carbon debt is an artifact of
assumptions about spatial scale and when
to start the clock.
Looking at one plot or even one tree is a flawed
basis for modeling.
Starting the carbon accounting at the moment of
harvest and replanting is a flawed basis for
modeling.
[From a 2013 paper by FutureMetrics that references the Manomet Study]
A serious flaw in research that shows that carbon emissions for wood combustion add to the
stock of atmospheric carbon is the timing of their carbon-cycle assumptions. Many models
begin the story at the moment the wood is harvested.
Most of the studies that show that wood-to-energy adds to the carbon stock of the atmosphere assume a carbon debt is created that has to be repaid by new growth over decades.
The chart on the next slide shows the carbon-cycle for one plot (or even one tree).
Note that the net carbon stock of the atmosphere is reduced over those thirty years as the new growth absorbs carbon. If every ton from that plot is combusted (highly unlikely!), all of that carbon is returned to the atmosphere, but the net outcome will never be higher than the baseline.
Finally, just from the point of view of a viable business model:
Who would build a new pulp mill or pellet mill for hundreds of millions of dollars with the intention of running out of feedstock in a few years? Or with the
intention of the feedstock becoming more expensive every year as it becomes more scarce?
Major capital investments require continuous long-term operations with stable costs.
That means sizing the plant so that its demand for wood does not exceed the sustainable supply and therefore the plant can receive wood every day of the year for decades at costs that
allow profitable operations.
In summary
Wood pellets sourced from forests that are not being depleted in terms of the net stock of wood (and thus
carbon) held in the managed landscape should be a key part of any decarbonization strategy for
both the heating and power sectors.
Thank you
William Strauss
Bill inspecting the BC forest to verify sustainable management practices.
