BioEnergy with
Carbon Capture and Storage, or BECCS includes CCS with ethanol and other liquid
biofuels production, industrial process fueling and co-firing, and wood-burning
power plants. For power plants, it is basically harvesting wood to be burned in
woodburning power plants, capturing and storing the carbon, and re-planting
trees to help mitigate the carbon emissions. Advocates say that life cycle
process can be carbon negative. I am very skeptical about that since it may
take up to a century to replace the carbon sinks taken away to be replenished.
Some of that carbon will also be prevented from being taken up by the soil.
Wood burning is also highly polluting, worse than coal according to several
studies.
The main
argument in support of BECCS as a climate solution, that it can be carbon
negative compared to fossil fuel CCS which can only approximate carbon neutrality,
seems legit on the surface, but there are other considerations. There are both
environmental challenges and technical challenges. I have written in the past
about some of the environmental challenges of harvesting, processing, shipping,
and burning densified
woody biomass, basically wood processed into pellets. My post highlighted both
the significant environmental issues around densified woody biomass and the inefficiency
of the process compared to both coal and natural gas.
Biomass processing
and refining of different types, including as ethanol, produces CO2 in different
processes as shown below. Both industrial processes and energy plant processes
produce CO2 that can be captured. Ethanol refining produces high-purity CO2
that has advantages for optimizing CCS. That is why it has been pursued so
much. The IEA reports that BECCS mitigates only around 2 Mt of biogenic CO2 per
year and most of that is from ethanol plant CCS. IEA also notes:
“Based on projects currently in the early and advanced
stages of deployment, capture on biogenic sources could reach around 60 Mt CO2/yr by 2030, which falls far short of the
approximately 185 Mt CO2/yr captured from biogenic sources by 2030 in the Net
Zero Emissions by 2050 (NZE) Scenario. Targeted support for carbon dioxide
removal (CDR), and BECCS in particular, will be required to translate recent
momentum into operational capacity.”
The IAE thinks
that BECCS can increase by 30 times the current deployment by 2030, just five
years away, while their 2050 NZE scenario requires it to be increased by over
92 times the current deployment! Right now, I doubt that the 30 times increase
in that short timeframe is even feasible. IEA gives lead times for BECCS
projects ranging from 1.5 to 6.5 years with the average being 3.5 years, with 1
to 2 years being a common lead time for ethanol projects. Thus. ethanol CCS
projects will likely continue to dominate BECCS projects. The IEA also notes:
“Around 90% is captured in bioethanol facilities, one
of the lowest-cost BECCS applications due to the high concentration of CO2 in
the process gas stream. The largest operating BECCS project to date is the
Illinois Industrial CCS Project, which has been capturing CO2for permanent
storage in a deep geological formation since 2018. The Red Trail Energy and
Blue Flint bioethanol plants, the second and third in the United States
targeting dedicated storage, came online in 2022 and 2023, respectively. Other small-scale
bioethanol facilities are capturing CO2 in Europe and the United States, but
these either sell the CO2 to greenhouses for yield boosting or use it for
enhanced oil recovery.”
Another issue
for BECCS deployment is development of the transport and storage infrastructure
for CO2. That will likely slow down deployment. The development of industrial
hubs or clusters that share the CO2 infrastructure is one potential solution to
lowering costs, but it will take time to get these projects going and to better
understand their practical challenges as well as their potential benefits. These
projects are still in pilot or demonstration phases and still require
significant subsidization, particularly on the transport and storage side which
require higher upfront investments. In the U.S. the Midwest Carbon Express
project plans to connect 57 bioethanol
plants with a pipeline network across 5 states.
There has been considerable public opposition to CO2 pipelines, and this will likely
slow down the pipeline building process which will slow down the deployment
process. The U.S. announced in February 2024 that $100 million will be invested
in carbon dioxide removal (CDR) projects, which include all CCS projects,
including BECCS.
Biomass
cofiring for electricity production and industrial applications is a current
solution that has been commercialized in pulp and paper mills, cement plants,
and steel blast furnaces. However, cabon capture for those applications is
currently lagging. The IEA graph below compares technology readiness levels.
Some environmentalists prefer BECCS over
fossil fuel CCS since it would not perpetuate the use of fossil fuels. However,
it would take a massive amount of land to take up the slack of fossil fuels
production with less efficient wood. Detractors (like me) would ask if we
really want to pursue burning wood as a climate solution. The concept of “renewable”
biomass is not really a sustainable one since it takes several to many decades to
replace a mature tree. Wikipedia notes:
“Biomass production is subject to a range of
sustainability constraints, such as: scarcity of arable land and fresh water,
loss of biodiversity, competition with food production and deforestation.”
These issues make BECCS even less suitable for developing
countries. No doubt, BECCS projects will increase and offer some carbon
offsetting for developed countries, but I do not believe it will be a
widespread solution or one that makes much of a dent in emissions reduction overall.
The IPPC Sixth Assessment notes:
“Extensive deployment of bioenergy with carbon capture
and storage (BECCS) and afforestation would require larger amounts of
freshwater resources than used by the previous vegetation, altering the water
cycle at regional scales (high confidence) with potential consequences for
downstream uses, biodiversity, and regional climate, depending on prior land
cover, background climate conditions, and scale of deployment (high confidence).”
Thus, it is a
limited solution and one that is not likely to be very significant overall.
Another issue that
limits BECCS suitability is that for the process to be environmentally and
economically optimized, power plants would have to be built close to biomass
sources to limit transport costs and emissions. That limits where the most desirable
BECCS projects can be built.
Perhaps the
most significant issue with BECCS is its thermal inefficiency compared to coal
and natural gas. According to the IEA via Wikipedia:
“…biomass in general is a low-quality fuel. Thermal
conversion of biomass typically has an efficiency of 20-27%. For comparison,
coal-fired plants have an efficiency of about 37%.”
“Low energy conversion efficiency, energy-intensive
biomass supply, combined with the energy required to power the CO2 capture and
storage unit impose energy penalty on the system. This might lead to a low
power generation efficiency.”
The 2019 graph
below from the Rachel Carson Institute shows this issue pretty clearly.
Source:
Clear Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice. Rachel Carson Institute. 2019. sec.gov/files/rules/petitions/2019/ptn4-741-exb.pdf
The bottom line
about BECCS is that it will likely be a limited climate solution.
References:
Maybe
we don’t have to capture so much carbon, study suggests. Justine Calma. The
Verge, June 13, 2024. Maybe we don’t have to capture so
much carbon, study suggests (msn.com)
Bioenergy with carbon capture and storage. Wikipedia. Bioenergy
with carbon capture and storage - Wikipedia
Bioenergy
with Carbon Capture and Storage. International Energy Agency. Last updated April
2024. Bioenergy
with Carbon Capture and Storage - Energy System - IEA
Clear
Cut: Wood Pellet Production, the Destruction of Forests, and the Case for
Environmental Justice. Rachel Carson Institute. 2019. sec.gov/files/rules/petitions/2019/ptn4-741-exb.pdf
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