Achieving net-zero
emissions by 2050 on a global scale requires
not only reducing anthropogenic carbon
emissions but also removing the carbon that
has accumulated in the atmosphere since the
Industrial Revolution. In this episode, we
provide an overview of several carbon dioxide
removal or CDR technologies, how they work, their costs, and the associated
challenges with deploying them at the
scales we require. The first question is, how much carbon do we need to remove from the atmosphere to limit global warming to
1.5 degrees Celsius. Climate Now spoke with
Dr. Roger Aines who leads the carbon initiative at the Lawrence Livermore
National Laboratory. One and a half
degrees Celsius is dauntingly difficult to do. In order to do so,
we're going to have to remove a lot of
the CO2 that we've already put there make up for
the fact that we were too slow and the amounts
are staggering. By the middle of the century, 2050 we'll have to remove 10 billion tons per year of
CO2 from the atmosphere. What is 10 billion tons? We produce five billion tons
of oil worldwide in a year. Ten billion tons means
between now and 2050, we have to create this
entirely new industry, whatever it is, to remove something that's twice the size of
today's oil industry. Understanding the scale of the problem and why
it's important, let's discuss some of the most
commonly cited CDR options and their associated costs. We can separate CDR methods
into two categories. Natural carbon things that we want to enhance,
such as forests, soils sequestration,
and mineralization, and those that are more
technologically intensive, such as direct air capture, bioenergy and carbon
capture and storage, otherwise known as BECCS, and underground geological
storage of CO2. Each of these methods comes in multiple varieties and
much of the work on them is still in
the experimental or very early commercial phases. The numbers that we have
in terms of amounts of CO2 sequestered and costs are yet to be proven on
a commercial scale. We include all of our
sources at the end of our videos and in the
transcripts on climatenow.com. You can always go
deeper if you wish. Before continuing,
it's important to note that oceans also play a huge role in absorbing
carbon from the atmosphere. Naturally, the oceans
take an average of 25 percent of what is released annually
into the atmosphere. The way the oceans
and the atmosphere interact is very complex. But what is certain is
that we do not want to increase the amount of
carbon stored in the oceans, as this is contributing to ocean acidification and the
extinction of species. Now, let's break down
our main CDR methods. Forestation refers
to the planting of trees on lands that
are degraded or reconverted land that was once forested but it's now used
for commercial purposes. In the United States, there are an estimated
133 million acres available for reforestation, which means roughly 333
million additional tons of CO2 could be
sequestered annually. Globally, there are 1.67 billion acres of land available
for forest restoration. If these global forestation
efforts were to succeed, study suggests that by 2050 these forests will have
a net potential to store between 0.5 and 3.6 billion
tons of CO2 annually. Compared to the need to remove
10 billion tons annually, this represents in
the very best case about a third of what
we need to be storing. In terms of cost, this is one of the most affordable methods of CDR at $5-$50 a ton
of CO2 sequestered. A 2018 paper in environmental
letters research specifies the differences in
cost-effectiveness could be due to multiple factors
such as yield rates, land prices, transaction costs, and reporting differences. That said, there are several challenges
with deforestation. One of which is
carbon accounting. Methodologies to
accurately measure the CO2 sequestered by forestation
efforts are not standardized and determining the duration
for which trees are able to grow and continue to absorb CO2 and store that CO2, otherwise known as
permanent sequestration, is challenging. Moving on to more
technologically intensive solutions for CDR. One of the most
widely discussed is direct air capture or direct
air capture with storage. A wide range of technologies
are currently being developed to directly capture
CO2 from the ambient air, and their capabilities have the potential to remove between 0.5 and five billion
tons of CO2 annually. In the best-case scenario, we're looking at another
strategy that can handle about half of our
global sequestration needs. However, capturing the CO2 using this type of technology
is very expensive. Dr. Howard Herzog,
a senior engineer at the MIT Energy Initiative and one of the pioneers
of carbon capture and sequestration has
this to say about it. Carbon engineerings
think they can do it for between $1-$300 a ton of CO2. I've done a lot of analysis. I don't think those
numbers are credible, at least not any in
the near future. People ask me what the
range will be in 2030. I give a range of
$600-$1000 a ton of CO2. Even at $600-$1000 a ton CO2 is still maybe cheaper than getting the jet
fuel off the airplane. Defenders of direct air capture emphasize that this is
just the starter cost. As technologies
improve and scale up, they say they have the
potential to go down to $100-$300 per ton. Many experts agree that this CDR method isn't
the most cost-effective. But major oil companies
like Chevron, Shell, and Total have been
willing to invest given the increasing global pressure to be part of the solution. Another CDR method is BECCS, bioenergy with carbon
capture and storage. Bioenergy is derived
from biomass that is converted into electricity
or a liquid fuel. CO2 released in this process is then captured and
stored underground. Natural resource economist, Dr. Matthew Langholtz at the Oak Ridge
National Laboratory, puts into perspective
how much carbon can be stored using BECCS in
the United States. There has been previous
work estimating up to about 700 million
tons potentially of CO2 sequestered annually. Basically using the
near-term resources, you can sequester about
200 million tons per year. If you add energy crops, you can sequester up to
seven million tons per year. Another way to put
it in context is the IPCC pathway too says
that the world might need a billion times due to sequestered per year to achieve carbon-neutral and one
of their scenarios. Here, you could do most
of that from US alone. It's not everything. It's
not enough for the solution, but it could be a key part of the overall
decarbonization solution. To put that into context, 700 million tons per
year is 13 percent of the United States' total
CO2 emissions in 2019. Globally, BECCS can
store an estimated 0.5-5 billion tons CO2 annually. Not only does BECCS have the
potential to remove half of our target 10 billion
tons CO2 annually, but current cost estimates
for this technology put it as low as
$15 per ton CO2, according to the
Global CCS institute. This low cost assumes that the resulting biofuel is used in the most suitable power
plants and that there's easy access to abundant biomass and
underground storage sites. It also assumes
biomass fuel costs that are lower than
the price of coal. On the other hand, the cost of BECCS can go up to $400 per ton CO2 depending on the
biofuel production method. It is also important
to note that since biomass is
largely sourced from special forestry by-products or crops grown specifically
for this purpose, there is little to no risk
that biofuel production will compete with land use
or forestation efforts. Next, we have soil
carbon sequestration. Rich and untilled soil is a highly dense and
natural carbon sink. Studies estimate that at a
depth of just two meters, the Earth's soils currently hold 2,600 billion tons of CO2. How is this possible? Well, soil organic matter traps carbon via several
ecosystem processes, such as photosynthesis, respiration of
microbes and fungi, as well as decomposition
of organic material. However, rates of soil
carbon uptake change with climate and human activity. The equivalent of
175-350 billion tons of carbon dioxide have
been released through the conversion of natural
to agricultural ecosystems. Total losses of soil organic
carbon as a result of land-use changes
account for a third of anthropogenic CO2
in the atmosphere. While these losses
are significant, studies estimate that by 2050, up to five billion tons of CO2 could be sequestered
in soils annually. That's already half of our 2050 global CO2 sequestration needs. Though it's important to note that soil carbon uptake declines after 20-40 years as soils build up to their
maximum potential. To maximize soil
carbon sequestration, a variety of practices
need to be implemented, including low till or no
till crop management, improved planting schedules, and management of
grazing livestock. Estimated cost of making
these changes are between $0-$100 per ton of CO2. Another long-term and
natural solution to CDR is a method known
as mineralization. Here, CO2 reacts
with compounds like magnesium oxide
and calcium oxide found in minerals like olivine, serpentine, and limestone to trap CO2 into a solid state. The end products of these
reactions are environmentally safe and do not require
post-storage monitoring. Today there are
several companies trying to use this method to monetize products made from
the resulting compounds. As you can see in this diagram, by using CO2 as a
feedstock to create a product that is
two-thirds magnetite and one-third amorphous silica, this process can be used to manufacture concrete,
paper, and polymers. The problem is that it's
very difficult to penetrate these industries
from both the cost and supply chain perspective. We cover these issues in a
podcast with the founder of one company involved in these
efforts, Green Minerals. It is estimated
that the cumulative annual production rates of industrial waste materials have a total CO2 uptake capacity of 0.5-1 billion tons per year at a cost as low
as $48 per ton CO2. But a potentially
unlimited amount of CO2 could be stored per year via mineralization in
natural basalt formations, limited only by our ability to get the CO2 to these formations. The cost of this type of
mineralization ranges from $7-$30 per ton. The last component of the
current CDR portfolio involves the geological
storage of carbon. Storage technology is
integral to both BECCS and direct air capture
strategies as it provides a means to store
large amounts of pure CO2. By looking at this diagram, we can see that this is done by taking CO2 captured
at power plants, turning it into
supercritical CO2, transporting it either to onshore or offshore
storage sites, and injecting it into the
ground or deep water. In this image, we
see that there are four available methods
to store the CO2. The methods are injection
into deep salt formations or into unmineable coal beds for
enhanced methane recovery. CO2 can also be used to
enhance carbon, oil, and gas recovery or can
be injected back into depleted oil and gas reservoirs to restore pressure levels. These geological formations are located all around
the planet and have the capacity to store a total of 25,000 billion tons of CO2. The challenge here however
is strategically choosing storage sites and determining the rate at which CO2
can be sequestered. Sequestering carbon in deep
sedimentary basins comes at an estimated cost of
$7-$13 per of ton CO2. The price tag includes the
cost of well drilling, injection, monitoring, maintenance, and other
incidental costs. However, it does not include
any remediation costs should any well leakage or groundwater
contamination occur. Geological storage of CO2 also comes with the risk of
inducing seismic activity, which means the pressure within these wells would need
to be monitored closely. However, the technology and
methods are well understood. The oil industry has been sequestering carbon
dioxide underground since the '70s as a technique
to enhance oil recovery. These six CDR
strategies: forestation, soil carbon sequestration, mineralization,
direct air capture, bioenergy with carbon
capture and storage, and geological storage, only skim the surface of
what's currently out there. Their associated prices and sequestration potential
are also likely to become more certain as
technologies evolve and policies are introduced to
support their development. What cannot be stressed enough is that at the end of the day, the only way we'll reach
net-zero globally by 2050 will be by investing in all of
these CDR technologies. While we focused on the
best-case scenarios in this video which would allow us to store close to 21
billion tons of CO2 annually, worst-case scenario estimates
wouldn't get us even to half of our global
sequestration needs. For a deeper dive
into this topic, check out our full-length
podcast episodes with experts Howard Herzog, Roger Aines, and
Matthew Langholtz, where we dig deeper
into the evolution and the current state of
CDR technologies. To find out more about
each CDR strategy mentioned in this video, check out our
technology video series that will delve
deeper into each one. To sign up for our
new releases and more, visit climatenow.com. Thanks and see you next time.
