Protecting Our Climate by Turning CO2 Into Stone
Authors: Sandra Ó Snæbjörnsdóttir, Katrín
Steinþórsdóttir, Selja Ósk Snorradóttir and Kári Helgason.
Published in Frontiers for Young
biggest task of this century is to reduce the emissions of CO2 into the atmosphere, to slow down climate change. One key
technology is to capture the CO2 from power
plants and factories to prevent it from affecting the climate. But how can we
store this captured CO2 in a safe and permanent manner?
this article, we report on a method that has been demonstrated in Iceland, in
which CO2 is injected deep into the ground and turned into
stone a natural way of dealing with CO2 emissions!
CO2: A CLIMATE CHANGING GREENHOUSE GAS
back on greenhouse gas emissions into the atmosphere is one of the biggest
challenges of the century. For the past 50–100 years, the average temperatures
on Earth have been increasing quickly. In fact, the past 5 years have been the
warmest years in centuries (1). This rapid warming is mainly caused by human
activities, including the burning of fossil fuels for power plants, cars, and
airplanes. Burning fossil fuels releases greenhouse gases, mostly carbon
dioxide (CO2), which in turn increase the greenhouse effect and
lead to rising temperatures.
rise in temperature, known as global warming, increases the number of
wildfires, speeds up the melting of glaciers, and causes rising sea levels. In
addition, global warming leads to more extreme weather events, such as
droughts, storms, and heavy rainfall. The continued emission of greenhouse
gases will cause further warming of the atmosphere and oceans, which will cause
permanent changes in the earth’s climate, increasing the likelihood of severe
impacts on people and ecosystems.
biggest task of this century is to reduce the emission of CO2 into the atmosphere, to help slow down global warming. This means
changing from fossil fuels to renewable energy sources. In addition, we need to
conserve our resources on Earth, plant trees, and restore land that has been
damaged through human activities. But some CO2 emissions are
hard to get rid of, including the CO2 released from
cement and steel factories, for example. There are also places where renewable
energy is not an option and fossil fuels still need to be burned. How is it possible to
minimize such CO2 emissions?
1 - The Carbfix process. CO2 is captured from an emission source, such as power plant or a
factory. The CO2 is then dissolved in water, just as in a soda
machine. This sparkling water is then injected deep underground, where it is
turned to stone through natural processes that involve the metals contained
within certain types of rock.
WAY OF REDUCING EMISSIONS
key technology for reducing emissions is to capture the CO2that is produced by power plants and factories. This prevents the CO2from being released into the atmosphere and limits the effects of
climate change. But where can we store this captured CO2? How can it be put away in a safe and permanent way?
Iceland, a method has been developed that takes this captured CO2 and turns it into stone, deep underground. This might sound like
magic, but it is actually the Earth’s way of getting rid of excess CO2 from the atmosphere: nature turns the CO2 into stone using metals that are present in certain rocks (2). The
best rocks for this process are volcanic rocks, such as basalt and peridotite,
which contain a lot of the metals needed for this reaction. In nature, this is
a slow progress—too slow to prevent the global warming that is currently
affecting the Earth.
Icelandic project called Carbfix speeds up this natural progress. The CO2 is dissolved in water, the same way a soda machine makes sparkling
water (Figure 1). The water with the dissolved CO2 is then pumped
deep into the ground. If this sparkling water is pumped into the right kinds of
rocks, the rocks release metals that mix with the CO2 in the water and turn the CO2 into stone. This
process safely and permanently removes the CO2 from the
atmosphere, since rocks cannot leak out of the ground.
2 In the future, the Carbfix process may be widely
used for capturing CO2 from power plants and factories, or directly
from the atmosphere, and injecting it into the ground - both onshore and
technology is being used at a geothermal power plant in Hellisheidi, Iceland.
Geothermal plants use steam from geothermal fields which contains a fraction of
CO2, and in the process of producing electricity this CO2 is released. The CO2 emitted from the
power plant is dissolved in water in a structure called a scrubbing tower. The
CO2-charged water is then injected into the ground using a device called an
injection well, which reaches over 2,000 m down into the earth. The basalt at
this depth is perfect for this method since it contains the metals needed for
turning CO2 into stone. Currently, about 12,000 tons of CO2 are turned into stone every year at the Hellisheidi geothermal
plant, instead of being released into the atmosphere. This is equivalent to the
annual emissions from about 6,700 cars (3).
the Hellisheidi power plant is the only facility where this technology is being
demonstrated. About 70,000 tons of CO2 have been
injected and turned into stone since the process started in 2014. However,
there are plans for more widespread use of the technology and, in 2021, the
Carbfix process will be applied to a second geothermal plant in Iceland. There
are also other and even more innovative plans for turning CO2 to stone soon.
REMOVING CO2 FROM THE ATMOSPHERE
scientists have predicted that stopping new emissions of CO2 will not be enough to tackle climate change. In the future, we
will need to start removing the CO2 that we have
already emitted into the atmosphere (4). There are several ways to remove CO2 from the atmosphere, including planting trees and restoring the
health of soils that have been contaminated or overused through farming. Since
we need to remove a lot of CO2 as quickly as
possible, we will also need to rely on technology that captures CO2 directly from the atmosphere. This technology is called direct air
capture (DAC) and it is being developed in several places around the globe.
first example of DAC technology, combined with the Carbfix technology, has been
ongoing in Iceland since 2017. The company Climeworks has developed a facility
that has been removing CO2 directly from the atmosphere. The facility draws
in air and filters out the CO2, which is then
dissolved in water, injected into the earth, and turned into stone (5). The
facility can remove about 50 tons of CO2 every year, an
amount roughly equivalent to that removed by about 2,000 trees.
experiment must be done on a much larger scale in the future. A scale-up of the
DAC facility is planned in Iceland in the upcoming years, which will help to
increase the amount of CO2 captured within stone underground. There is,
however, a big task ahead.
THE FUTURE OF REMOVING CO2 FROM THE ATMOSPHERE
you know that the ingredients for turning CO2 to stone include
a source of CO2, volcanic rocks, and water. In some cases, we will
need to transport the CO2 via pipelines or ships to a location where we
can inject it into the right kind of rocks (Figure 2). Volcanic rocks, such as
basalt and peridotite, are very abundant. In fact, basalt is the most common
rock type on the surface of the Earth, covering most of the ocean floor and
about 5% of the continents (Figure 3). The global storage potential of all the
basalt on Earth is larger than the CO2 emissions that
would be produced from burning all fossil fuels on Earth (2). This means we
have plenty of the right kinds of rock to successfully store CO2 in minerals that would otherwise affect our atmosphere. Water can
be scarce in some areas, so scientists are now exploring ways of supplying the
necessary water directly from natural underground reservoirs or using seawater.
3 - Locations where rocks suitable for turning CO2 into stone can be found. Light green indicates the youngest parts
of the oceanic ridges and areas with volcanic rocks that are suitable for
turning CO2 into stone from Carbfix Atlas.
There is a big task ahead in terms of capturing and
storing CO2. In
the coming years, to protect the Earth and human lives, we need to capture and
store CO2 on
a much greater scale. CO2 must be captured from factory emissions, power
plants, and directly from the atmosphere.
The question that remains is how much
we be able to turn into stone, and whether this amount will be enough to
contribute to protecting the Earth and its inhabitants from the dangerous
effects of worsening climate change.
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