Global warming, the term used to
describe the rise in the average temperature of Earths
atmosphere, has been noted and assessed since the late
19th century, but it is only in the past 20 years
that the phenomenon has been common knowledge.
The consequences of global
warming are well known and well documented. And now, more than
ever, action is being taken to try to combat it.
There are three main options in
this drive: to use considerably less fossil energy, to switch
to renewable energy, and to correct the balance between
CO2 input and output.
The preferred option, especially
from an environmentalists perspective, is to use less
But as the global population
continues to increase and economies and infrastructure develop,
that appears impossible. Coal, oil and gas are increasingly
used more, are more readily available and are cheaper to
extract than any alternatives.
There is a fundamental need for
energy - and the feedstock is available.
Although renewable energy may be
an answer in the very long term, possibly hundreds of years,
action to lower CO2 emissions must be taken in a
considerably shorter timeframe, which would not allow for this
technologys storage, location and cost requirements to be
To prevent the atmospheric CO2 concentrations from
rising, one option is to put the CO2 back into an
There are three options to store
- Geological Carbon Capture
and Storage (CCS);
- Injection into
Geological CCS (injection of
CO2 into formations), preferably from power plants,
is the most-researched option, but has many drawbacks
associated with location, energy demand, public acceptance and
costs. Most of the current CCS research and attention is given
to this process.
The second theory is to simply
inject the CO2 deep into Earths oceans.
But, as the oceans naturally
circulate and release CO2, this would harm marine
life and is therefore no longer considered a valid
storage occurs in the following form;
Amount (I0E15 kg)
Recoverable fossil fuels
Olivine is the mineral which has
seen the most amount of examination when it comes to
It is more commonly found as
peridotite, which is a combination of olivine and pyroxene.
Various naturally occurring and
residual materials react with CO2 and sustainably
The carbonation of carbon
dioxide via magnesium and calcium-rich minerals such as olivine
and wollastonite permanently disposes of CO2 in a
geologically stable form.
The products formed by
carbonation are thermodynamically stable, and this route is
viable owing to the massive global reserves of suitable
Much of the research into
mineral carbon sequestration has looked at methods of speeding
up the carbonation process, which is inherently slow in natural
conditions, to create an industrially viable system.
Some research suggests that in
order to accelerate the process from years to hours, the
reaction can be performed in a high-pressure/high-temperature
Suitable processing of the
mineral products, through size reduction and thermal or
mechanical activation, has improved carbonation rates.
The resulting carbonated
products provide a useful source of additional revenue, as they
can be used in construction applications or mine
Olivine reacts with
CO2 to form magnesium bicarbonate solutions and
In Earths oceans, this
forms limestone and dolomite caverns, the ultimate storage
facility for CO2.
In industrial installations, the
olivine can be converted to magnesium carbonate and silica.
In formula form:
Mg2SiO4 + 2 CO2 =>
MgCO3 + SiO2.
The end product now has a lower
energy state than the gaseous CO2.
Most of the carbon is stored in
The vast majority of
CO2 is now sequestered in a safe and stable
Is there enough olivine to
tackle global warming?
There are various options to
increase CO2 sequestration capacity:
- Increase the natural
- Replace products;
- Increase the reaction
rate by high temperatures and high pressures.
Due to the properties olivine
holds, one solution would be to mine, mill and spread more of
Global olivine capacity had been
falling due to a combination of operation scale-backs and mine
closures. World capacity in 2008 was assessed at about 9m tpa,
but this has since decreased.
Sibelco, the worlds
leading olivine producer, restarted production at its
400,000-tpa Raubergvik and 1.9m tpa Grubse olivine mines in
Norway in September last year, after a two-year closure.
Production from the Raubergvik
mine was scheduled to be shipped to the US, mainly for foundry
According to an address given in
July 2009, entitled In Situ Mineral Carbonation in
Peridotite and Basalt for CO2 Capture and
Storage, by Peter Kelemen, Jrg Matter and Dave
Goldberg, there is enormous storage capacity in peridotite.
The Oman ophiolite is 70,000
km3 of which 30% is peridotite.
Similar size ophiolites are in
Papua New Guinea, New Caledonia and along the east coast of the
All of these, except
perhaps for the Balkan examples, extend offshore beneath marine
sediments. This is particularly evident where peridotite
outcrops along the shoreline. In general, near-surface mantle
perodotite is present on all continents except perhaps in
Antarctica, and for example in North America the cumulative
volume of several smaller bodies taken together is comparable
to the volume of peridotite in Oman, the key note
Carbonation of olivine is a
relatively new process and was first suggested in a letter to
the Nature journal in 1990, so this research field is
still new and developing.
The first companies to use these
principles are starting to appear and interest has increased
In the UK, National Grid, the
energy network transmittor, agreed to take part in a
competition in 2009 to upgrade some of its transmission system
The plans were to potentially
use 300km of the National Transmission System (NTS) to pipe
CO2 from the central belt to the St Fergus terminal
in Scotland. From there, the CO2 would be
potentially piped offshore for storage.
The move was part of a
competition held by the Department of Energy and Climate Change
(DECC) to demonstrate commercial-scale CCS in the UK. Following
completion of the competition, a contract was promised to be
awarded to a project to realise the proposal.
National Grid submitted its
proposal in April 2009, and regulator Ofgem sought the views of
the industry at this time.
The project wavered and was
taken off the boiler several times, due to funding uncertainty.
This year, the Energy and Climate Change Secretary Ed Davey
launched a new competition.
This competition, named the CCS
Commercialisation Programme, will support commercial scale CCS
with £1bn in capital funding that the government made
While the CO2 is
sequestered in a geological time scale, there is, as yet, no
real discussion about its release, stability and any risks
inherent in this process.
As an alternative to
sequestering CO2, other techniques can be used to
tackle the problems of global warming such as magnesium release
and neutralising acidic soils.
Although this sector is still small, it is growing at
considerable speed and new products are being developed.