Memorandum from Professor Stuart Haszeldine,
UK Energy Research Centre
Increased CO2 emissions from economic
activity are leading to climate warming and acidification of the
upper ocean. Mitigating these effects raise unprecedented challenges
in engineering the habitability of our planet. The potential advantages
of CCS for the UK are outlined. Future sources of oil, coal, and
especially the vulnerability of gas, are discussed. The benefits
of deep geological CCS in EOR, depleted gasfields, and aquifers
are outlined. Particular highlights are placed on problems of
CO2 retention in the deep subsurface for required timescales.
Government issues of: Value, Ownership, Monitoring, and Regulation
or Licensing are critical inhibitors to any large-scale development
of CCS. Opportunities for some middle-scale CCS onshore on the
UK are outlined.
1. Why Carbon Capture and Storage for the
All serious predictions indicate that during
the next 20 years the UK, and the world, will be using more fossil
fuel than in the last 20. This will produce carbon dioxideand
the UK is on course to miss its national 20% reduction targets
in 2010 by 34 million tons per year, out of a total of some 500Mt/yr.
Carbon Capture and Storage (CCS) offers particular advantages
on an intermediate timescale, which can provide options to renewables
or nuclear. Key advantages include: rapid deployment based on
existing technology, flexible generation, diverse fuel sources,
UK expertise and employment. CCS provides an opportunity for a
solution using, or adapting, existing technology, to help the
transition to a new low-carbon, economy, whilst enabling high-technology
employment in the process. The UK is very well placed to develop
and exploit CCS, as there is well-developed fossil fuel power
industry, world-class expertise in offshore surveying, geology
and engineering, combined with accessibility of the world's best-known
sedimentary basins to act as storage sites.
2. Concepts of CCS
The concepts, technology and geology of CCS
are explained in many publications. A short version is briefing
note 238 by POST http://www.parliament.uk/parliamentary_offices/post/pubs2005.cfm.
The most authoritative worldwide being a newly-published (September
2005) Special Report by the Intergovernmental Panel on Climate
Change http://www.ipcc.ch/ An impartial summary of international
research information is http://www.co2captureandstorage.info/.
A technology-based summary including CCS for the UK is published
(April 2005) by the DTI Carbon Abatement Technology http://www.dti.gov.uk/energy/coal/cfft/catstrategy.shtml
A shorter summary of CCS, combined with an assessment of UK business
opportunities, is provided (September 2005) by Scottish Enterprise
A summary of current UK University research in CCS is at http://www.co2storage.org.uk/
The European Union has decided to work to a policy of maintaining
atmospheric CO2 at or below 550 ppm. CCS is expected
to form a strand for major research, technology and development
funding in FP7.
3. Wordwide Drivers for CCS: Climate and Oceans
Most European, and many USA, scientists are
convinced that there is a link between levels of atmospheric CO2
and world surface temperatures http://www.ipcc.ch/. It is less-well
appreciated that increased CO2 leads to ocean acidification,
with poorly known consequences for life in shallow seas around
the UK http://www.royalsoc.ac.uk/document.asp?id=3249. The
UK Government Chief scientist is well-known to hold the strong
opinion that climate change is the greatest threat facing the
human world. The urgency for reducing the rate and total volume
of emission of CO2 is far greater than the rate at
which energy use is changing.
4. Why is the UK Important?
4.1 Much of the fundamental proposal for
CCS, and its evaluation in a UK context has undertaken by the
British Geological Survey, during the 1990's. Most geological
data ultimately derives from this research group. An independent
submission is being made to the Select Committee by the BGS.
4.2 It is clear that the UK has a world-class
opportunity to use CCS. From hydrocarbon exploration, we have
unrivalled knowledge of our offshore geology. These are some of
the worlds best-known and most accessible sediment basins, and
contain both depleted oil and gas fields and deep aquifers of
saline water. The pores in such sediments can hold at least 70
years production of carbon dioxide produced by all European power
stationssome estimates state 500 years. Natural carbon
dioxide occurrences in the UK offshore show that safe natural
storage can be measured in millions of yearsnot just the
10,000 years required to mitigate climate or ocean acidification.
4.3 The UK has an opportunity to establish
a worldwide lead in CCS technology, and in service skills such
as licensing, regulation, monitoring, and project management
4.4 However, several technological problems
may exist for engineered storage, and still need further assurance
(see 9 below).
5. Future Fuel Sources: Coal, Gas and Oil
5.1 One purpose of CCS is to enable continued
use of fossil fuels in UK power generation. These can be coal,
gas, oil, or biofuel mixtures sourced from diverse geographical
and political origins. Such diversity provides a security of supply,
and is not overly dependent on the fluctuations in the market
for one fuel.
5.2 Evidence on an overview of coal use
and power station technology will be submitted by the UKCCSC.
Coal worldwide is generally regarded as having hundreds of years
of reserves, with stable prices having existed until 2004 http://www.investis.com/bp_acc_ia/stat_review/htdocs/reports/report_22.html
5.3 UK oil reserves beneath the North Sea
are about 50% depleted, so that extensive, and increasing, imports
can be anticipated. The quantity and timescale of depletion depends
partly on the price of oil, and any deferment of decommissioning
is financially valuable to both industry licensees, and to the
Treasury by deferment of tax relief. Enhanced Oil Recovery can
assist with some deferment (see 7 below). There is active debate
concerning the possible decline of world oil reserves http://www.odac-info.org/,
or the security of supply for decades http://www.investis.com/bp_acc_ia/stat_review/htdocs/reports/report_5.html.
5.4 Gas supply from the southern North Sea
is now well into decline, and will effectively be exhausted by
2010, with minimal possibility for enhanced production (unlike
Enhanced Oil Recovery). After 2010 about 50% of current UK requirements
could be met from other gas areas of the UK offshore and the remainder
will be imported by pipeline from Norway and the EU, or marine
tanker LNG. However in the 20 year timescale, the world resources
of gas may be dominated by Russia and its Gazprom super-giant
company (which already claims to hold 20% of world reserves).
Russia can dominate the supply to Europe and the UK. The UK currently
holds reserves of only 14 days normal gas supply, in contrast
to the European average of 50 days (http://www.oilandgas.org.uk/issues/gas/
p7, p13, Appendix 2).
6. UK Government and Research Issues
In the UK there is an urgent need for a Government
lead on issues such as (below) :
EOR incentives, financial regime
or reduced tax on extra oil produced;
long term ownership of carbon dioxide;
technological and safety standards;
costs and EUETS clean power
incentives similar to "conventional" renewables
legal licensing or permitting regime
for storage sites;
novel CCS opportunities
timescales of deployment, and public
Many of these need further research, in UK Universities,
Institutes, or Industry.
7.1 Some of the most promising initial developments
for CCS may exploit Enhanced Oil Recoverythat can inject
carbon dioxide to produce 10 percent more oil from existing fields.
But this will only work with suitably engineered platforms. An
extra 900 to 2,000 million barrels of UK oil production can also
store 700 million tons of carbon dioxide.
7.2 A group led by BP and Scottish and Southern
Energy has plans to convert natural gas into hydrogen and carbon
dioxide at Peterhead power station, then pump 1.3Mt CO2/yr
liquefied carbon dioxide to deep storage offshore in the Miller
oilfield, which will produce an additional 40 Million barrels
of oil. The hydrogen will be burned in a modified gas turbine
power plant, to generate 350 MW of electricity with near-to-zero
carbon emissions. This will be a world first, if running costs
can be met for the 15-20 year timescale. There are a group of
other high CO2 oilfields adjacent to Miller in the
UK offshore, and formal or financial encouragement of their Operators
could lead to add-on EOR via the BP CO2 pipeline.
7.3 Miller is a crucial CCS opportunity
for the UK, and it is hard to over-emphasise the unique opportunity
provided by the combination in sequence of: oilfield, pipeline,
equipment, power station, willing companies, and timing. If this
opportunity is missed, it is hard to see another such combination
on the UKCS. Miller can act as a crucial full-scale demonstration
of CCS suitable for EOR, as a bridge to add-on EOR in neighbouring
fields, and as learning for aquifer storage.
7.4 Scottish Enterprise (2005) calculates
that limiting carbon dioxide with CCS electricity will be two
to four times cheaper than the current renewables obligations
based on ROC.
7.5 BP, as the Operator of Miller appears
to require some long-term incentive for the operating expense
of CO2 use during EOR. Previous evaluations of EOR
using the Forties field, or the Gullfaks field have foundered
on finance. Incentives could take the form of tax breaks on capital
cost, or could also be lower tax rates on oil produced by EOR.
The UK Government needs to make a commitment to enable suitable
8. Long-Term Ownership
A significant unknown is the long-term ownership
of stored CO2. It is difficult to expect a commercial
company to maintain ownership for more than a few decades into
the future. Therefore the State may need to be the ultimate guarantor.
It is possible (but unknown), that stored CO2 may eventually
become a resource, rather than a waste product. For example CO2
could become a feedstock for chemical industries; or it may eventually
prove possible to engineer bacteria which are known to feed off
CO2 plus hydrogen, to feed off CO2 plus
water, or CO2 plus sewage, to produce methanewhich
is then useful as an energy source. The UK Government needs to
make a commitment on long-term ownership and long-term liability.
9. Technology and Safety of CCS in Oil and
Gas Fields and Aquifers
9.1 There are many positive points in favour
of CCS in geological storage. However the present writer also
considers that there are several under-researched and under-solved
problems. The extent to which these problems need to be solved,
will depend on the Regulatory framework into which CCS is placed
in the EU and UK.
9.2 Borehole Leakage is usually a key concern.
The main risk for CCS leakage is through the borehole used to
emplace the stored gas. After abandonment, such boreholes are
usually sealed with a specialist Portland-style cement. However
it is known that carbon dioxide reacts with such oilfield cements
on timescales of decades, and their effectiveness is greatly decreased.
Research is underway, in several commercial organisations, to
develop more durable cements. Effective cements should be feasible
to develop within a few years, but do not yet appear to have been
demonstrated. A possibility arises that commercial companies may
develop storage sites, and store carbon dioxide below groundbut
that the cement seals to boreholes last only tens of years after
the company licence has terminated. If the State owns the stored
gas at that time, the State may be liable for continued maintenance
of the boreholes. This issue will potentially affect all pre-existing
boreholes contacted by CO2 dissolved in water, not
just those used to inject CO2. In a typical offshore
hydrocarbon field, this may be 30 boreholes. In saline aquifer
storage there may be fewer pre-existing boreholes, but their locations
may be poorly knownparticularly for onshore locationsand
any leakage will need to be remediated by normal oilfield techniques.
9.3 Monitoring of CCS is proposed to be
undertaken by oil-industry seismic reflection techniques. These
are undoubtedly well-established, and can be deployed to image
liquid CO2. However, such techniques need further
work to enable prediction of any fracturing of the top seal to
a storage site, during the increased pressures necessary for CO2
injection. It is important that seismic is realised to have fundamental
limits on the resolution of thickness of rock layers in subsurface
storagetypically 25 metres would be optimistic. This means
that significant volumes of CO2 may be hard to detectwith
implications for tracking leakage, and for validating volumes
injected for tax credits. Most importantly, the seismic technique
is not at all useful for detecting CO2 once this has
dissolved in pore water filling the reservoir. Additional work
is needed on adapting existing complementary geophysical techniques,
such as electrical resistivity, which are capable of detecting
9.4 Tracers of CO2 are likely
to be useful for safety, and to be economically important. If
a leak of CO2 is detected, the gas itself holds little
information as to its origin. It may not even be possible to discern
if a gas is natural, or is a leak from a storage site. This could
be important for safety liability, and for validating tax credit
claims. It is simple, in principle, to add exotic tracers, which
can fingerprint individual batches of CO2, even if
these are injected into the same disposal site. Exactly which
tracers, what concentration, and how these perform, during subsurface
mixing and fluid movement, is still under active research. The
types of tracer may also depend on the settingparticularly
the spacing between boreholes. This is because the migration speed
of tracers may differ from the CO2 fluid. The UK should
explicitly consider enforced fingerprinting of injected gases
by means of artificially added tracers.
9.5 CO2 injection volumes predicted,
are very poorly understood into depleted oil or gas fields, and
especially in saline aquifers. Estimates range by factors of 10
to 100. More research is needed to predict the volume of CO2
capable of injection into anticipated types of geological sites.
This will reduce the range of uncertainty, and enable improved
planning of pipeline networks, or numbers and locations of storage
sites needed through time.
10.1 Many barriers to CCS are considered
to be financial, so that industries and the EU both aim to reduce
carbon dioxide capture costs to less than £20-30 per ton
before 2010. Storage costs of less than £10-20 per ton
CO2 may be offset by EU-ETS purchase of emission permits.
The costs published from pilot CCS projects at SACS and Weyburn
seem to fall in or below this £10-20 range. To enable this,
CCS must be placed firmly within the EU-ETS. At present CO2
sent for geological storage is apparently not eligible within
the EU-ETS scheme, or within the ROC scheme (cf sect 7.4). This
does not provide fair comparability or "level playing field"
with other sources of low-carbon power generation, such as "conventional"
renewables of solar, wind, wave and tide, which in the UK can
be given Renewable Obligation Certificates (ROC) http://www.dti.gov.uk/renewables/renew_2.2.1.htm,
or even nuclear, which can receive support for technology development.
10.2 It is worth remembering that "cost"
may not need to be as cheap as possible, all that is needed is
a value chain which can enable industries to make a profit. For
comparison, the entire offshore exploration and production of
the North Sea has never been the cheapest world option for oil
or gasSaudi Arabia has been, and still is, much cheaper.
11. Licensing and Regulation of Storage
11.1 The approach to be taken by safety
regulation also needs explicit clarification. There are obviously
complications with OSPAR and London conventions, which need to
be agreed. However for the UK, a choice of principle exists between
taking a very strict "precautionary safety" style of
approach as with radioactive waste, or taking a "performance
and licensing" approach, as with oil and gas exploration
11.2 If the "precautionary safety"
approach is taken, that would imply an extremely high level of
certainty in understanding the sub-surface environment for the
next 10,000 years. Such evidence from a Developer of a storage
site is very difficult to defend, to a legal standardas
has been amply demonstrated by radioactive waste investigations
in the UK and other countries.
11.3 Alternatively, if a "performance
and licensing" approach were to be taken then, at commencement
of storage, a Developer would need to show their expectations
and predictions for their storage site. This would be regularly
Monitored (See section 9.3) during the lifetime of the licence.
If prediction and observed performance were good enough, then
the licence would be continued. This is a much easier, and more
pragmatic, approachand can also enable a rapid start of
licensing storage sites.
11.4 A requirement must be for a Developer
to undertake a fully-specified investigation of the baseline geological
conditions, so that perturbations in future can be clearly identified
(cf Tracers section 9.4)
12. Other CCS Opportunities
12.1 Much attention is being given to large-scale
CCS opportunities involving geological deep storage. In the UK,
some examples are listed below of opportunities for smaller-scale
and novel CCS.
12.2 Onshore local boreholes have not been
much investigated. The cost of drilling and of equipment maintenance
is naturally much cheaper onshore, compared to offshore. The UK
also has a diverse geology, with many areas underlain by deep
saline aquifers. For example, it may be possible to develop sites
with individual boreholes for individual industrial sites of cement
works or paper mills, or district schemes of Combined Heat and
Power using fossil fuels. The UK also has a few existing small
power stations fuelled from biomass. Is it possible that such
enterprises could become not just carbon neutral, but "carbon
negative" by capturing CO2 for local disposal
with individual boreholes?
12.3 Co-firing of biomass has begun in several
coal-fired power stations, as a consequence of the Renewables
Obligation. If these power plants are ever retro-fitted for CCS,
or co-firing is adopted in new-build coal plants, then CO2
from this biomass can be captured and stored to result in a negative
12.4 Negative emissions engineering of CO2
with biomass could become much more feasible. Engineered species
of poplar or willow trees are under development, and could be
grown within 10 years Prof G Taylor 2005, www.ukerc.ac.uk) as
energy crops on set-aside land or as forestry. Radical opportunities
will need to be considered, to move towards and exceed a 60% reduction
of UK CO2 emissions by 2050. Fuels of this type can
link to onshore local storage (above).
12.5 Charcoal is used commercially in some
parts of Japan, and by native Brazilians, to enhance soil fertility.
Charcoal fixes about 50% of the carbon from wood, is very slow
to degrade, and well-preserved examples are known to be 300 million
years old http://www.accstrategy.org/abstracts/ogawaokimoritakahashi.html.
Basically, charcoal can lock-up carbon for hundreds or thousands
of years. Minimal work has been undertaken to assess a UK application,
although it can be calculated that millions of tons Carbon could
be sequestered into soil worldwide using this method.
13.1 The timescale of to commence CCS deployment
can be matched to the timescale of UK CO2 targets (sect
1). Even with the Miller project (Sect 7.2), the current reductions
of CO2 are likely to be much too small to meet these
targets. Much more urgent assessment, and decisions are needed
on several fronts. Firstly, to incentivise further EOR in the
Miller area (maybe another 4Mt CO2/yr). Secondly, to
convert or build new UK fossil fired generating plant. For example,
UK manufacturer Mitsui Babcock states that there is potential
to retro-fit CO2 capture facilities to supercritical
boilers of large coal plant (0.5 Mt CO2/yr each), at
costs of £120M per 600Mwe, 12 months outage time and delivering
CO2 at £12/ton. The size, and timescale, of the
problem means that radical step-changes are required urgentlyor
part-closure of fossil fuel generation may be required to meet
CO2 emissions targets.
13.2 There appears to be a lack of widespread
dialogue between power companies, utilities, and oil companies.
Individual companies are persistently interested, but a much wider
engagement is needed. There is little public information, to help
form perceptions and opinionswhich will be especially important
for onshore projects. UKERC and associated institutions may be
able to broker such issues.
CCS can make a major contribution to reducing
CO2 emissions from fossil fuel in power generation,
for the UK and worldwide. This is extremely urgent, and should
not wait until 2020, because the effects of catastrophic climate
change are already apparent, and the UK is not meetings its CO2
targets. A diversity of fuel options are possible with CCS. Technology
for power generation CCS is available, but has not yet been joined
together in a co-ordinated demonstration. Solving existing technology
gaps is significant, but seems achievable. A commercial development
in the North Sea, headed by BP, is likely to be the first in offshore-onshore
link in the world to undertake this, and could be operational
by 2009. The UK has a world-class opportunity to build on
its expertise and employment in offshore engineering. The UK Government
still has to provide urgent clarification and policy on: market
incentives for CCS (until inclusion within EU-ETS is negotiated,
and ETS caps are a tight enough to require widespread CCS), long
term ownership, standards for monitoring, standards for licensing
and standards for site performance during operation and after
closure. Novel CCS applications can also be investigated in cheaper
UK settings onshore.
18 Stuart Haszeldine is a geologist with 20 years
research experience of the offshore oil and gas industry. He is
also one of a handful of UK academics with current research experience
of geological disposal of radioactive waste. He is co-Director
of the Scottish Centre for Carbon Capture and Storage, a co-Leader
of the UKCCSC research consortium, and a member of the Future
Sources of Energy theme in the UK Energy Research Centre. This
Centre is funded by the UK Research Councils, and aims to provide
impartial, evidence based, advice and information on UK energy