CO 2 capture and storage in the sea bed. A critical perspective and questions for discussion EU Maritime Days Gijon May 2010 Peter M. Haugan, Geophysical.

CO2 capture and storage in the sea bed.A critical perspective and questions for

discussion

EU Maritime Days Gijon May 2010

Peter M. Haugan, Geophysical Institute,University of Bergen

www.gfi.uib.no

Some provocative statements

1. There are no measurement techniques which could prove that stored CO2 stays in place with sufficient accuracy for verification.

2. There is a real danger of leakage during the storage operation.

3. Subseabed storage sites have small capacity and are expensive to develop and monitor.

4. Obtaining storage permits will take a long time.

If this is right, then CCS will not be a bridge from fossil fuel to renewable energy.

www.gfi.uib.no

Utsira with Tordis and Sleipner

Tordis

Sleipner

Pedersen, UiB

Tordis

Sleipner

Norway ongoing: Injecting 1 Mt CO2/y from natural gas production at Sleipner into Utsira formation in the North Sea since 1996

Vertical and horizontal seismic sections at Sleipner-Utsira sand

Central chimney conduit plus rapid leakage through 1-5 m shale layers

Vertical movement of CO2 from Sleipner in Utsira

Bickle et al 2007 Modelling carbon dioxide accumulation at Sleipner: Implications for underground carbon storage. Earth and Planetary Science Letters 255, 164-176.

Comparing observed (seismic sections) development of thickness versus radius in 9 distinct layers with analytical gravity current dynamics in porous and permeable media.

Layers have started filling gradually. Leaks occur through thin mudstones.Model-data consistency requires either CO2 permeabilities order of magnitude lower than measured on core samples or CO2 layer thickness from seismic areoverestimated –> Possible that CO2 saturation is small and CO2 has escaped.

Depth of Utsira is close to CO2 low density regime

+ high sensitivity to temperature

=>Hard to estimate CO2 in place

Other parts of Utsira are quite clearly in CO2 low density regime and should be avoided; previous capacities over-estimated.

Still Utsira is probably the most suitable formation in the North Sea with high permeability and porosity.

Outreach material: No significant leakageTruth: Large uncertainty on volumes, fluxes

Injection of polluted water from Tordis field into/beneath Utsira 2008: induced fracture and leakage

Later studies (2010) have shown many similar occurrences.

Length:30-40 m

Depth:7 m

Possible leakage monitoring

Above: Shallow seismic (sparker) profile across the Gullfaks field. Courtesy of M. Hovland, Statoil

Below: Acoustic detection. CO2 release experiment conducted by Brewer et al. (GRL, 2006). Courtesy of P.G. Brewer, MBARI

Above: Model from high resolution multibeam echo sounder. (Vertical axis exaggerated five times). Haltenbanken pipeline down to the right. Courtesy of M. Hovland, Statoil

Below: Collection structure for shallow gas (CH4) monitoring at Troll. Courtesy of NGI and IFE

Norwegian Climit-project 2007/2008 ”Subsea Storage of CO2; the marine component” (Alendal et al) literature survey http://www.cmu.uib.no/projects/CO2Marine

North Sea model study of leakage (Blackford et al, MPB 2008)using well tested hydrodynamic model with tides:Small impact relative to that of uptake scenarios

Model details:

Leakage 5 timesSleipner injection

7x7 km gridDissolved CO2

Highly local effectsnot resolved

Blackford, Jones,Proctor and Holt.MPB56 (2008),1461-1468.

Modelling from Kendall, PML, building on Blackford et al (MPB 2008)

When eagerness dominates and scientific basis is not solid

Wishful thinking for long term evolution of fluid – rock interaction?

Figure included in IPCC SRES 2006.

Studies of natural CO2 reservoirs now question these long term effects.

From IPCC SRES CCS, 2006

Will carbon sequestration be significant for 21st century CO2 levels?

Present projects are only order 0.01 Gt C/year, but are increasing, so maybe useful in the intermediate to long term (not short term!)

ORthe projects may turn out to be environmentally unacceptable, unreliable or too slow to provide a bridge, in which case the net effect is probably higher emissions because of false beliefs.

Will carbon sequestration be significant for ocean acidification?

Some local effects from leakage – studies are needed.Most important effect via the resulting net emissions to the

atmosphere.

Some provocative statements

1. There are no measurement techniques which could prove that stored CO2 stays in place with sufficient accuracy for verification.

2. There is a real danger of leakage during the storage operation.

3. Subseabed storage sites have small capacity and are expensive to develop and monitor.

4. Obtaining storage permits will take a long time.

If this is right, then CCS will not be a bridge from fossil fuel to renewable energy.

www.gfi.uib.no

How to assess the mitigation of global warming by carbon capture and ocean/geological storage

Peter M. Haugan and Fortunat Joos

Motivation:• What may be gained from CCS and how do we quantify the

benefits of leaky reservoirs/temporary storage?

Approach:• Generic climate model study• Choose reference scenario and sequestration cases• Generate results and compare different metrics

Peter M. Haugan and Fortunat Joos 2004. Metrics to assess the mitigation of global warming by carbon capture and storage in the ocean and in geological reservoirs. Geophysical Research Letters 31, L18202, doi:10.1029/2004GL020295.

Approach

• Use reduced form carbon cycle climate model in millennium time scale runs: HIgh Latitude Diffusion-Advection (HILDA) ocean model coupled to a 4-box biosphere model and an energy balance model

• Choose stabilization reference scenarios: WRE 550, 450 and 1000• Capture and store 30 % of emissions after a ramp-up period 2010-2035 =>

CCS comes in addition to stabilization, not instead.• Investigate effects of

– Perfect storage PS (no leakage)– Geological storage with 0.01 annual leakage– Geological storage with 0.001 annual leakage– Storage in the ocean at 800m (dissolved)– Storage in the ocean at 3000m (dissolved)

• Include energy penalty of 20% and 5%

Deduce emissions corresponding to the reference (stabilization) scenarios with no carbon storage

Anthropogenic carbon emissions for the WRE450, WRE550, and WRE1000 stabilization scenarios.

Output parameters to look at for storage cases (S):– Atmospheric CO2

– Surface air temperature T– Rate of change of surface air temperature– Global Warming Avoided (GWA):

dtTTt

t

sref )(0

dtTT

dtTT

t

t

ref

t

t

sref

)(

)(

0

0

0

GWA(t) = GWANorm(t) =

Storage effectiveness EFF(t)=GWA(t) / GWAPS(t)

Use model to investigate effects of capture and storage of 30 % of these emissions

(a) atmospheric CO2, (b) global average surface temperature change, (c) rate of global average surface temperature change, and GWA (d) in °C year, (e) in percent of the cumulative warming of the reference case, and (f) relative to the perfect storage case for WRE550.

Impact of geological vs. ocean storage on climate

Maximum rates of change of temperature are not much affected by any of these carbon storage cases, not even the perfect.

Geological storage with 0.01 annual leakage fraction is less effective than shallow ocean storage (800m). Its effectiveness1 for storing 30% of emissions peaks at 15 % and GWA gets negative after 6-700 years.

Geological storage with 0.001 annual leakage fraction has similar performance to deep ocean storage.2

Normalized GWAs for a given storage case tend to collapse to similar values for different reference scenarios.

Reducing energy penalty from 20 to 5 % has limited effect.

1Storage effectiveness EFF(t) is defined here to be the fraction of the GWA obtained relative to that obtained by perfect storage.

2Deep ocean storage in lakes on the seafloor would perform better than directly dissolved because of delayed mixing into the water column.

Density of liquid CO2, seawater, CO2-enriched seawater and CO2 hydrate

Gas

Buoyantliquid

Negativelybuoyantliquid

Ocean issues related to CCS

-> dissolution, spreading, acidification and potential biological damage, communication to atmosphere.

In addition to the options studied so far there are some yet unexplored versions:

- Inject into high salinity brine water in deep depressions, e.g. the Red Sea, or

- Inject into anoxic basins, e.g. the Black Sea.

- Inject in deep sea sediments in the negative buoyancy zone where dense phase CO2 is denser than formation water and hydrates are stable (House et al., 2006)

+ Perhaps others will be found?

An option that may be better but is presently banned (1.2.3&4 in EU directive)

Only the deep ocean (> 3000m) provides cold temperatures and high pressure to make CO2 negatively buoyant.

Favorable hydrate formation; possibly injection into deep sea sediments.

If geological storage falls out of favor for cost or environmental reasons, perhaps deep ocean will come back ?

House et al., 2006