K E I T H S P E N C E

HEALTH AND SAFETY RISKS OF CARBON CAPTURE,

TRANSPORT & STORAGE

WHAT IS HEALTH AND SAFETY?

• Occupational safety and health

• Primarily covers the management of personal health & safety i.e. the safety, health & welfare of people engaged in work or employment

• Good management systems also address process safety issues

• Process safety

• Focuses at more of a system level on preventing fires, explosions & accidental chemical releases in chemical process facilities or other facilities dealing with hazardous materials

• Prevention of major accident events

• A major accident event (MAE) is an event connected with a facility, including a natural event, having the potential to cause multiple fatalities of persons at or near the facility

WHY HEALTH & SAFETY IS IMPORTANT FOR CCS

• Protection human health and safety

• Maintaining “license to operate” – increase

stakeholder/community confidence that CCS is reliable & safe

• Facilitating cost-effective, timely deployment – safety

promotes quality outcomes

• Protection of ecosystems

• Protection of underground sources of drinking water and other

natural resources

Transport

20%

Industry

26%

Buildings

8%

Other

6%

Agriculture

1%

Power

39% CCS is the only option available

to reduce direct emissions from

industrial processes at the large

scale needed in the longer

term.

CCS should play a key role in

curbing CO2 emission from fossil

fuel-based power generation,

potentially reducing the overall

cost of power decarbonisation

by around US$2 trillion by 2050.

Without CCS, reducing CO2 emissions through 2050 in a 2°C world is highly unlikely in industry and at best very expensive in power

(Source: IEA Energy Technology Perspectives, 2012,2014)

CCS PROCESS

Source: CO2CRC

Capture

Transport Storage

• Health and safety must be assessed across all elements of the

CCS process

• also over the project lifecycle from research, planning, design &

construction, operation & maintenance, decommissioning, long

term monitoring & stewardship

RISK MANAGEMENT CYCLE

Identify major

accident

hazards

Risk assessment

Identify key risk

treatment

measures

Reduce the

risks to

acceptable

level

Set

performance

requirements

Performance

assurance &

verification

Review &

improve

process

MAJOR ACCIDENT HAZARDS

• Identification of hazards at all stages of the CCS process

CO2 gathering

& compression

CO2 capture

from diverse emitters

CO2 transport CO2 storage

Integration hazards• Impact of process upsets

• Interface between different operators

• Impact of different organisational cultures

• Impact of different commercial priorities

• Emergency response

• Operating pressure

• CO2 gathering

networks

• Impact of impurities

in CO2 stream

• Supercritical CO2

• Impact of topography

• Impact of distance & time

• Heavily populated areas

• Variability of CO2 stream spec.

• Pipeline corrosion

• Release of CO2 through

pipeline rupture

• Release of CO2 from well failure

• Leakage into aquifers

• Drilling hazards

• Long injection well life

• Multiple land/resource use hazards

• Encroachment of population

post-closure

• Stewardship post closure

• Capture technology

• Impact on population

• BLEVE

• Water use

RISK RANKING TOOL

PeopleSlight injury or health effect

Minor injury or health effect

Major injury or health effect

Permanent disability of fatality

Multiple fatalities

Assets Slight damage Minor damage Moderate damage Major damage Massive damage

Economic 1% of budget 5% of budget 5-10% of budget>10% of budget

>30% of budget

Environment Slight effect Minor effect Moderate effect Major effect Massive effect

Reputation Slight impact Minor impact Moderate impact Major impact Massive impact

Probability Frequency Insignificant Negligible Moderate Extensive Significant

>95%Has happened more than once per year at the location

Almost certain

>65%Has happened at the location or more than once per year in the orgnisation

Likely

>35%Has happened in the organisation or more than once per year in industry

Possible

<35% Heard of in the industry Unlikely

<5% Never heard of in Industry Rare

Severe Tolerability to be endorsed by management - Immediate action required

High Manage to ALARP

Medium Management action required

Low Monitor and manage by routine procedures

Very Low Manage by routine procedures

Like

liho

od

Consequence

SEVERE

V. LOW

LOW

HIGH

MEDIUM

• Risk - combination of Likelihood &

Consequence

• Risks are compared using the risk

matrix – consequence is not just

about safety

• Effectiveness of

mitigations can

also be compared

• Severe/High risks

• mitigate to ALARP

• Take immediate

action

IS CO2 HAZARDOUS?

• Everyday substance in the air we breathe, in drinks etc

• Properties:

• Inflammable, non-toxic, heavier than air

• Uses – fire extinguishers, EOR, food & drink preparation, plant

growth stimulation humane killer many other uses

• But it is hazardous

• dangerous to humans in high concentrations (Immediate Danger

To Life & Health, IDLH, level is 4%)

• reduction in oxygen in breathing air

• effect on other CO2 stream components

• low temperature during rapid decompression

• corrosive effect on metal

MAJOR ACCIDENT EVENTS - CO2

• Lake Nyos, Cameroon 1986

• Nyos is a deep lake high on the flank of an inactive volcano.

• A pocket of magma lies beneath the lake and leaks CO2 into the water, changing it into carbonic acid.

• On 21 August 1986, possibly as the result of a landslide, Lake Nyossuddenly emitted a large cloud of CO2

(estimated 1,600 kT released) which rose at nearly 100 km/h

• The cloud spilled over the northern lip of the lake into adjacent valleys displacing the air and suffocating 1,746 people & 3,500 livestock within 25 km of the lake.

MAJOR ACCIDENT EVENTS - CO2

• Nagylengyel, Hungary 1998

• Naturally-occurring CO2 and H2S was injected into the Nagylengyel oil field as part of an Enhanced Oil Recovery project.

• The incident occurred on well NIT 1079 on 13 November 1998. Routine work was underway to replace a blowout preventer with a Christmas Tree well-head completion. It is likely that the work dislodged a packer seal, allowing CO2 to escape through the well annulus, leading loss of control. The well was controlled after 60 hours.

• No one was injured but 5,000 inhabitants from three adjacent villages, were evacuated.

Outbreak of CO2 escape

CO2 storage facilityAssume ~30mpta onshore CO2 injection300 injection wells, 20 years of injectionRelease frequency – HC gas injector well is ~3 x 10-5/well year

Likelihood of CO2 release over well injection life ~18%

MAJOR ACCIDENT EVENTS - CO2

• Worms, Germany 1988• On the 21 November 1988 there was a catastrophic failure of a vessel

containing liquid CO2 (30 tonnes) at a citrus facility.• The vessel was over-pressured, leading to loss of containment. • A CO2 Boiling Liquid Expanding Vapor Explosion (BLEVE) occurred • The force of the explosion propelled the majority of the vessel into the

Rhine river, ca 300 m away.

• There were three fatalities, eight employees were hospitalised with serious injuries, three months’ lost production and 20 million dollars’ worth of property damage.

• Monchengladbach 2008• 15 tonnes of CO2 accidentally released from a fire extinguishing system

• 107 people intoxicated• 19 people hospitalized• several fell unconscious & would have died if not rescue

RISK ASSESSMENT

• What could happen?

• Consequence - How much? Duration? How far? How bad?

How many people affected?

• Likelihood - how often?

• What is an acceptable level of risk?

RISK RELATED DECISION SUPPORT FRAMEWORK (OIL AND GAS UK, 2014)

Drilling wells

CO2 storage

wells

CO2 TRANSPORT MAJOR ACCIDENT HAZARD – ASSESSMENT EXAMPLE

• CO2 transport is not new - today, >40 Mtpa of CO2 is safely

transported through over 5,800 km of pipeline

• The scale of future infrastructure & its proximity to populated

areas introduce a risk exposure

• What could happen?

• Accidental discharge & dispersion of concentrated CO2

• What causes?

• Corrosion from uptake of humidity

• Over-pressuring pipeline

• Material compatibility (elastomers, polymers)

• Consequence

How much, what duration?

• Brittle & ductile fracture: in-service ductile fractures have propagated up to 300m in natural gas pipelines

• CO2 is to be transported in dense phase (~400x density of CO2 in air), in big diameter pipelines (e.g. 48”) so CO2 “inventory” is significantly increased

Fracture in natural

gas pipeline

CO2 TRANSPORT MAJOR ACCIDENT HAZARD – ASSESSMENT EXAMPLE

• How far?

• CO2 is heavier than air and can accumulate in low topographic points

• Dispersion modelling along pipeline route to estimate distances & concentrations

• How bad? How many people?

• CO2 is dangerous to humans in very high concentrations - IDLH is 4%

• Likelihood?

• has occurred known in the oil and gas industry. But scale and phase of CO2 transport is new.

• What is an acceptable level of risk?

Dispersion modelling& dose contouring

(UK HSE)

Pipeline fracture arrestor

WHAT IS AN ACCEPTABLE LEVEL OF RISK?AS LOW AS REASONABLY PRACTICABLE (ALARP)

• For risk to be ALARP, it must be possible to demonstrate that the cost

involved in reducing the risk further would be grossly disproportionate to

the benefit gained

Unacceptable

Broadly

acceptable

or negligible

Tolerable or

ALARP

Risk not justifiedexcept in exceptionalcircumstances

Tolerable only if risk

reduction is impracticableor if cost grossly

disproportionate to thebenefit gained

No need for detailed effort to demonstrate ALARP

Inc

rea

sin

g in

div

idu

al ri

sk &

soc

ieta

l c

on

ce

rn

HIERARCHY OF CONTROLS

Elimination

Substitution

Engineering

Controls

PPE

Administrative

Controls

Most

effective

Least

effective

Physically eliminate

the hazard

Replace hazard with

processes/methods with

lower risk

Isolate people from

the hazard through

engineering design

Change the way people work –

training, competency, procedures,

permits, maintenance, ER

Protect workers with

personal protective equipment

CO2 TRANSPORT MAJOR ACCIDENT HAZARD EXAMPLE – REDUCE THE RISK

• Fracture of pipelines can be controlled by:

• control of steel toughness to prevent brittle fracture and to control ductile fracture.

• mechanical collar devices (fracture arrestors) that surround the pipe are employed along the pipelines to arrest a propagating fracture

• Consequence of release can be mitigated by route selection away from populated areas & areas of high risk identified by dispersion modelling

• In heavily populated areas, transport CO2

as low pressure, gaseous phase to reduce inventory

Pipeline fracture arrestor

BOW-TIE TECHNIQUE FORHAZARD & RISK MANAGEMENT

HazardThreat

Threat

Threat

Prevention

barriersConsequence

Consequence

Consequence

Escalation

Barriers

Event/

Loss of

control

Prevention: reduce

the likelihood of

the event

Control & recovery:

limit & mitigate

consequences

Event

THE SWISS CHEESE MODEL

• Accidents are rarely attributed to a single cause/failure – there

are usually many contributing factors

• While many layers of defense lie between hazards and

accidents, there are flaws in each layer that, if aligned, can

allow the accident to occur

Latent conditions create breaches in

barriers - poor design, procedures,

decisions, training

CONCLUSIONS

• Studies show no major show stoppers associated with the CCS process

• comparable risk versus distances for gaseous CO2 and natural gas

• Operators have the tools to prevent major incidents so far as is reasonably practicable

• Major hazard laws and regulations require this

• While it is tempting to say that there are many similarities with Oil and Gas, there are many aspects of CCS that are unique and sometimes subtly different (e.g. scale versus impact on basin hydrogeology)

• Piloting CCS technologies & practices at smaller (but industrial) scale mitigates the implementation risks & provides an opportunity to learn while building vital stakeholder/community confidence that CCS is reliable & safe