HEALTH AND SAFETY RISKS OF CARBON CAPTURE, TRANSPORT & STORAGE K E I T H S P E N C E

Transcription

1 HEALTH AND SAFETY RISKS OF CARBON CAPTURE, TRANSPORT & STORAGE K E I T H S P E N C E

2 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

3 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 Without CCS, reducing CO2 emissions through 2050 in a 2 C world is highly unlikely in industry and at best very expensive in power CCS should play a key role in curbing CO 2 emission from fossil fuel-based power generation, potentially reducing the overall cost of power decarbonisation by around US$2 trillion by Agriculture 1% Other 6% Industry 26% Transport 20% Power 39% CCS is the only option available Buildings 8% to reduce direct emissions from industrial processes at the large scale needed in the longer term. (Source: IEA Energy Technology Perspectives, 2012,2014)

4 CCS PROCESS 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 Transport Storage Capture Source: CO2CRC

5 RISK MANAGEMENT CYCLE Review & improve process Identify major accident hazards Risk assessment Performance assurance & verification Reduce the risks to acceptable level Set performance requirements Identify key risk treatment measures

6 MAJOR ACCIDENT HAZARDS Identification of hazards at all stages of the CCS process CO 2 capture from diverse emitters CO 2 gathering & compression CO 2 transport CO 2 storage Capture technology Impact on population BLEVE Water use Operating pressure CO 2 gathering networks Impact of impurities in CO 2 stream Supercritical CO 2 Impact of topography Impact of distance & time Heavily populated areas Variability of CO 2 stream spec. Pipeline corrosion Release of CO 2 through pipeline rupture Integration hazards Impact of process upsets Interface between different operators Impact of different organisational cultures Impact of different commercial priorities Emergency response Release of CO 2 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

7 RISK RANKING TOOL 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 Likelihood People Slight 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% >65% >35% Has happened more than once per year at the location Has happened at the location or more than once per year in the orgnisation Has happened in the organisation or more than once per year in industry Almost certain Likely Possible <35% Heard of in the industry Unlikely Consequence LOW MEDIUM HIGH SEVERE <5% Never heard of in Industry Rare V. LOW Severe High Medium Low Very Low Tolerability to be endorsed by management - Immediate action required Manage to ALARP Management action required Monitor and manage by routine procedures Manage by routine procedures

8 IS CO 2 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 CO 2 stream components low temperature during rapid decompression corrosive effect on metal

9 MAJOR ACCIDENT EVENTS - CO 2 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 CO 2 into the water, changing it into carbonic acid. On 21 August 1986, possibly as the result of a landslide, Lake Nyos suddenly emitted a large cloud of CO 2 (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.

10 MAJOR ACCIDENT EVENTS - CO 2 Nagylengyel, Hungary 1998 Naturally-occurring CO 2 and H 2 S 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 Routine work was underway to replace a blowout preventer with a Christmas Tree wellhead 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 CO 2 escape CO 2 storage facility Assume ~30mpta onshore CO2 injection 300 injection wells, 20 years of injection Release frequency HC gas injector well is ~3 x 10-5 /well year Likelihood of CO 2 release over well injection life ~18%

11 MAJOR ACCIDENT EVENTS - CO 2 Worms, Germany 1988 On the 21 November 1988 there was a catastrophic failure of a vessel containing liquid CO 2 (30 tonnes) at a citrus facility. The vessel was over-pressured, leading to loss of containment. A CO 2 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 tonnes of CO 2 accidentally released from a fire extinguishing system 107 people intoxicated 19 people hospitalized several fell unconscious & would have died if not rescue

12 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?

13 RISK RELATED DECISION SUPPORT FRAMEWORK (OIL AND GAS UK, 2014) Drilling wells CO 2 storage wells

14 CO 2 TRANSPORT MAJOR ACCIDENT HAZARD ASSESSMENT EXAMPLE CO 2 transport is not new - today, >40 Mtpa of CO 2 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 CO 2 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 CO 2 is to be transported in dense phase (~400x density of CO 2 in air), in big diameter pipelines (e.g. 48 ) so CO 2 inventory is significantly increased Fracture in natural gas pipeline

15 CO 2 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 CO 2 transport is new. What is an acceptable level of risk? Dispersion modelling& dose contouring (UK HSE) Pipeline fracture arrestor

16 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 Increasing individual risk & societal concern Unacceptable Tolerable or ALARP Broadly acceptable or negligible Risk not justified except in exceptional circumstances Tolerable only if risk reduction is impracticable or if cost grossly disproportionate to the benefit gained No need for detailed effort to demonstrate ALARP

17 HIERARCHY OF CONTROLS Most effective Elimination Substitution Engineering Controls Administrative Controls 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 Least effective PPE Protect workers with personal protective equipment

18 CO 2 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 CO 2 as low pressure, gaseous phase to reduce inventory Pipeline fracture arrestor

19 BOW-TIE TECHNIQUE FOR HAZARD & RISK MANAGEMENT Threat Prevention barriers Hazard Escalation Barriers Consequence Threat Event/ Loss of control Consequence Threat Prevention: reduce the likelihood of the event Control & recovery: limit & mitigate consequences Consequence

20 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 Event Latent conditions create breaches in barriers - poor design, procedures, decisions, training

21 CONCLUSIONS Studies show no major show stoppers associated with the CCS process comparable risk versus distances for gaseous CO 2 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