MonitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions according to the European CCSCarbon dioxide CaptureThe separation of carbon dioxide from other gases before it is emitted to the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) and Storage Directive has to be based on a riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event. "RiskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event" is generally defined according to ISO31000:2009 as an "effect of uncertainty on objectives". Therein effect means any deviation from the expected; the uncertainty results from a lack of knowledge or understanding about events, consequences, or likelihood. This general definition integrates various conceptions about riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event from specific perspectives and focuses on different objectives, e.g. medical, financial, security or social issues. General concepts of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event basically include:
- the perception that something could happen,
- there is a possibility to influence the outcome (in contrast to fate),
- the probability of something that could happen,
- the consequences if it does happen,
whereby at least one of the possible outcomes is undesired.
A widely accepted riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event definition refers to riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event as the product of an events' probability times its consequences. For practical purposes of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event management, riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event levels may be classified accordingly: An unlikely occurrence of an incident in combination with small consequences describes the lowest riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event (lower left corner; Fig. 1-1), while high probability and hazardous consequences mark highest risks (upper right corner; Fig. 1-1).
| 
Fig. 1-1: Schematic levels of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event classified according to the probability of an incident and its impact |
The riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event levels are often associated with further measures for riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event management and in particular for monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions (Tab. 1-1). High or highest risks would correspond to 'significant riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event', as defined in the EU CCS DirectiveDirective 2009/31/EC of the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide as "a combination of a probability of occurrence of damage and a magnitude of damage that cannot be disregarded without calling into question the purpose of this Directive for the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere site concerned". MonitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions is required for low risks, but also for lowest risks, as riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event levels could change during storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere operation, e.g. the total mass of CO2Carbon dioxide injected will increase with time. Therefore, Article 13 of the EU CCS DirectiveDirective 2009/31/EC of the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide requires monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions for updating the assessment of the safety and integrity of the storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere complex in the short and long-term. If the assessment of risks changes during storage(CO2) A process for retaining captured CO2, so that it does not reach the atmosphere operations, the monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions plan has to be updated (Annex II, EU CCS DirectiveDirective 2009/31/EC of the European Parliament and of the Council of 23 April 2009 on the geological storage of carbon dioxide).
| Tab. 1-1: riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event levels and associated measures for riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event management and monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions. | RiskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event level | Consequences | | highest | unacceptable, not permissible or injectionThe process of using pressure to force fluids down wells stop, corrective measureMeasure taken to correct (remediate) significant irregularities or to prevent or stop leakages of CO2Carbon dioxide from the storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) volume required | | high | actions to reduce consequences or probability | | medium riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event | actions to reduce consequences or probability | | low riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event | acceptable, monitor and be prepared for further measures | | lowest riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event | acceptable, low level monitoringMeasurement and surveillance activities necessary for ensuring safe and reliable operation of a CGS project (storage integrity), and for estimating emission reductions, unless the riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event level changes | |
Only for a few risks, the probability of an incident can be derived directly from observations, e.g. frequency-magnitude relations for earthquakes recorded by regional networks. In most cases, numerical simulations are the only way to quantify the probability of different scenarios for various risks derived from storage(CO2Carbon dioxide) A process for retaining captured CO2Carbon dioxide, so that it does not reach the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) features, events and processes (FEPs). However, the probability of basic assumptions used in the numerical models often cannot be quantified and is only taken into account as model properties or boundary conditions for site-specific or generic riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event assessments. Chadwick et al., 2008, e.g. conclude that an "overall, quantitative assessment of the probability of any particular scenarioA plausible description of the future based on an internally consistent set of assumptions about key relationships and driving forces; note that scenarios are neither predictions nor forecasts occurring is very difficult, particularly for scenarios involving geological FEPs (e.g. fault(geology) A surface at which strata are no longer continuous, but are found displaced leakage(in CO2Carbon dioxide storage) The escape of injected fluid from the storage formationA body of rock of considerable extent with distinctive characteristics that allow geologists to map, describe, and name it to the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) or water column, caprockRock of very low permeability that acts as an upper seal to prevent fluid flow out of a reservoir, failure, etc.)".