Risks from geological storage of CO2 primarily result from the
consequences of unintended leakage from the storage formation that
might can range between short-term potentially large leakages and
long-term, more diffuse leakages, onshore and offshore storage
settings. Risk assessment for CO2 storage is the process that
examines and evaluates the potential for adverse health, safety and
environmental effects on human health, the environment, and
potentially other receptors resulting from CO2 exposure and leakage
of injected or displaced fluids via wells, faults, fractures, and
seismic events. The identification of potential leakage pathways is
integrated with a MMV (Measurement, Monitoring and Verification)
plan. Risk assessment is used to ensure the safety and
acceptability of geological storage. It involves determining both
the consequences and likelihood of an event. Risk mitigation is the
planning for and implementation of contingency plans, should the
need arise, to remediate adverse impacts. A good monitoring and
mitigation plan will decrease the risk and uncertainty associated
with many potential consequences.
RiskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event is defined as a function of the probability of an event that causes harm and its consequence, i.e., "riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event = probability × impact or consequences". In general, overall riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event can be considered as the sum of the products of individual riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event impacts and probabilities, although it is necessary to express the various risks in the same unit (e.g. financial) while risks can be various in nature (human life, leakage(in CO2 storage) The escape of injected fluid from the storage formation to the atmosphere or water column rate, financial loss, etc). In addition, considering overall riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event might not be relevant and considering a series of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event levels might be more appropriate.For CO2Carbon dioxide geological 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%), the main issue is adverse impacts that might result from a potential loss ofstorage(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%) integrity leading to unplanned CO2Carbon dioxide migrationThe movement of fluids in reservoir rocks out of the confining zone. Other types of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event must also be considered such as geomechanical effects, water flow changes, etc. potential consequences are related to public safety and health, environmental (ecosystem) safety, greenhouse gasGas in the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%) that absorbs and emits infrared radiation emitted by the Earth’s surface, the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%), and clouds; thus, trapping heat within the surface-troposphere system. e.g. water vapour (H2O), carbon dioxide (CO2Carbon dioxide), nitrous oxide (N2O), methane (CH4), ozone (O3), sulfur hexafluoride (SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs) emissions to the atmosphereThe layer of gases surrounding the earth; the gases are mainly nitrogen (78%) and oxygen (around 21%), interference with other uses of the subsoil (e.g. water and hydrocarbons), ecEuropean Commissiononomic viability of the project (e.g. financial loss for investors or insurers) and public acceptance. Fig. 6-1 (EPA, 20082008 - USEPAVulnerability Evaluation Framework for Geologic Sequestration of Carbon Dioxidesee more) shows a conceptual framework of vulnerability evaluation for geological 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%) of carbon dioxide.
Operators and regulators have to determine an acceptable level of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event for 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. To establish a reference baseline for acceptable levels of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event, it may be useful to apply metrics which allow ranking the different risks, and compare for instance the health, safety and environmental (HSEHealth, safety and environment) potential risks related to the 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 projects with potential risks arising from other large-scale public/private infrastructure developments (dams, railways, airports, etc.) or analogue activities (oil and gas exploration, natural gasGas stored underground; It consists largely of methane, but can also contain other hydrocarbons, water, hydrogen sulphide and carbon dioxide, these other substances are separated before the methane is put into a pipeline or tanker 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%), acid gasAny gas mixture that turns to an acid when dissolved in water (normally refers to H2S + CO2 from sour gas) disposal, etc.). Of course, all these processes act on different time scales that have also to be accounted for. In particular, CO2Carbon dioxide escape 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%) reservoirA subsurface body of rock with sufficient porosityMeasure for the amount of pore spaceSpace between rock or sediment grains that can contain fluids in a rock and permeabilityAbility to flow or transmit fluids through a porous solid such as rock to store and transmit fluids might be assumed to occur over an extended time scale (centuries to millennia) that has to be considered in each riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event 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 (DNV, 20102010 - DNVCO2QUALSTORE - Guideline for selection and qualification of sites and projects for geological storage of CO2see more). A first common riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event criterion is that risks associated with an activity should not be disproportionate to the benefits. Although risks associated with properly managed CCSCarbon dioxide Capture and Storage projects are expected to be very low, the riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event perceived by the public may be higher and benefits regarding climate change impacts and energy security may be difficult for the public to relate to. A second basic principle for setting riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event criteria is that an activity should not impose Risks that can "reasonably" be avoided. In general, the riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event can always be reduced further by implementation of additional safeguards, but at the price of a higher cost. Defining an acceptable level of riskConcept that denotes the product of the probability of a hazard and the subsequent consequence of the associated event is, therefore, closely related to the viability of the project, the cost of implementation of preventive safeguards and the cost of possible corrective measures (DNV, 20102010 - DNVCO2QUALSTORE - Guideline for selection and qualification of sites and projects for geological storage of CO2see more).
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Fig. 6-1: Vulnerability Evaluation Framework (VEF) for geological 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%) of carbon dioxide (EPA, 20082008 - USEPAVulnerability Evaluation Framework for Geologic Sequestration of Carbon Dioxidesee more). |