State-of-the-Art of Monitoring Methods to evaluate Storage Site Performance

 
1. INTRODUCTION
 
2. MONITORING TECHNIQUES
 
3. MONITORING CONCEPTS – STATUS QUO
 
4. SETTING UP A SITE-SPECIFIC MONITORING PLAN
 
5. CONCLUSIONS AND RECOMMENDATIONS
 
6. REFERENCES
 
 
1.1 General considerations and monitoring framework
 
1.2 Potential risks
 
1.3 Potential impacts
 
1.4 Comprehensive monitoring concepts
 
 
1.1.1 Purposes of monitoring
 
» 1.1.2 Subjects of protection
 
 

1.1.2 Subjects of protection

Storage operations may affect various subjects of protection, public and private goods, single or complex objects. The protection of many of these goods is regulated in specific legislation. The EU CCS Directive does not list single subjects of protection. However, protection of the environment and human health is explicitly named in Article 1 on the purpose of the Directive. Consequently monitoring of these and other protected subjects has to be considered. Protected subjects include:

  • Individual human life and health is generally of highest priority (Article 3 of the Universal Declaration of Human Rights; UN, 1948).
  • Monitoring of the ambient air is a precaution for human health at injection sites and inhabited places where leakage risks may be seen. Maximum working place concentrations or exposure limits are defined for many gaseous substances including CO2.
  • As the mitigation of climate change is the overall aim of CO2 geological storage, monitoring of the effectiveness of CO2 storage and leak detection are mandatory for storage operations under the European Eemissions Trading System (cf. EU ETS Directive).
  • Quality of life may be locally affected (e.g. injection facilities in build-up areas may require noise protection and monitoring).
  • Socio-economic stability is a rather abstract good which generally will not require specific monitoring, but can be affected by the overall storage performance, which is judged on the basis of storage monitoring data (e.g. effects on property values or local employment opportunities).
  • Flora and fauna. Individual plant and wildlife species as well as terrestrial and aquatic life communities, especially endangered species, including their habitats, are subject to nature protection laws. monitoring of CO2 storage needs to pay special attention to such protected areas. Aspects of biodiversity and ecosystem value have been included in the decisions about protected areas.
  • Species or ecosystems which are not specifically protected, such as forests, farm animals or agricultural crops are still subject to individual property rights and coould require monitoring depending, e.g. on economic risks.
  • Soils may be legally protected. Apart from being the basis for agriculture, soils fulfil multiple ecological functions. Thus, in many parts of the world, soil conservation is an important issue and soils are subject to legal protection in European countries as well. A European Framework Directive for Soil Protection (2006/0086 (COD); European Commission, 2006a) is in preparation, as part of the implementation of the European Commission's Soil Thematic Strategy (COM (2006) 231; European Commission, 2006b).
  • Landscape. Apart from the installation of surface infrastructure, the operation of underground storage will generally not affect landscape appearance. However, morphological elements of landscapes could be affected in particular cases. The protection, management and planning of landscapes in Europe is promoted by the European Landscape Convention (Council of Europe, 2000) that has been signed and ratified by most member states of the Council of Europe.
  • Protected areas. The installation of surface infrastructure or invasive monitoring (e.g. observation wells, acquisition of 3D seismic data) may be prohibited in protected areas like national parks. Nature reserves are of particular interest because of their outstanding value, e.g. as habitats of endangered species or for scientific, historical and regional reasons or simply due to their beauty, specific character or rarity.
  • Monitoring groundwater aquifers is mandatory under the EU CCS Directive that requires compliance with the EU Groundwater Directive (2006/118/ec) and also the EU Water Framework Directive (2000/60/ec). Annex II part B and Annex III of the EU Groundwater Directive provide practical orientation for groundwater monitoring. One of the monitoring purposes explicitly mentioned in the CCS Directive is detecting significant adverse effects on the surrounding environment, in particular on drinking water. Thus, freshwater aquifers that serve for drinking water production should be monitored to detect potential pollution, before polluted groundwater flow reaches water works so that appropriate preventive or corrective measures can be taken in time.
  • Onshore open water bodies may be used for drinking water production, leisure, aquaculture, public waterways, waste water discharge or aquatic biotopes. All of these forms of utilisation are subject to regulation. Generally, injection of substances requires permits that are bound to strict conditions. Pollution is prosecuted. Thus, monitoring of open water bodies will probably be required by permitting authorities. In addition, it is in the interest of a storage operator to gather water quality information to trace potential consequences of his activities.
  • The sea is an open water body that is protected against pollution as well. In addition to national legislation for coastal waters, international treaties regulate CO2 storage in international waters. CO2 injection into the open water column or on the sea bed is prohibited by the OSPAR Convention (see 3.2.1). Monitoring shall ensure the integrity of marine ecosystems above off-shore storage sites.
  • Natural resources. CO2 geological storage is in competition with other utilisations of the deep underground and it may influence utilisation/exploitation of mineral or energy resources in the vicinity of a storage complex, e.g. hydrocarbon reservoirs, coal seams, natural brine, geothermal fields. Mmonitoring shall demonstrate the integrity of these resources in the neighbourhood of a storage complex. Active mining of resources may even give reason to exclude storage of CO2 in their vicinity, or impose strict monitoring because of health and safety reasons.
  • Cultural heritage or assets in general might be affected by geomechanical reactions of the storage complex and the Earth's surface to CO2 injection. For conservation reasons, some heritage objects are left in the subsurface. Changes of soil properties and the geochemical milieu might affect the integrity of buried artefacts and structures.