oa CO2 Storage– Monitoring of Related Surface Movements from Space - Potential for Central European Land Cover Conditions?

The EU Directive on Carbon Capture and Storage passed EU Parliament in April, 2009. It requests a complex plan for monitoring CO2 storage sites - during operation and many years after operation. Monitoring methods should represent the best available technique for detecting the existence of the CO2 in the underground. The technology should also provide a wide areal spread in order to capture information of the complete storage complex and beyond. Under this aspect, the strong potential of satellite based radarinterferometric monitoring of surface movements related to underground CO2 storage has been demonstrated at the onshore CO2 storage project at In Salah in Algeria. This arid storage site with sparse vegetation offers perfect conditions for the technique. Nevertheless, future CO2 storage sites in Europe are very likely located in areas with stronger vegetated or agricultural land cover. These areas are subject to some challenges regarding the technique due to short term changes in surface conditions - e.g. vegetation growth. The suitability of the method needs thus also to be demonstrated for Central Europe surface conditions to further establish this very promising technology. As a consequence, a project was initiated by the European Space Agency in order to evaluate the impact of different surface conditions by using most sophisticated radar satellite data available. This contribution summarizes the main results: Latest radar satellite data from TerraSAR-X satellite with maximum spatial and temporal resolution have been used for two different field tests. As a first field case, the CO2 storage site operated by BP/Statoil at In Salah in Algeria has been monitored since 2008. Interferometric processing yielded more complex spatial and temporal surface movement information of the area compared to results from conventional radar satellite data. On the other hand, due to lack of operational CO2 storage sites in Central Europe the technique was evaluated for a gas storage site in Germany - mainly covered by forest and agricultural fields: Number of points with surface movement information from space increased with the use of high resolution data from TerraSAR-X satellite. With this higher number of points and also improved sensitivity to smaller surface movements, the suitability of the method under these surface conditions has been demonstrated. As such, it can be stated that the method of spaceborne radarinterferometry should further be considered for a contribution to the monitoring plan requested by the EU Directive.