Research for safe and permanent CO2 storage
The development of climate-friendly power plants and storage facilities is inseparably linked, if the CCS chain is to be successfully closed in future. RWE is supporting projects that investigate carbon storage in depleted gas reservoirs and deep geological formations (saline formations: salt-water-filled spaces in sedimentary rock). The aim of RWE is to participate in the further development of large-scale CCS projects across the entire process chain - from power generation via transportation by pipeline all the way to storage. The implementation of RWE’s own climate-friendly CCS project in Germany failed in 2010 because of insufficient political and legal conditions. Although a German CCS Law (KSpG) has been in force since the summer of 2012, it actually defines only the framework for CCS research projects nut not for large-scale projects. RWE is involved in German and European research and development projects to build up a Europe-wide carbon transportation and storage infrastructure and explore the German carbon storage facility at Ketzin near Berlin, among others.
The total storage volume for CO2 in Germany is estimated by the Federal Institute for Geosciences and Natural Resources (BGR) to some 20 billion tons of CO2 (+/- 8 billion tons). This means: with an assumed CO2 emission of about 340 million t per year (as of 2014) by the German power industry, these storage sites could absorb the CO2 emissions of the German power-plant population for a period of more than 50 years.
Detecting and operating storage sites
Worldwide, possible sites for CO2 storage are being extensively investigated. For many countries, there are cadasters showing suitable storage regions. These cadasters are currently being given a more precise shape. Candidate CO2 storage facilities include deep, salt-water-bearing rock layers (saline formations), as well as former natural-gas and depleted oil deposits. Such depositories can be found both onshore and below the seabed (offshore). European research projects, like "CASTOR", "CO2GeoCapacity","CO2GeoNet","CENS"or "ECCO", have investigated the various options. With RWE participation, the project "CO2EuroPipe" explored the infrastructural connection of CO2 sources with the storage facilities via a transportation network. In the meantime, we can fall back on plenty of data and information. In Europe, CO2 was and is already being injected in deep storage formations at a number of locations. These include, e.g., a natural-gas deposit in concession K 12-B in the Dutch North Sea, the Sleipner field in Norway's North Sea and, with RWE participation, the Snøhvit project in the Barents Sea. In the latter, up to 700,000 t CO2 per year are sent underground. There as well as in the Sleipner field, continuous CO2 storage is comprehensively monitored.
Successful CO2 storage in Germany
Ketzin in Brandenburg, directly before the gates of Berlin. Anyone driving through the streets of this township with 4,000 souls wouldn't suspect it but, for RWE and large sections of the international energy sector, Ketzin has been a particularly interesting spot on the globe for more than 10 years. Or, to be more precise: the rock beneath Ketzin. This is because of the innumerable pores in the reed sandstone at a depth of 640 metres that are used today to permanently store the CO2. If the vision of an environmentally friendly power is to become reality one day, there is no way around carbon-dioxide storage in the earth. The CO2 research in Ketzin extends our knowledge of the theoretical bases and practical processes for subterranean carbon storage onshore in saline rock layers. This reduces CO2 emissions into the atmosphere and can create a basis of confidence for future projects involving geological carbon storage.
Tests deep down
With the scientific support and involvement of RWE, the European joint project “CO2SINK“ (2004-2010) dealing with carbon storage was executed in Ketzin. Here, with RWE’s support, up to 74 tons of CO2 per day have been sent underground since June 2008. The injected CO2 basically has food quality, as used in drinks. In the storage area under Ketzin, the CO2 exists in a dense and in a gaseous phase. From 2010 to 2013, the follow-up project “CO2MAN“ was under way: We investigated how the greenhouse gas can be injected safely and on a large scale into deep rock formations and how the gas behaves underground. In May 2011 more than 1.500 tons of CO2 from Schwarze Pumpe lignite-fired power plant (Lausitz) were stored in Ketzin. Measuring equipment follows the subterranean CO2 distribution and provides valuable information on the dispersion behaviour of the carbon dioxide. By this it could be proved in the project “CO2MAN“* that the storage of CO2 in Germany is safely possible. In Ketzin, about 67.271 tons of CO2 were stored until August of 2013. This is roughly equivalent to the CO2 emissions from 32.000 cars in one year. Meanwhile, the CO2 storage in Ketzin is finished. In the follow-up project COMPLETE** one of the drill holes was filled in July 2015. The other drill holes will be closed by 2017. The storage site is being monitored continuously, for example by recurring 3D seismic measurements, in order to gain important insights for possible future CCS projects.
* The BMBF project CO2MAN was coordinated by the GFZ Potsdam. Further partners were RWE, VNG, Vattenfall, Statoil, Voestalpine, OMV, Dillinger Hütte, Saarstahl, Umweltforschungszentrum Leipzig and the universities of Stuttgart, Jena, Erlangen-Nürnberg and Leipzig.
** The BMBF project COMPLETE is coordinated by the GFZ Potsdam. Further partners are RWE, VNG, Vattenfall, Statoil, OMV, Gassnova and SINTEF.