Prerequisite for a climate-sparing coal-firedpower plantwith CO₂ capture and storage

please click to enlargeFor the environmentally friendly power station planned by RWE, CO₂ storage in former gas deposits, but also in deep geological formations (saline formations: salt-water-filled spaces in sedimentary rock), is being developed and its feasibility checked in parallel with power-plant technology. The development of power plant and storage facility is inseparably linked. In this respect, RWE is currently one of the few companies worldwide to be developing the entire process chain – from power generation via transportation by pipeline all the way to storage – on an industrial scale. 

In parallel to the solution of technical issues, there are standards, legal bases and implementing regulations for storing CO₂ to be created – this is where politicians and the authorities in particular are called upon to generate innovation-friendly conditions for Germany as an industrial location. The European legal framework has been in place since 23/04/2009 in the CCS Directive.
   
The total storage volume 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 348 million t per year (as of 2008) 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.
 

Our project plan for the development of CO₂ storage provides for three work phases:

Phase 1:

• Stock-taking and pre-selection (screening)

• Assessment and feasibility study for selected locations 

Phase 2:

• Exploration of the locations (2D and 3D seismics, and exploratory wells);
• Selection of a suitable depository;
• Implementing the approval procedure.  

Phase 3:  

• Extending the selected storage facility by drilling wells;  
• Erecting above-ground facilities;  

• Connecting to the CO₂ climate-protection pipeline.

  
  We are currently in phase 2.   

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. In the meantime, we can fall back on plenty of data and information.
In Europe, CO₂ 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 will, now and in the years to come, be a particularly interesting spot on the globe. Or, to be more precise: the earth beneath Ketzin. This is because of the innumerable pores in the reed sandstone at a depth of 700 metres that are used today to permanently store the CO₂. In Ketzin, 60,000 tons of CO₂ will be stored. This is roughly equivalent to the CO₂ emissions from 30,000 cars in one year. 

Tests deep down 

Our object in the European joint project "CO₂SINK" as well as in follow-up projects: to find out how the greenhouse gas can be injected safely and on a large scale into deep rock formations. If the vision of an environmentally friendly power plant 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 CO₂ storage onshore in saline rock layers. This reduces CO₂ emissions into the atmosphere and creates a basis of confidence for future projects involving geological CO₂ storage. This is why, with RWE's support, up to 74 tons of CO₂ per day have been sent underground since June 2008. The injected CO₂ has food quality, as used in drinks. Measuring equipment follows the subterranean CO₂ distribution and provides valuable information on the dispersion behaviour of the carbon dioxide. 

You want to know more? Please find more information on this topic in our infotheque.