The final conference of CO2CARE - CO2 Site Closure Assessment Research - brought together 60 experts from the academic, industrial and regulatory worlds to discuss technologies and procedures for a safe and sustainable closure of geological CO2 storage sites.

The CO2CARE EU project combined experimental laboratory and field research as well as numerical simulations in an integrated approach and tested and developed technologies and methodologies. The result is that the three main requirements of the EU Directive for the transfer of responsibility to the appropriate regulatory body (still to be determined) can be met: modeled behavior conforms with the observed behavior of the injected CO2, there is no detectable leakage, and the storage site is evolving towards a situation of long-term stability.

Though western CO2 emissions have dropped, especially in America where emissions from energy production are the lowest in 20 years, countries that are still classified as 'developing', especially China, India and Brazil, have increased their use of fossil fuels substantially, and so carbon capture and storage
(CCS) technology will continue to be studied as a mechanism for global reduction of CO2 emissions.  

The key component of the CO2CARE project is the site-based research with an international portfolio of nine CO2 storage projects. In addition to Sleipner in Norway and K12-B in the Netherlands, the Ketzin pilot site operated by GFZ is one of three sites for which in the framework of CO2CARE the closure and the transfer of responsibility to the regulatory authority was theoretically developed.

"Our work at the Ketzin site has shown that and how geological CO2 storage on a pilot scale can be done safely and reliably," said Axel Liebscher, project coordinator and head of the Center for Geological Storage (CGS) at the GFZ. "The knowledge gained in the project CO2CARE and newly developed procedures and technologies are a key step forward to implement the requirements of the EU Directive (DIRECTIVE 2009/31/EC) for geological storage of CO2 in national CCS laws and to ensure a safe and sustainable closure of geological CO2 storage sites."

At the Ketzin pilot site the storage of CO2 was terminated in August 2013 after more than 5 years of successful operation. "By now the post-injection phase has begun and the Ketzin pilot site will be the first site which will be closed within a scientific project. The results of the CO2CARE project will be implemented here directly," said Liebscher. "Only if we can also demonstrate the safe and permanent closure of CO2 storage sites in addition to the safe operation, CCS is able to develop its potential."

It may not be so simple. A recent study blamed earthquakes in Texas on CO2 injections.