Science - April 7, 2011

Imares studies CO2 leaks into the sea

Carbon dioxide storage is not completely without risks. How does it affect marine life?

 Oil fields in the North Sea can be used for the storage of carbon dioxide.
At the Imares location in Den Helder, tens of white tanks filled with water are standing outside.
In six of these tanks, a disaster will take place a few weeks from now. CO2 is leaking systematically in the North Sea environment simulated within these tanks. This setup is the Netherlands' task in a big European research project (RISCS) concerning the risks of underground CO2 storage. Imares - Institute for Marine Resources and Ecosystem Studies - is in charge of the research area concerning the sea.

It's not that we expect leakages to happen, stresses Edwin Foekema, coordinator of this research experiment into the marine environment. 'The technique of injecting gas into the soil has been used for years for the storage of natural gas. It is a tried and tested technique, but you can't say for sure that the chance that something can go wrong is very slim to none. Even if chances are very small, it is still important to see what can happen and to take precautions. This is the big mistake in Barendrecht: by saying that there are no risks at all.'

Surprising effect
Imares allows as much CO2 leaks in the five-cubic-metres big tanks as is needed to create a very acidic environment. 'Normally, there is a pH of 8; we bring this down to 7, 7.5 and 6. That is really a lot and these scenarios are not realistic. But we want to be able to study the risks.' Foekema and his colleagues subsequently examine how the system responds to the injection. 'CO2 is a nutrient for algae, which will grow faster, provided that there are enough of other nutrients present. But algae die when the acidity is too high. Then again, others may benefit. The interaction can lead to a surprising effect.'

The experiment in Den Helder will last for two months. A follow-up may take place to examine how the system recovers when the leak stops. The final report of all European studies into CO2 storage will only be submitted next year. Underground storage, says Foekema, is actually only a 'temporary solution'. The search for sustainable energy supplies should go on without losing any momentum. 'We should not think that just because there are underground reserves of CO2, we can carry on burning fossil fuels like in the old days.

Re:act