We can capture carbon, but can we store it?

Next month sees the United Nation’s COP 15 meeting taking place in Copenhagen, Denmark, where world leaders will hopefully hammer out the successor to the Kyoto Protocol. The discussions at this meeting will be wide ranging, exploring all climate mitigation options, including carbon capture and storage (CCS). Although it remains controversial, CCS continues to hit the headlines.

Within the last month, for example, the European Commission proposed six demonstration CCS projects to receive a total of €1 billion ($1.6 billion) in funding. The projects include Powerfuel Power’ Hatfield integrated gasification combined-cycle (IGCC) power plant in the UK, Vattenfall’s Jaenschwalde plant in Germany, with oxyfuel capture technology, and Poland’s Belchatow power station, which will use an advanced amine post combustion capture process.

Furthermore, Finnish utilities Fortum and Teollisuuden Voima Oyj have named Siemens Energy as their capture technology partner for the FINNCAP à‚— Meri-Pori CCS project this month. This demonstration project is anticipated to treat approximately 50 per cent of the flue gas from the 565 MW Meri-Pori power station and capture 90 per cent of the carbon dioxide (CO2)

Another important development was the recent announcement from US utility We Energies that a pilot project utilizing an advanced chilled ammonia process captured more than 90 per cent capture of the CO2 from the flue stream of the coal fired Pleasant Prairie power plant in the US state of Wisconsin.

Finally, Canadian power company TransAlta and Alstom, together with the governments of Canada and Alberta and independent power producer Capital Power, are to construct a large-scale CCS demonstration facility at one of TransAlta’s coal fired generating stations.

What is especially important about this project is that it represents the first large-scale capture project in the world (1 million tonnes of CO2 a year) and is the first to have its own integrated underground storage system.

Without doubt the area of carbon capture is developing rapidly, with many of the world’s major power OEMs developing proprietary capture technology and partnering power producers in demonstration projects. So it appears we can capture CO2 effectively, but what about its long-term storage? Why does this area seem to have less prominence?

Part of the reason may be our assumption that subsurface CO2 injection is already a mature technology. But is this assumption justified? For decades the oil and gas industry has been injecting CO2 for enhanced oil (or gas) recovery. For example, Statoil, Norway’s oil and gas major, has been depositing its CO2 emissions in offshore saline aquifers in its Sleipner gas field since 1986.

Although this experience is valuable because it provides confidence that many aspects of geological storage of carbon can be managed, for CCS to be an effective mitigation technology it must not only provide effective long-term storage but also be able to store this greenhouse gas at a mind-blowing scale of many billions of tonnes per year.

Thus, this begs the question: Is there sufficient space in the Earth’s subsurface to store this CO2? The answer to this question at the moment is quite simply, we don’t know.

Initial estimates indicated abundant capacity, but when more detailed evaluations of specific sites are conducted the results are often less positive. At this year’s COAL-GEN Europe, Grahame Smith, technical head, carbon storage at Senergy Alternative Energy (www.senergyworld.com) gave an excellent reality check on geological carbon storage.

It is clear that much more work needs to be done in this field. One piece of welcome news however, was the recent announcement by the Energy Technologies Institute that it has launched an ambitious à‚£3.5 million ($5.7 million) project to assess the UK’s CO2 storage capacity. It will be interesting to see if or when other countries follow suit.

Kind regards,
Heather Johnstone
Senior Editor

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