The workshop was arranged by Bellona and Member of Parliament Claude Turmes, and focused on the possibilities of CO₂ storage in relation to the production of clean hydrogen. Bellona had invited expert J. Michael Austrell from INCO2 to lecture on the CENS project (CO₂ for Enhanced oil recovery in the North Sea).

The CENS project is owned by ELSAM, Denmark’s largest producer of electrical power, and Kinder Morgan, a US energy company with vast experience in CO₂ transport. The project is aiming to prepare for a CO₂ infrastructure in the North Sea.

Vast experience in the US
In the US the experience with CO₂ injection is extensive, and CO₂ has been used in the oil industry for almost 40 years for Enhanced Oil Recovery (EOR). The primary goal has never been to store CO₂, but to take advantage of its ability to increase oil production.

For this reason CO₂ occurring in natural underground deposits has been primarily used. This is transported to oilfields where it is injected as a supercritical liquid in order to pressure up more oil. The largest CO₂ pipeline network in the US is almost 1500 km long. The pipeline in the US is in a comparable scale to what is needed in the North Sea.

CO₂ storage started in the US in the seventies because production started to drop and the oil prices were increasing. This situation is now taking place in the North Sea in relation to the oil production. The drop in oil production in the UK started two years ago, and is expected in the Norwegian sector within two years time.

Photo: Michael Austell og Carl W. Hustad

Can save fragile areas
Austell said that when pumping oil only 20-25% of the content in the field is produced in the first round. Then water is injected into the field to get up an additional 15-20% under secondary production. If CO₂ is used as a third step one can pump up 6-15% of what originally was in the field. Austell says this means a 10-30% increase in the overall oil production fro a field. This could lead to more vulnerable areas being spared from oil drilling.

Today it is common to use natural gas to maintain pressure in the wells in the North Sea. Nearly half of the natural gas pumped up in the Norwegian sector is pumped back into the wells. A considerable part of this will not be possible to regain, he claims.

CO₂ equivalent to 2% of Norway’s GHG emissions already stored
ELSAM is the owner of modern coal driven power plants in Denmark. These have an expected lifespan of 25-35 more years, and will continue to pump CO₂ into the atmosphere as long as coal is being burnt. If these emissions are handled one can trap and deposit 90% of the amount of CO₂ created. By handling the CO₂ from two of Denmark’s power plants, one captures half of the emissions required for Denmark to reduce, in order to fulfil their Kyoto-protocol.

It is not only CO₂ from combustion that is important to store. Just as important is the CO₂ that naturally is coming up from the oil- and gas wells. On the Sleipner-field in the North Sea, Statoil deposits annually ca. one million ton CO₂. Simple maths shows that this is equivalent to 2% of Norway’s GHG emissions, and between a fourth and a third of what Norway must reduce before 2010.

Easier transition to renewable sources
Even if CO2 leads to increased oil production, it does not add up if a value on avoiding CO₂ 2 emissions is not set. Austell mentions the Norwegian CO₂ 2 tax as one instrument to value the sequestered CO₂2. The CENS project is of the opinion that the value of avoiding CO₂ 2 emissions needs to be 20 – 25$ pr. ton, before CO₂ 2 for EOR is financially sound.

Austell closed his lecture by saying CO₂ 2 capture and storage is a tool to use while we wait for renewable systems to be built, and as long as we burn oil and coal. Austell estimates this to go on for another 25-35 years from existing facilities, but he says others are of the opinion that we will use coal long after this. The hydrogen society will evolve through first decarbonising fossil fuels that will require the storage of CO₂ 2 in geologic formations like oil and gas fields, he says. But once the hydrogen and CO₂ 2 infrastructures are built, the transition to renewable sources directly producing hydrogen will be much easier.