|June 7: Challenges in carbon storage
Capturing and storing CO2 from a powerplant requires an installation that is three times bigger than the plant itself. So says StatoilHydro spokesman Øystein Johannessen, who was involved in a number off CCS projects.
StatoilHydro is one of the few companies that has actually been capturing and storing carbon on a large scale. At the Sleipner offshore gas field, CO2 is separated from the natural gas (containing 9 percent of CO2) and stored in geological layers on site. Normally this CO2 is vented, but a Norwegian law from 1994 introduced a carbon price of 300 NOK (about 40 euros) per tonne of CO2. This created an incentive for StatoilHydro to invest in CCS, a technology they expect to become a 'licence to operate' in the future. At Sleipner, 1 million tonnes of CO2 has been stored each year since 1996.
To capture CO2 from a cold gas flow with a relatively high concentration of the greenhouse gas is one thing. To capture is from flue gases after combustion is yet another thing. StatoilHydro is preparing such a project at the refinery in Mongstad, near Bergen. Johannessen: “They wanted to build a combined heat and power plant (CHP) and the Norwegian authorities said we had to take out the CO2 from the power plant. The green and red government in Norway consists of three parties and the socialist party will walk straight out of government if they would allow building a power plant without CO2 capture.”
“We made an agreement saying we're going to build a technology centre for post combustion CO2 capture, called the TCM (European Technology Centre Mongstad) that is supposed to test chilled ammonia technology and amines-technology. These technologies are going to be tested up to 100 thousand tonnes per year. It's quite a large test centre. The other part was to build a full scale facility for the powerplant but also for point sources at the refinery, like the cracker for example”.
Partners in the CCS test centre are Gas Nova (Norwegian state gas company) and Shell. An investment decision is about to be taken on the research centre. Johannessen expects the technology centre to be started up in 2011/2012.The full scale demo plant is supposed to be operational in 2014, but the company does not see that as realistic. “We don't believe that's possible. We believe 2015 at the earliest.”
A project that has been cancelled because the CO2 capture would simply be too expensive was a 850 mw gas fired powerplant at Tjeldbergodden. StatoilHydro prepared the project together with Shell. It turned out the powerplant would be three times more expensive because of the CCS. The scale of the facilities needed turned out to be gigantic.
“There we were looking at towers of 20 meters diameter and 30 meters high and we needed two of them. That was just the towers. Then you need all the pipelines. These are HUGE facilities. You need three times the size of the powerplant in addition for CCS. Remember the exhaust gas coming out with atmospheric pressure. From a gas fired power plant, it contains only 3 percent of CO2. The rest is water vapour, nitrogen etcetera. But you have to take everything into the columns. That's an enormous amount of flue gas volumes. You need these extremely large towers filled with chemicals. So it's not an easy task.”
Nobody ever mentions it, but it turns out that CCS on industrial scale is prohibitively expensive. Johannessen: “The biggest challenge in CCS is the cost level, no doubt about it. We need to bring down the costs of CCS. We need to improve the energy efficiency of the process and the material costs. You need so much concrete and pipeline. That costs a lot.”
Nevertheless, Johannessen thinks CCS is an option that needs to be developed: “I think it's extremely important that they solve the post combustion CCS, because it's the only option for the existing technologies and when you're building a coal fired plant today it's going to operate for 40 to 50 years. That's not only in Holland. There's one opening up in China every week. We will just have to find a solution for it.”