The concept of scrubbing carbon dioxide from power plant flue gases has been around ever since global warming and climate change became part of our vocabulary. When it quickly became evident that flowing the huge amounts of flue gases from coal-burning power plants through an amine-based scrubber would be totally impractical and expensive, another approach was considered. A better idea would be to gasify the coal to make so-called synthesis gas using oxygen (rather burning with air, thus greatly reducing the amount of flue gas) and then burning the synthesis gas to generate electric power while capturing essentially pure carbon dioxide for sale or storage. These would have to be brand new plants, would cost more, but could be built in areas where large amounts of carbon dioxide could be sold for tertiary recovery in depleted oil fields. The theory sounded good and the Federal Government liked the idea enough to help support an immense pilot project
This brings us to the Kemper plant in Mississippi which recently started up, though not yet on coal. The location was inspired by the fact that it would be built over a huge deposit of lignite (a very low cost, very dirty coal) and not far away from oil fields that could beneficially use large amount of carbon dioxide for tertiary recovery. The DOE had been looking to help fund projects that would successfully demonstrate carbon dioxide recovery from flue gases, but had given up on direct flue gas scrubbing when an old Illinois power plant, rebuilt with amine scrubbing and DOE money, was shuttered. So, Kemper looked like an ideal location to demonstrate the potentially ideal way to capture carbon in concentrated form – though this required building an entire plant from the ground up.
The project has turned out to be far more costly than the originally budgeted $ 2.4 billion. Though not yet in full operation, the plant cost is now up to $ 6.3 billion and it looks more like a petrochemical plant than a power plant as the above graphic from Scientific American magazine shows. And it is not yet operating the coal gasifiers and runs on natural gas for the time being. So, more funds will probably be required before the plant is fully operational.
A similar experience has dogged another flue gas scrubbing prototype at the Boundary Dam plant in Sasketchewan. Similar to Kemper, this plant gives a cost of 11,000 per kilowatt of electric generating capacity, equivalent to Kemper. This translates to an extra cost of 4 cents per kilowatt-hour for consumers, amounting to about a 30 percent increase over the average American power cost.
A number of other worldwide carbon capture projects have been scrapped over the last several years.
And here is another interesting point: When the oil recovered from the carbon dioxide captured at Kemper is burned, carbon dioxide will, of course be emitted from the tail gates of cards and trucks using gasoline made from the recovered oil, thus partly negating the carbon capture of the Kemper coal-fired power plant. On an overall basis, using natural gas with much less carbon emission is probably a more sensible solution than Kemper with tertiary oil recovery, given also the very much higher investment for Kemper versus a new natural gas-based power plant.