Carbon capture

Basin Electric Power Cooperative is to use Powerspan’s carbon dioxide (CO₂) capture technology to demonstrate its viability at the Antelope Valley Station, a coal-based electric power station located near Beulah, North Dakota.

Approximately one million tons of CO₂ will be captured annually from the 120MW slipstream project, making the demonstration among the largest in the world.

The captured CO₂ will be fed into an existing CO₂ compression and pipeline system owned by Basin Electric’s wholly owned subsidiary, Dakota Gasification.

The project is scheduled to move forward in 2009, subject to the successful completion of engineering studies and obtaining of necessary permits and US government incentives.The facility itself is expected to be operational in 2012.

Powerspan’s CO₂ capture process, called "ECO₂" is a post-combustion, regenerative process which uses an ammonia-based solution that captures CO₂ from the flue gas of a power plant and releases it in a form that is ready for further compression, safe transportation, and geological storage.

'The commercial-scale demonstration at the Antelope Valley Station will provide sufficient information to design, build, and guarantee the performance of full-scale ECO₂ systems,' said Powerspan's CEO Frank Alix.

The Antelope Valley Station consists of two coal-based electric generating units, each rated at 450MW. The ECO₂ commercial demonstrator will draw the equivalent of a 120MW slipstream from one of the two units and will be designed to capture 90 per cent of the incoming CO₂. The captured CO₂ would then be delivered by pipe to the existing compressor station at Dakota Gasification’s adjacent Synfuels Plant and injected into Dakota Gasification’s 205-mile pipeline system.

The technology is suitable for retrofit to the existing coal-based, electric power stations as well as for new coal-based plants. The CO₂ capture takes place after the nitrogen oxides (NOx), sulphur dioxide (SO₂), mercury and fine particulate matter are captured. Once the CO₂ is captured, the ammonia-based solution is regenerated to release CO₂ and ammonia. The ammonia is recovered and sent back to the scrubbing process, and the CO₂ is in a form that is ready for geological storage.

Ammonia is not consumed in the scrubbing process, and no separate by-product is created.