CarbonSignal

Economists Ross Garnaut and Nicholas Stern have both hypothesized that carbon capture and sequestration (CCS) technology will be essential if we are to reduce greenhouse emissions without incurring economic ruin. Some experts have criticised their reliance on CCS because an operational plant has not yet been demonstrated, and green groups often refer to CCS as an unwelcome distraction from investment in renewable resources.

A 30MW coal plant in Germany was opened last week at Schwarze Pumpe, which will provide power for a town of 20,000 people at near-zero emissions with a new pilot-scale CCS process.

The plant was built at a cost of 70 million Euros over a period of two years and the company providing the technology, the Vattenfall Group, suggests that a large-scale installation could begin operation as early as 2013.

Vattenfall expects CCS to cut the plant’s efficiency by about 10% (from around 46%), but they expect to recover most of the initial efficiency loss as they learn more and optimise the process.  They predict the economic break-even point for this technology is around 35 Euros per tonne, which may not be far off considering that the current carbon price in Europe is just below 30 Euros per tonne.

It is important to note that the entire power plant at Schwarze Pump is designed specifically for CCS - this is not a process that can simply be connected to the exhaust stack of an existing plant.  Boilers in conventional coal plants use air (78% Nitrogen, 21% oxygen, 1% other) to support combustion, and produce an exhaust gas that contains a high volume fraction of nitrogen, making the CO2 difficult to separate.  The Schwarze Pump plant uses an oxyfuel boiler which will be fueled by pure oxygen and powdered lignite, significantly reducing the volume of exhaust gas and boosting the volume fraction of CO2.  The CO2 will be separated, liquefied in cylinders, and buried underground.