Integrated Gasification Combined Cycle (IGCC)

Integrated Gasification Combined Cycle (IGCC) produces electricity by first gasifying coal. Coal is gasified through a controlled shortage of air or oxygen in a pressurised reactor - ‘gasifier’ - to create a syngas.


This syngas – a mixture of hydrogen (H2) and carbon monoxide (CO) – is first cooled and cleaned of impurities such as sulphur, then combusted with air or oxygen to drive a gas turbine. The exhaust gases are heat exchanged with water/steam to generate a superheated steam, which drives a steam turbine.

By adding a ‘shift’ reaction indroducing steam between the cooler and the gas clean-up, additional hydrogen can be produced and the carbon monoxide can be converted to CO2 which can be captured and stored.

IGCC offers efficiencies up to 50%, with a potential of 56% in the future – significantly improving the environmental performance of coal. Pollutant emissions are also significantly reduced – even compared to advanced conventional technologies:
• 33% less NOx
• 75% less SOx
• almost no particulate emissions.
IGCC also uses 30-40% less water than a conventional plant and up to 90% of mercury emissions can be captured (and at a much lower cost than a conventional plant – typically one-tenth of the costs for a conventional plant).

Further developments to improve efficiency and reliability and to reduce costs are ongoing.