OxyFuel combustion is a key technology for the efficient separation of CO2 from combustion processes. While OxyFuel combustion technology for anthracite and lignite fired power plants leads to CO2 reduction, the combination of this technology with alternative (CO2 neutral) fuels from renewable sources has the potential to deliver "negative emissions" through the long-term removal of carbon from the biogenic cycle (Bioenergy with Carbon Capture and Storage-BECCS).
OxyFuel uses a synthetic mixture of O2 and recycled exhaust gas where the O2 content may be varied. Recycled exhaust gas is used to replace the nitrogen content in the combustion air. The output of the combustion is a CO2-rich flue gas which is best suited for capture and storage (CCS). The oxygen added is an additional degree of freedom in operation of the combustion which allows improved operation especially for low calorific fuels such as sewage sludge; in this way the use of additional fuels such as heavy fuel oil can be omitted.