Thermal power generation must meet both economic imperatives and increasingly stringent environmental protection criteria. Combined cycles fuelled by natural gas or fuel oil offer very high energy yields (well over 50%) and very low pollutant emissions, but consume fuels whose estimated reserves are low and whose long-term cost is uncertain.
On the contrary, the abundant coal reserves scattered around the world and their lower cost mean that, in the long term, coal can be used to generate electricity. Conventional coal combustion systems generally offer average performance in terms of efficiency and environmental protection, or require additional equipment (flue gas desulphurization, etc.).
Integrated gasification combined cycle (IGCC) transforms coal into a clean, usable fuel for a combined cycle, instead of burning it directly. This technology makes it possible to benefit from the intrinsic advantages of gas-fired combined cycles, but using a less noble fuel: virtually all coals, biomass, petroleum cokes, high-viscosity fuels (HVF), orimulsion, etc., can be used. In particular, the IGCC can burn fuels of lesser quality (high sulphur, chlorine or ash content) while complying with current and forthcoming standards for limiting pollutant emissions, without the need for additional installation.