Explain the Integrated Gasification Combined Cycle (IGCC) technology and its environmental benefits.

IGCC converts coal or other carbonaceous feedstocks into synthesis gas (syngas) through partial oxidation in a gasifier, then uses the cleaned syngas in a combined cycle power plant. The gasification process enables removal of sulfur, particulates, and mercury before combustion, resulting in significantly lower emissions than conventional coal plants. Pre-combustion carbon capture is more efficient than post-combustion, making IGCC compatible with CCS. The process achieves 40-45% efficiency with potential for polygeneration (producing chemicals alongside power). Challenges include higher capital costs, lower availability, and operational complexity compared to conventional plants.