Selective Catalytic Reduction (SCR) is the most effective technology currently available for removing the nitrous oxide gases (NOx) that occur naturally when coal, oil, refuse or gas is burned. SCRs used throughout Mirant’s U.S. fleet have consistently achieved between 60-90 percent NOx reduction, depending on technical specs.

Here’s how SCR works: When the fuel (coal, oil, etc.) is burned in the boiler, the resulting flue gas emissions are directed into a reactor. There, ammonia is added and the process creates a chemical reaction that converts the NOx into benign nitrogen and water vapor that can be safely released into the atmosphere through exhaust.

Ammonia may be delivered to the plant as a gas or liquid. To provide a safer alternative to the community, it may also be delivered as urea (a liquid or solid fertilizer). Mirant has chosen to purchase the ammonia in this form.