Feb. 3, 2025 Update

As crews continue testing and tuning activities at Standing Bear Lake station, visible emissions may be seen. The exhaust tuning, also called Selective Catalytic Reduction (SCR) tuning, resumed again this week, which creates an exhaust that may look yellow, brown or green as each engine is tuned.

The tuning uses a catalyst and a reducing agent (UREA or Diesel Exhaust Fluid [DEF]) to greatly reduce nitrogen oxide (NOx) emissions, ultimately resulting in cleaner exhaust. Once proper tuning is achieved, you shouldn't see any smoke of these colors at Standing Bear Lake Station.