What is Wet Stacking?
Wet stacking is a phenomenon that occurs in diesel generators when they operate for long periods at low loads, usually below 30% of their rated capacity. Under these conditions, the engine does not reach the proper combustion temperature, leading to unburned fuel, soot buildup, and oil deposits in the exhaust system.
Main Causes of Wet Stacking
Constant low loads: the engine never reaches optimal working temperature.
Incomplete combustion: diesel fuel does not burn efficiently, creating carbon deposits.
Intermittent use: frequent start and stop cycles accelerate residue buildup.
Improper generator sizing: oversized equipment compared to actual demand.
Consequences of Wet Stacking
Increased pollutant emissions.
Clogging of the exhaust system and turbocharger.
Reduced generator efficiency.
Higher fuel consumption.
Shortened lifespan of engine components.
Increased corrective maintenance costs.
How to Prevent Wet Stacking
Run the generator regularly at loads above 60%.
Perform periodic load bank tests to burn off accumulated residues.
Implement preventive maintenance programs.
Properly size generators according to real energy requirements.
Use pre-heating systems to improve combustion in cold environments.
Conclusion
Wet stacking is a common issue in diesel generators that operate continuously under low loads. However, it can be avoided through proper sizing, good operating practices, and preventive maintenance, ensuring efficiency, reliability, and extended service life of the equipment.
