As gas compression operators contemplate sustainability goals alongside their operational metrics, determining the type of engine to use for a given project—rich-burn or lean-burn—involves important considerations. Below are some key areas to contemplate when making your decision.

Lambda is the ratio between the amount of oxygen in a combustion chamber and the amount that must be present for perfect combustion. There are two primary combustion architectures for industrial gas engines: stoichiometric or "rich burn" with lambda around 1.0, and "lean burn" with lambda greater than 1.5.

• Horsepower node.  If a project requires higher horsepower nodes, due to lower combustion temperatures lean-burn architecture allows for increased engine displacement before critical component temperatures reach design limits.
• Fuel efficiency. Generally, as combustion gas temperature increases, the heat of the gas changes, making it less efficient at turning thermal energy into mechanical force on the piston. The lower combustion temperature of a lean-burn engine result in greater fuel efficiency.
• Fuel tolerance. Though methane molecules are very stable, the potential for premature ignition (or knock) increases as the length of the hydrocarbon molecule increases. The lean-burn architecture allows for more aggressive rating strategies with higher British thermal unit (BTU) fuels.
• Engine longevity. Fewer compromises in performance are required for lean-burn engines, especially as the size of the engine scales up and heat rejection becomes more challenging. This contributes to a longer engine life.