A power system for powering a load is provided. The power system includes a plurality of power sources with each power source including an engine. A SCR system is associated with the engine of at least one of the plurality of power sources. A controller is in communication with the plurality of power sources. The controller is configured to receive engine operation information, emission output information associated with each engine and conversion efficiency information associated with the SCR system and selectively apportion the power demand presented by the load between each of the plurality of power sources based on minimizing total engine emissions across the plurality of power sources and using the engine operation information, the emission output information and the conversion efficiency information.

A power system for powering a load is provided. The power system includes a plurality of power sources with each power source including an engine. A SCR system is associated with the engine of at least one of the plurality of power sources. A controller is in communication with the plurality of power sources. The controller is configured to receive engine operation information, emission output information associated with each engine and conversion efficiency information associated with the SCR system and selectively apportion the power demand presented by the load between each of the plurality of power sources based on minimizing total engine emissions across the plurality of power sources and using the engine operation information, the emission output information and the conversion efficiency information.

A power system for powering a load is provided. The power system includes a plurality of power sources with each power source including an engine. A SCR system is associated with the engine of at least one of the plurality of power sources. A controller is in communication with the plurality of power sources. The controller is configured to receive engine operation information, emission output information associated with each engine and conversion efficiency information associated with the SCR system and selectively apportion the power demand presented by the load between each of the plurality of power sources based on minimizing total engine emissions across the plurality of power sources and using the engine operation information, the emission output information and the conversion efficiency information.

A power system for powering a load is provided. The power system includes a plurality of power sources with each power source including an engine. A SCR system is associated with the engine of at least one of the plurality of power sources. A controller is in communication with the plurality of power sources. The controller is configured to receive engine operation information, emission output information associated with each engine and conversion efficiency information associated with the SCR system and selectively apportion the power demand presented by the load between each of the plurality of power sources based on minimizing total engine emissions across the plurality of power sources and using the engine operation information, the emission output information and the conversion efficiency information.

Disclosed is a method for operating an engine for a vessel including an engine which can use both natural gas and fuel oil as fuel. According to the method for operating an engine for a vessel, each engine is operated in one of modes including: a gas mode in which the engine is driven using natural gas as fuel; a fuel oil mode in which the engine is driven using fuel oil as fuel; and a fuel distribution mode in which the engine simultaneously uses natural gas and fuel oil as fuel.