How is the fuel consumption of a ship calculated?

The fuel consumption of a marine diesel engine is 190-230g/kWh, and is usually estimated at 210g/kWh. Under the rated navigation condition of the ship, the two main engines operate normally, and one generator runs one as a backup, so when calculating fuel consumption, it is two main engines and one generator. The fuel consumption of the main engine is the power of the main engine multiplied by the quantity and then multiplied by the unit fuel consumption.