A method for controlling fuel flow in a multi-fuel engine is disclosed. The method includes determining an estimated lower heating value (LHV) of a gaseous fuel by, at least, comparing a mapped volume flow value with an input volume flow value, the input volume flow value based on the input power. The method further includes determining a gaseous fuel flow rate for the gaseous fuel, the gaseous fuel flow rate based on, at least, a specific fuel substitution ratio of the gaseous fuel and a secondary fuel and the estimate LHV of the gaseous fuel source.