Abstract: The invention relates to a method of liquefying a gas, in particular a natural gas by cooling it under pressure in stages. The gas is cooled by means of at least two refrigerants, one refrigerant circulating in a closed refrigeration circuit and another refrigerant circulating in another closed refrigeration circuit, wherein the compositions of the two refrigerants differ from each other. According to the invention a compressor in a closed refrigeration circuit is driven by a gas turbine and the refrigerant circulating in the last mentioned closed refrigeration circuit is cooled by ambient air after compression. Furthermore, according to the invention, in addition to the compressor an electric generator is driven by the gas turbine in such a manner that, when extra gas turbine power is available because of a variation of the ambient air temperature, electric power is generated so that the gas turbine will operate at, or at about, its design load.