The invention relates to an ethylene plant, comprising a cracking furnace for converting a hydrocarbon feedstock into a cracked gas stream; a separation section to provide at least an ethylene-enriched product stream, a hydrogen-enriched fuel stream and a methane-enriched fuel stream from the cracked gas stream; a passage way for feeding at least part of the hydrogen-enriched fuel from the separation section to a burner of the cracking furnace and/or a passage way for feeding at least part of the hydrogen-enriched fuel from the separation section to a burner of a waste heat recovery boiler of a combined cycle gas turbine power plant(CCGT); a methane storage configured for storing methane-enriched fuel and a passage way for feeding at least part of the methane-enriched fuel from the separation section to the storage; the CCGT, comprising a gas turbine—comprising a combustor—and a passage way for feeding at least part of the methane-enriched fuel from the storage to the combustor of the gas turbine of the CCGT, which CCGT is configured to generate electric power and/or to generate high pressure steam to drive a steam turbine forming part of a steam generation circuit of the ethylene plant; and an electric power connection for providing part of the power for operating the plant, which is a connection to an electric power system to produce electric power from a renewable source.