Energiforsyningssystem og driftsfremgangsmåde

An energy supply system is provided with an electricity generating device for regeneratively generating electrical energy that can be fed into an electricity supply grid. The energy supply system includes an electricity generating device for regeneratively generating electrical energy which can be fed into an electricity supply grid, a hydrogen generating device for generating hydrogen using electrical energy from the regenerative electricity generating device, a methanation device for converting hydrogen generated by the hydrogen generating device and a supplied carbon oxide gas into a gas containing methane, and a gas providing device for providing a supplementary gas or a replacement gas in a variably specifiable supplementary/replacement gas quality suitable for feeding into a gas supply grid with the use of the gas containing methane from the methanation device and/or the hydrogen from the hydrogen generating device. A method of operating the system is also provided.