Fuel system for a power plant

A fuel system for supplying gaseous fuel to a power plant, the fuel system comprising:

• a tank array comprising at least first and second tanks, each tank being configured to receive pressurised gaseous fuel for supply to the power plant;
• and
• an auxiliary control fluid delivery system, wherein the auxiliary control fluid delivery system comprises:
• a reservoir for auxiliary control fluid;
• an auxiliary control fluid pipeline configured to enable supply of the auxiliary control fluid to the tank array so as to cause discharge of the gaseous hydrogen fuel held in the tank array and to enable return of the auxiliary control fluid from the tank array;
• a valve arrangement which is operable to control the supply and return of auxiliary control fluid to and from the tank array, respectively, so as to control the discharge of the gaseous fuel to the power plant, the valve arrangement comprising a control valve arrangement operable to close the reservoir of auxiliary control fluid from the auxiliary control fluid pipeline to enable transfer of the auxiliary control fluid between the first and second tanks without re-entering the reservoir;
• and
• wherein each of the first and second tanks includes a separation element to separate the auxiliary control fluid from the gaseous fuel within the respective tank.