In this paper, the hybrid concept to use renewable electricity to produce hydrogen with an electrolyser in combination with a battery is introduced and analysed. This hybrid system opens the possibility to optimise operation and to increase operation times of the system and thus to improve the techno-economic performance. To analyse the performance, a model has been developed, which designs and operates a single or hybrid power-to-gas system in a cost optimal manner. The underlying method is a mixed integer linear programming (MILP) approach, which minimises total system costs. The cost optimisation modelling is performed by a case study for a hybrid electrolyser/battery system directly coupled with a large PV power plant without grid connection. The results show, that batteries can support electrolyser operation in a reasonable way. This is however associated with higher hydrogen production costs and not competitive compared to the installation of additional electrolyser capacity or curtailment of electricity.