The design of a PV-hydrogen gas turbine hybrid power plant is proposed to generate 100 MW electrical load. This electrical power is supplied directly from PV solar panels, and in the case of shortage or lack of solar radiation, it is supplied by a gas turbine power plant working on hydrogen fuel which is produced through using electrolysis of water by a PV generator. The hydrogen produced is stored directly in gas tanks under appropriate pressure. In the case of inability in supplying the load from PV generator, hydrogen fuel will be used through gas turbine. This study is examined in two cases; case (a): the design of the PV power plant based on worst case scenario; which corresponds to the minimum solar radiation and minimum sunshine hours during the year), and case (b): the design of the PV power plant based on average case scenario; which corresponds to the average solar radiation and average sunshine hours during the year. In both cases, the size of the gas turbine power plant and the size of the photovoltaic arrays required for operating day load, the number of water electrolysers, the capacity of hydrogen tanks required for storage purposes; all were calculated. The economic cost in each individual case was analysed taking into account, a profit of 25% of the initial cost. It was found that the price of the electricity produced is 0.12 $/kWh for worst case scenario, and 0.16 $/kWh for the average scenario. The payback period is 13 years and 15 years for the worst and the average scenarios respectively based on 8% interest rate. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.