The article presents a comparative analysis of effectiveness of the approaches developed by the authors to ensuring a further development of nuclear energy industry as a pollution-free energy source. To solve this problem, several options for using environmentally friendly hydrogen fuel were considered to ensure a high installed power factor of NPPs and/or maneuverability of existing and planned double-loop NPPs with a water coolant. It is proposed to accumulate off-peak electricity by means of water electrolysis to obtain hydrogen and oxygen, which ensures the basic operation mode of NPP and provides a possibility to use hydrogen/oxygen to produce peak electricity. The given approach is compared with the basic scheme of marketable hydrogen and oxygen production including their additional purification. The economic feasibility is estimated with account for the effect from replacement of environmentally harmful plants based on gas turbine units, including the effect of preventing forced unloading of NPPs and various options to the target prices for nuclear and hydrocarbon fuel. As a result, the main technical and economic indicators of the proposed approaches were determined, including the cost and accumulated net present value. Based on the assessments made, it is shown that the options for providing NPPs with a basic electrical load based on the proposed approaches are efficient and competitive. Production of hydrogen and oxygen with a subsequent production of peak electricity, i.e. the use of a hydrogen power complex as an off-peak energy storage allows achieving the maximum economic effect. The provided estimates show the relevance and prospects for solving the problem of providing NPPs with a baseline electrical load under conditions of increasing their share in the energy grid based on the combination with a hydrogen power complex.