Optimal power reallocation of large-scale grid-connected photovoltaic power station integrated with hydrogen production

With the consumption of fossil fuels and the aggravation of environmental pollution, the use of photovoltaic (PV) power to produce hydrogen is of great significance to improve power utilization and promote cleaner production. Determining the optimal power and capacity allocation is an urgent problem in the planning and construction stages of hybrid systems. This study focused on exploring a universal method for determining the power reallocation and capacity configuration for a grid-connected PV power station integrated hydrogen production system. First, considering the PV output characteristics and electricity transmission requirements, a model for determining the grid connection dispatch with the objective of minimizing PV curtailment was constructed. The operational control strategies of the hydrogen system considering the hydrogen production process under different storage configurations were proposed. Then, an optimal capacity decision method considering grid connection modes, hydrogen storage, and transportation modes, and hydrogen transportation distance was formed. Finally, a case study on the 100 MW PV demonstration base in the Qinghai province of China was used to confirm their feasibility. The results indicated that: (1) the liquid hydrogen is more suitable for long-distance transportation, and the 5-segment mode is best for grid connection; (2) the optimal capacity configurations for the hydrogen production system under the 5-segment grid connection mode were three sets of 800 Nm³/hr electrolyzers and 3 MW of the liquefier; and (3) when the transportation distance is 3000 km, the net present value (NPV) of the entire life cycle is $15.85 million, which is about four times that of the PV demonstration base only for grid connection ($3.83 million), and the annual hydrogen output is 7.01 million Nm³, which can reduce CO₂ emissions by 7.72 thousand tons. Thus, the method has important guiding significance for reducing carbon dioxide emissions and realizing cleaner production.