Effectiveness of the Hydrogen Production, Storage and Utilization Chain

The paper evaluates the effectiveness of a power-to-gas hydrogen chain, comprising the production, storage and utilization sections. The production section is based on alkaline electrolyzers producing about 18.6 kg hydrogen per MWh supplied electric energy derived from renewable (wind) sources. Next, hydrogen is transported to an underground storage facility (UGF), assuming that the pressure of the produced hydrogen is sufficient to provide its transportation to the storage site. Energy demand required for hydrogen compression to the UGF is accounted for, and the maximum level of hydrogen losses is evaluated. Finally, three options for hydrogen utilization are considered: (1) hydrogen is co-fired in a gas turbine, (2) it is supplied to hydrogen vehicles, (3) it is used for process purposes replacing the existing production based on steam methane reforming. Moreover, energy effects related to the replaced oxygen production are optionally taken into account. It has been shown that the choice of a scenario (co-firing//vehicles/process application) and, to a lesser degree, the possibility of using the generated oxygen strongly affects the overall process performance which may vary between low values of 20% (energy generation), 70–80% for process application (replacement of steam methane reforming) and more than 90% for vehicle application (replacement of diesel fuel). In conclusion, the process may provide excellent energy performance for dedicated hydrogen users, and a less favorable yet still considerable option for energy storage for renewable sources.