Evaluation of the introduction of a hydrogen supply chain using a conventional gas pipeline–A case study of the Qinghai–Shanghai hydrogen supply chain

A large-scale hydrogen supply chain is an alternative for the transportation of energy generated from a renewable energy source. Utilizing this technology would drastically improve the generation of clean energy. Therefore, an analysis method to estimate the economic and environmental benefits of the introduction of a hydrogen supply chain using an existing pipeline is developed. The proposed method first estimates the energy and exergy flows in the system to calculate the overall efficiency of these quantities. Afterward, the payback period is estimated based on the overall energy efficiency using the discounted cash flow (DCF) method. The overall efficiency of the system, based on the energy analysis presented, would seem to be the final delivered electrical, fuel and useable heat energy delivered to end use divided by the input solar and wind energy. Furthermore, the environmental effects due to the introduction of the systems are evaluated considering the reduction of global warming and air pollution gases, such as CO2 and PM2.5. The proposed analysis method was applied considering a natural gas pipeline that connects Qinghai and Shanghai. As a result, conversion ratios of 24.9% for electricity and 17.5% for heat were achieved, with the overall efficiency of the system of 42.4% based on the electricity obtained from photovoltaics. 3.02 Gt of CO2, 104 kt of SOx, and 134 kt of NOx, which represent 3.3%, 0.5%, and 0.6% of the annual discharge in China, respectively, and 8.66 kt of PM2.5 would be reduced every year. Furthermore, a reduction of 953 Mt in coal consumption is expected. The payback period of the proposed system using the DCF method is 4.17 and 2.28 years for the two alternatives evaluated in this work. The cash flow of the DCF is influenced by installation cost and operation cost of equipment.