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With the promotion of renewable energy, natural gas's advantage is being cut as its prices fluctuate largely. This study proposes a robust mathematical model to simulate the changes in electricity structure and hydrogen supply with the fluctuation of natural gas prices. The simulation model is applied to explore the impact of soaring natural gas prices on the electricity market in China. The results demonstrate that high natural gas prices are more likely to promote the development of low-cost nonrenewable power generation rather than renewable power generation under a policy of low-carbon tax. Coal power still dominates the electricity market with a share of 42% and accounts for 66% in hydrogen production due to its low price and mature craftsmanship. Natural gas is the indispensable transitional energy for the transformation of the power structure despite its high prices, occupying 17% in the electricity market and 15% in hydrogen production. In conclusion, fossil energy will gradually change from direct combustion and utilization to the production of renewable energy such as hydrogen energy. Finally, policy recommendations for the structure of the electricity market and the supply of hydrogen energy are proposed. • A R-MILP model has been developed to simulate the changes in electricity market. • Energy prices uncertainty is considered for reflecting energy competitiveness. • A universal approach for analyzing the evolution of energy structure is proposed. • Explore energy structure changes brought by high gas prices in China. [ABSTRACT FROM AUTHOR]

Electrolysis hydrogen generation technology is one of the feasible ways to alleviate the problem of wind electricity curtailment. One promising hydrogen value-added application is to blend hydrogen into the natural gas grid and sell it as the heat energy carrier. This paper aims to discuss the feasibility of a roadmap to urban energy internet with wind electricity-natural gas nexus. Firstly, a framework is raised to integrate wind electricity generation, electrolysis hydrogen generation, and hydrogen-natural gas blending systems. Secondly, a series of reasonable hydrogen supply profiles are provided based on annual electricity curtailment and realistic natural gas scheduling. Then, an energy optimisation model and a techno-economic model are applied to simulate the generation of electricity and hydrogen, as well as determine the most economical hydrogen supply scheme. Finally, a case study in the Beijing-Tianjin-Hebei region of China is taken to validate the benefits of the proposed roadmap. The preferred scheme is worked out with the net present value of 88.8 M$, including the economy configurations of the electricity-hydrogen hybrid generation system, as well as the hydrogen-natural gas blending plan. The results also indicate that annual electricity curtailment and annual carbon emission are decreased by 204 GWh (48.8%) and 40.2 kt (49.9%). • Raise a roadmap to urban energy internet with wind electricity-natural gas nexus. • Set a framework to integrate electrolysis hydrogen generation and blending systems. • Propose an overall optimisation model for economic and environmental analysis. • Hydrogen supply depends on wind electricity curtailment and natural gas scheduling. • The improved economic and environmental benefits in a real case are identified. [ABSTRACT FROM AUTHOR]

In coal-dominated regions, hydrogen by-product from refineries can be used to replace coal as heating fuel. This can be a viable method for reducing CO 2 emissions. Given that hydrogen injection into existing natural gas pipeline networks is an economical way to utilise this clean gas, this paper explores its benefits by studying its supply chain optimisation and analysing its reliability. First, a mixed-integer linear programming model is developed to minimise transport and dissatisfaction costs. Material balance, supply and transport of natural gas, operation of pipeline networks, and hydrogen injection are considered as constraints. The operating plans of a regional natural gas supply chain (NGSC), with and without hydrogen injection, are optimised. Then, three types of indicators – economic indices, coal and hydrogen as percentages of total energy consumption, and CO 2 emissions – are applied to compare the performance of the NGSC in different situations. A case verifies the proposed model and shows the influence of utilising hydrogen in an NGSC. The optimal operating plans under one standard and two non-standard conditions are calculated, and the reliability of the supply chain is analysed. Results illustrate that injecting hydrogen in the NGSC is beneficial in reducing CO 2 emissions and operating costs. • Implementing hydrogen by-product to replace the coal reduces CO 2 emissions. • A Framework is proposed to evaluate the economic and environmental benefits. • An MILP model is developed to minimise transport and dissatisfaction costs. • A case is studied to show the influence of utilising hydrogen on an NGSC. • The performance of the NGSC in several conditions are analysed. [ABSTRACT FROM AUTHOR]