The increasing integration of electricity, gas, and hydrogen systems, spurred by blending green hydrogen into existing natural gas pipelines, is paving the way for a future dominated by renewable energy. However, the integration poses significant challenges for efficient, safe operation across varying hydrogen penetration levels. This paper conducts a systematic review of the literature on hydrogen-blended integrated gas-electricity systems with a focus on modeling, optimization, and control technologies. First, key technologies and international demonstration projects are introduced to provide a comprehensive overview of the current state and development trends in HIGES. Then, numerical modeling and solution methods are summarized, along with their application scenarios, thereby serving as a theoretical foundation for quantitative research. Next, optimization under normal operating conditions for the multi-entity integrated system is reviewed, with explorations into enhancing economic and effective operation through scheduling, planning, and market mechanisms. Research advances in security analysis and control technologies for fault-state scenarios are reviewed to address the complex operating characteristics. Finally, four pivotal research directions are highlighted.

Fossil fuel depletion and environmental pollution problems promote development of renewable energy (RE) globally. With increasing penetration of RE, operation security and economy of power systems (PS) are greatly impacted by fluctuation and intermittence of renewable power. In this paper, information gap decision theory (IGDT) is adapted to handle uncertainty of wind power generation. Based on conventional IGDT method, linear regulation strategy (LRS) and robust linear optimization (RLO) method are integrated to reformulate the model for rigorously considering security constraints. Then a robustness assessment method based on hybrid RLO-IGDT approach is proposed for analyzing robustness and economic performance of PS. Moreover, a risk-averse linearization method is adapted to convert the proposed assessment model into a mixed integer linear programming (MILP) problem for convenient optimization without robustness loss. Finally, results of case studies validate superiority of proposed method in guaranteeing operation security rigorously and effectiveness in assessment of RSR for PS without overestimation.

Power-to-hydrogen by electrolysis (PtHE) is a promising technology in the carbon-neutral evolution of energy. PtHE not only contributes to renewable energy integration but also accelerates decarbonization in industrial sectors through green hydrogen production. This paper presents a comprehensive review of PtHE technology. First, technical solutions in PtHE technology are introduced to clarify pros and cons of one another. Besides, the multiphysics coupling and the multi-energy flow are investigated to reveal the insight mechanism during operation of compactly assembled industrial PtHE plants. Then, the development trends of core components in PtHE plants, including electrocatalysts, electrode plates and operation strategy, are reviewed, respectively. Research thrusts needed for PtHE in carbon-neutral transition are also summarized. Finally, three configurations of the PtHE plant in energy system integration are introduced, which can achieve renewable energy integration and efficient energy utilization.