Review of Advanced Optimal Power Flow Techniques for Multi-Energy Systems with High Renewable Penetration

The global transition towards Integrated Energy Systems (IES) that integrate high penetrations of Renewable Energy Sources (RES) is pivotal in addressing critical challenges related to climate change, energy efficiency, and long-term sustainability. However, the integration of RES introduces operational complexities due to their inherent variability and unpredictability. Optimal Power Flow (OPF) techniques, which are integral to the efficient management and operation of IES, must adapt to these challenges. This review critically examines the state-of-the-art OPF strategies in renewable-integrated IES, addressing key challenges such as uncertainty in renewable energy generation, computational complexity, and the need for multi-energy coordination. We also analyze emerging solutions such as machine learning, quantum computing, digital twins, and blockchain technologies, which are expected to play a transformative role in the optimization of multi-energy systems. Through detailed case studies, this review explores practical applications, identifying both advancements and ongoing gaps, and proposes future research avenues to enhance OPF performance in the face of evolving energy landscapes.