Abstract. This review paper provides a comprehensive analysis of future low-inertia power systems, focusing on the challenges posed by increased renewable energy penetration. The impact of low inertia on frequency response and system stability is examined, along with the critical penetration limit for renewable energy sources. The paper reviews various virtual inertia emulation techniques, including virtual synchronous machines, virtual induction machines, and inertia emulation in wind turbines and solar PV panels. Additionally, it explores specific methods such as VISMA, virtual synchronous generator, synchronverter, power synchronization control, and cascade virtual synchronous machine. The review also covers inertia algorithms in wind turbines, encompassing droop control, hidden inertia emulation, fast power reserve, over speed control, and pitch angle control. Furthermore, the paper discusses inertia estimation techniques, including both model-based and measurement-based approaches. The insights provided in this review will assist researchers and practitioners in developing effective solutions for addressing low inertia challenges in future power systems with high renewable energy integration.