This study examines the growing importance of cybersecurity in renewable energy systems and demonstrates how robust security measures are essential to keeping these systems stable, efficient, and safe. As renewable energy use increases worldwide, cyber risks targeting solar farms, wind turbines, smart grids, and energy storage units are also increasing, necessitating advanced protection strategies. Using a structured review of studies, technical reports, and industry publications from 2010 to 2024, this research identifies major cyber threats, common vulnerabilities, and the impact of current security practices. It examines modern solutions such as AI-based monitoring, anomaly detection tools, blockchain-supported energy transactions, secure communication protocols, and improved authentication systems. The study also highlights gaps in existing security frameworks and emphasizes the need for continuous upgrades, standardized guidelines, workforce training, and stronger coordination between energy companies, cybersecurity experts, and government entities. It recommends proactive policies, real-time threat intelligence sharing, and investment in advanced defensive technologies to build robust renewable energy infrastructure. The review concludes that the integration of new cybersecurity approaches is crucial to protecting future clean-energy networks and supporting the global transition to secure and sustainable power systems.