Abstract
Global warming, climate change, carbon emissions, energy security, and environmental degradation remain the defining challenges of the twenty-first century. Renewable energy innovation is the primary scientific and engineering response to these challenges. This chapter provides a comprehensive, current review of renewable energy technologies and innovations, drawing on 2024 statistics from the International Energy Agency (IEA), British Petroleum (BP), and the International Renewable Energy Agency (IRENA). Despite rapid growth, fossil fuels still supply approximately 87% of global energy, and carbon emissions reached a record 40.8 Gt CO2 in 2023. However, renewable electricity now represents 32% of global power generation, with solar capacity reaching 1,865 GW and wind capacity reaching 1,135 GW by end-2024. This chapter examines solar energy innovations (perovskite, tandem, bifacial, and building-integrated photovoltaics; agrivoltaics; floating solar; concentrated solar power), wind energy developments (offshore, floating, and AI-optimised turbines), bioenergy conversion technologies, hydropower and ocean energy systems, electrochemical and thermal energy storage, and the smart grid and digital infrastructure that enables renewable integration. Challenges, including intermittency, transmission constraints, rare earth supply chains, and storage costs, are analysed alongside future prospects for achieving net-zero electricity systems by 2050.