Renewable energy systems are integrated networks of technologies designed to capture, convert, store, and distribute energy from naturally replenishing sources such as solar, wind, hydro, geothermal, and biomass. Functioning as a sustainable alternative to fossil fuels, these systems aim to generate electricity and heat with minimal environmental impact and reduced greenhouse gas emissions. The field involves not just the primary generation components like wind turbines or photovoltaic panels, but the entire infrastructure, including inverters, battery storage, and grid management, making it a crucial area of applied science focused on engineering a clean and resilient power infrastructure.