Renewable energy refers to energy sources that are naturally replenished on a human timescale and are considered sustainable alternatives to fossil fuels. These sources include:

1. Solar Energy – Captured from the sun using photovoltaic (PV) panels or solar thermal systems.

2. Wind Energy – Generated by wind turbines that convert kinetic energy into electricity.

3. Hydropower – Utilizes flowing water (rivers, dams, or tides) to generate electricity.

4. Geothermal Energy – Extracted from heat within the Earth's crust to produce electricity or heating.

5. Biomass Energy – Derived from organic materials (plants, wood, waste) and converted into fuel or electricity.