Most energy alternatives, whether directly or indirectly, depend on the sun as their primary energy source. Solar energy is harnessed directly through photovoltaic cells and solar thermal systems. Indirectly, the sun drives wind patterns, which are captured by wind turbines, and it fuels the water cycle, enabling hydroelectric power. Additionally, biomass energy relies on plants that grow through photosynthesis, a process powered by sunlight.
Even fossil fuels, which are not considered renewable, are essentially stored solar energy. They were formed from ancient plants and organisms that relied on the sun for growth. Over millions of years, these organic materials were transformed into coal, oil, and natural gas.
In summary, the sun is the foundational energy source that supports most of the energy alternatives we use today.