Sustainable sources refer to energy sources that are renewable, efficient, and do not deplete the Earth's natural resources. These sources of energy include solar, wind, hydro, geothermal, and biomass energy. Sustainable sources of energy are important for reducing greenhouse gas emissions, combating climate change, and promoting environmental conservation. Research in this area focuses on developing new technologies, improving existing infrastructure, and finding innovative solutions to make sustainable energy sources more accessible and affordable for the global population.