This document discusses various non-conventional and renewable energy sources as alternatives to conventional sources that are being overexploited. It describes solar energy technologies like solar water heaters and solar cells. It also discusses wind energy from turbines, tidal energy from barrages, hydroelectric energy from dams, biomass energy from waste products, geothermal energy from heat within the Earth, and the potential to generate wind power from passing trains. These alternative energy sources provide more sustainable options to meet future energy needs.