Current initiatives to combat climate change and achieve energy independence encourage the development and application of bioenergy and other renewable energy sources. Biofuels in any state of matter have been the focus of a lot of research, development and use in recent years. Bioenergy has been employed in cooking, illumination and thermal insulation since the dawn of human existence. Three to four times as much energy is stored in the yearly biomass produced by terrestrial plants as is currently required by the world. Solid biofuels include things like charcoal, pellets, wood chips, and firewood. While the application of wood pellets and wood chips in making electricity and heating homes (biopower) has doubled in the previous ten years and is expected to keep going up a lot. The amount of firewood and charcoal used around the world has kept basically the same. Not only is 15–20 billion gallons of biodiesel or bioethanol produced each year, mostly from food crops, but industrial bioethanol synthesis from lignocellulosic materials has just recently begun. Oilseed-based biodiesel production now totals 5670 million gallons annually; further expansion will rely on the creation of fresh raw material. Drop-in biofuels and bio-oil are still in their inception and have challenges with economical conversion and improvement. Hence, the present book chapter deals with renewable energy a substitute to conventional fossil fuel for sustainable life and energy security.