The energy which we are using in today's world for our needs is fossil fuel, we used to power our home by burning coal and run our vehicle through the oil or fossil fuel, but we should know that it is limited in quantity and cannot use it once it releases energy or burned, it is created by the dead organic materials like trees and animals etc. which slowly buried in the ground as the time goes and after 1000's of years it get pressurised and rise in temperature make that organic material into fossil fuel, so that's how the fossil fuel comes in existence, which we extract from the ground by drilling deep into the ground.
