The massive increase in energy consumption, especially over the past several years, has raised fears that the world’s fuel and other resource reserves would be drained in the coming years. Over the years, low-cost, long-term energy has been viewed as the foundation of any country’s social and economic success. Nonetheless, in recent decades, a bigger section of the population of developing economies has had limited access to inexpensive and sustainable energy, contributing greatly to these countries’ poor economic and social growth. This study was therefore a review of the various sources of energy and their applications.