Since humans were created, they have always depended on an external energy source. Before the discovery of the use of fossil fuels, people used the sun as their primary source of external energy. The sun provides heat, light, and photosynthesis for food that humans and animals need to produce their work energy. And it also affects the movement of wind and water which humans also use to produce energy for heavy labor. The discovery of the use of fossil fuels allowed the start of the industrial revolution at the beginning of the 19th century. And this also led to the growth of human population, technology and wealth. Since then, humans have used fossil fuels as their primary source of external energy. This period could well be renamed the energy revolution. But if we continuously use fossil fuels as energy, it will pose a big problem for humanity in the future. Indeed, the continued use of fossil fuels threatens our global energy supply and also has many negative effects on our environment. Global energy demand is expected to double by 2050 in response to population growth and industrialization in developing countries. The supply of fossil fuels is limited by its limited quantity on Earth and it will soon be exhausted if we use it continually. The longevity of the fossil fuel supply is reduced by the energy consumed through its conversion to a form of energy suitable for human use. While the world's oil and gas reserves are concentrated in a few regions of the world, demand is increasing everywhere. As a result, the world's energy supply in the future is difficult to ensure. Furthermore, the use of fossil fuels is not good and endangers human health. This is because...... middle of document ......More research, effort, time and money are needed to actualize the use of hydrogen as a future source of global energy.Works CitedBraun, Harry W. The Phoenix Project: moving from oil to hydrogen. Phoenix: SPI Publications & Productions, 2000. Crabtree, George W., Mildred S. Dresselhaus, and Michelle V. Buchanan. “The hydrogen economy”. December 2004. October 12, 2005. Gorman, Jessica. “Hydrogen: the next generation.” October 12, 2002. October 12, 2005, “Hydrogen Topics.” October 4, 2005. US Department of Energy. October 12, 2005. Weisz, Paul B. “Fundamental Choices and Constraints on Long-Term Energy Supply.” July 2004. October 12 2005 .