Abstract
Fossil fuels, renewable, nuclear, or fissile fuels are the main energy sources. Fossil fuels, especially oil, are still the most popular source of energy in the world. Importance of clean and renewable energy sources (RESs) has increased significantly in recent years. The authors analyze current and future energy situation in the world. The futuristic concept of engine fuel has become the promising fuel resource which can compete with oil. The paper analyzes and discusses also the alternative energy sources in the future.