Finally, hydrogen gas can be extracted from various fuels and energy sources, such as natural gas, ethanol, water (via electrolysis using electricity) and, eventually, renewable energy systems.

• 最后一点，氢气可以由许多种燃料及能源中取得，例如天然气、乙醇、水（用电加以电解），甚至可再生的能源系统。