Hydrogen is the most abundant element in the universe, though it is not found naturally on Earth. Hydrogen must be extracted from other sources. In its purest form, hydrogen is a non-toxic colorless and odorless gas.
Hydrogen (when used as a fuel), like electricity, is an energy carrier rather than an energy resource. Both electricity and hydrogen can be produced from all energy resources available (including, natural gas, solar and wind electrolysis, biomass, and others). Hydrogen and electricity can be generated from greenhouse gas-neutral sources, addressing climate change and urban air quality problems. As with electricity, hydrogen can also be produced from sustainable domestic and renewable energy resources, such as wind or solar-powered electrolysis, which enhances our long term energy security.