Renewable Hydrogen

Hydrogen is the simplest and most abundant element on earth—it consists of only one proton and one electron. Hydrogen can store and deliver usable energy, but it doesn't typically exist by itself in nature and must be produced from compounds that contain it. Hydrogen can be produced from diverse, domestic resources. Most hydrogen can also be produced through steam methane reforming, a high-temperature process in which steam reacts with a hydrocarbon fuel to produce hydrogen.

Another common hydrogen production method takes water, and separates the molecule H2O into oxygen and hydrogen through a process called electrolysis. Electrolysis takes place in an electrolyzer, which functions much like a fuel cell in reverse—instead of using the energy of a hydrogen molecule, like a fuel cell does, an electrolyzer produces hydrogen from water molecules.

Biological processes can also produce hydrogen through biological reactions using microbes such as bacteria and microalgae. In these processes, microbes consume plant material and produce hydrogen gas.

There are many ways to produce hydrogen using sunlight, including photobiological, photoelectrochemical, photovoltaic-driven electrolysis, and solar thermochemical processes.