What is green hydrogen vs. blue hydrogen and why it matters

Hydrogen is the simplest element, and the most abundant substance in the universe.

When hydrogen burns, it generates energy in the form of heat, with water as a by-product. That means energy created from hydrogen generates no atmosphere-warming carbon dioxide, making it one of many potential energy sources that could help reduce carbon emissions and slow global warming.

But creating hydrogen and transforming it into a useful format requires energy — and that energy is not necessarily renewable. That process is also inefficient and expensive compared with other forms of energy, renewable or not. Many critics say the hydrogen industry a way for oil and gas giants to stall the adoption of pure renewable energy sources like solar and wind, giving them a “green” cover while still maintaining demand for their products.

Despite the debate, companies and the U.S. government alike are pushing forward the continued development of the hydrogen industry.

“In my travels around the world I can’t name a country that hasn’t expressed excitement about hydrogen,” John Kerry, special presidential envoy for climate, at the Department of Energy’s Hydrogen Shot Summit last August. “From Saudi Arabia to India to Germany to Japan we’re setting up hydrogen partnerships around the world to advance this critical technology that every country understands has the opportunity to play a vital role in the clean energy transition.”

Hydrogen may grow into a multitrillion-dollar global market, said Kerry, although he warned China wants to dominate it.

Producing hydrogen takes energy because hydrogen atoms don’t exist on their own — they are almost always stuck to another atom, often another element. (On earth, hydrogen is particularly abundant in the form of water, or H2O.) Creating pure hydrogen requires breaking those molecular bonds.

In the energy business, people refer to hydrogen by an array of colors to as shorthand for how it was created.

One may of making hydrogen is a process called electrolysis, when electricity is passed through a substance to force a chemical change — in this case, splitting H2O into hydrogen and oxygen.

Green hydrogen is when the energy used to power electrolysis comes from renewable sources like wind, water or solar.

Blue hydrogen is hydrogen produced from natural gas with a process of steam methane reforming, where natural gas is mixed with very hot steam and a catalyst. A chemical reaction occurs creating hydrogen and carbon monoxide. Water…