Hydrogen is being used in automobiles across the world. In the Scottish city of Aberdeen 10 hydrogen fuel cell buses are in operation. The buses take residents around the city in an initiative to lower emissions and improve air quality.

Green hydrogen is becoming a popular choice because of its environmental friendly use. In essence, “it’s hydrogen stemming from green sources,” Jorgo Chatzimarkakis, secretary general of Hydrogen Europe, told CNBC: Sustainable Energy. “So if you produce energy from wind or solar, turn it into electricity and then turn it into hydrogen, this is green hydrogen,” he added.

According to the U.S. Department of Energy, hydrogen can “store and deliver usable energy.” Hydrogen does not “exist by itself in nature.”   

When the chemical energy in hydrogen is transformed into electricity by fuel cells and combined with an electric motor is more powerful than internal combustion engine, which operates using gasoline.

Bruce Logan, from Pennsylvania State University, told Sustainable Energy, “Right now, most hydrogen is made from fossil fuels.” Using various methods, sources like fossil fuel, solar and geothermal have the potential to produce hydrogen. The methods include biological processes, thermochemical processes and electrolytic processes, explains the DOE.

“What we’re doing is taking primarily natural gas, making that hydrogen and then using that hydrogen. So we have benefits from using the hydrogen but it still relies upon fossil fuels,” Logan said.

Even the European Commission has described hydrogen as an energy carrier: “great potential for clean, efficient power in stationary, portable and transport applications.”