Green hydrogen the "Swiss Army knife" David Yellen, program assistant for the Global Energy Center at the Atlantic Council, called green hydrogen the "Swiss Army knife" of the transition to clean energy.
The last decade has seen "amazing cost reductions" in solar and wind power and especially in batteries, Nemet said.
But those energy sources won't do well for heavy manufacturing, long-distance transport such as trucking, cargo ships and aircraft, so green hydrogen, with its high-energy density, is expected to fill the gaps.
For example, the weight of a battery is an issue for air travel. Jet fuel burns as it goes, but batteries stay the same weight throughout the trip, Nemet said.
Also, the space batteries take up make them problematic for trucks, Friedmann said, while hydrogen can be used in steel mills due to its ability to produce high-quality heat and in the form of ammonia on ships (which serves as fuel).
Hydrogen also beats batteries for long-term storage, Bell said.
"For this big investment for hydrogen to pay off, it's always going to have to compete with batteries," he added.
Solutions need to be found for safely storying hydrogen on aircraft and building infrastructure for the alternative fuel at airports, said European airplane manufacturer Airbus in a statement in October. Despite those challenges, the company still believes green hydrogen will play a significant role in decreasing emissions from air travel.
Green hydrogen can use existing infrastructure
One of the reasons why there is so much interest and enthusiasm surrounding green hydrogen is that the infrastructure already exists for it, Friedmann said.
Because of the way green hydrogen is produced, it likely won't be used where it is made, Nemet said. Therefore, it will need to be pressurized and then moved, either through a pipeline, ship or truck using the existing infrastructure in place.
With hydrogen, at about a 10% ratio, it's possible "to just throw into natural gas pipelines today, and it does OK," Friedmann said.
The refineries that exist that use gray hydrogen to make chemicals can also do so using green hydrogen, Nemet said, and it also is compatible with existing industrial machinery in a lot of cases, Yellen said.
In addition, a lot of the engines on long-haul trucks can run on hydrogen, but eventually they will need to be replaced with hydrogen fuel cells, which are expensive, Friedmann said.
Another benefit of green hydrogen is it can be blended into natural gas, Friedmann said.