California is already home to the nation's sole hydrogen fueling infrastructure, and funds are in place to build more such stations over the next few years.
That's why the Golden State is now the sole U.S. market for the Hyundai Tucson Fuel Cell and the upcoming 2016 Toyota Mirai--the only fuel-cell cars on sale in the U.S. right now.
For hydrogen to have a significant impact, it must obviously expand beyond this single state, as large as California is.
The Northeast Electrochemical Energy Storage Cluster (NEESC) trade group has laid out a blueprint of how the cars could come to the eight states of its namesake region.
The group represents interests hoping to increase the use of fuel cells for energy storage. But it is apparently interested in transportation applications for hydrogen as well.
First 2015 Hyundai Tucson Fuel Cell delivered to lessee at Tustin Hyundai, June 2014
It recently proposed eight individual plans (via Green Car Congress), one per state, that call for 10,800 fuel-cell cars, 640 fuel-cell buses, and a network of 110 refueling stations to support them over the next 10 years.
That compares to California's plans for up to 100 hydrogen fueling stations to support 25,000 vehicles by 2020.
The plan for the Northeast covers Connecticut, Maine, Massachusetts, New Hampshire, New Jersey, New York, Rhode Island, and Vermont, each of which accounts for a different-sized share of the total.
New Jersey is expected to have the largest hydrogen fleet, with 5,455 passenger cars (including 130 for government fleets) and 173 buses, supported by 55 to 60 fueling stations.
In contrast, Vermont is expected to have just 82 fuel-cell vehicles on its roads a decade from now: 72 private cars, 8 government cars, and 2 buses--and just one or two fueling stations.
The plan also tracks electricity-generation capacity from fuel cells, and in this case New York will take the lead with 543 to 724 megawatts.
Audi A7 h-tron quattro
Those are ambitious goals, but they are likely to be no more than a drop in the bucket compared to the numbers of plug-in electric cars on the roads in the same timeframe.
At the current rate of adoption, Northeast roads could have 1 million or more battery-electric cars and plug-in hybrids within the decade.
Connecticut, Massachusetts, New York, Rhode Island, and Vermont are already part of a separate eight-state coalition that hopes to put a total of 3.3 million zero-emission vehicles on the road by 2025.
The other states are California, Maryland, and Oregon, with the two West Coast states together likely to have the lion's share of the total.
Those vehicles would include both battery-electric and hydrogen fuel-cell cars.