Japanese auto giant Toyota Motor’s fuel cell vehicle Mirai leaves a hydrogen station of Japan’s gas distributor Iwatani in Tokyo.

Japan has lofty ambitions to become a “hydrogen society” where homes and fuel-cell cars are powered by the emissions-free energy source, but observers say price and convenience are keeping the plan from taking off.

Prime Minister Shinzo Abe has dubbed hydrogen the “energy of the future”, and hopes it will help Tokyo meet the modest emissions targets it has set ahead of a UN climate change conference this month.

Tokyo wants to see cars, buses, and buildings powered by the clean energy in the coming years, and has even laid out plans for a “hydrogen highway” peppered with fuelling stations, all in time for the Tokyo 2020 Olympics.

Japan, which is the world’s sixth largest greenhouse gas emitter, has “constructed a vision of society” based on hydrogen, said Pierre-Etienne Franc, director of advanced technologies for French industrial gas firm Air Liquide.

Toyota’s hydrogen car, Mirai — which means “future” in Japanese — launched in 2014, after two decades of tireless research. The car recently rolled out in the United States and Europe. While it has wowed some, production has lagged behind demand and high costs have turned off many consumers.

A Mirai fuel-cell vehicle costs 6.7 million yen, or about $55,000, nearly double a comparable electric car. Fuel cells work by combining hydrogen and oxygen in an electrochemical reaction, which produces electricity. This can then be used to power vehicles or home generators.

Environmentally-conscious motorists like the Mirai because unlike conventional cars, it does not emit CO2. It also has a longer cruising range and takes only a few minutes to refuel, compared to several hours required for an electric rival.

“(Fuel-cell vehicles) appear to be the ideal green cars,” said Hisashi Nakai, who works in Toyota’s strategy planning department.

Nakai dismisses concerns that hydrogen poses a dangerous explosion risk — the gas is highly volatile and flammable — insisting the tank of the car has been rigourously tested and can “withstand any shocks”. But he admits price remains a major barrier.

“The main problem is the cost — we have just started, it doesn’t happen overnight,” he adds. Air Liquide’s Franc also bemoaned heavy regulations on building fuelling stations.

“In its superb ambition, Japan has failed in its strategy with extremely restrictive regulations,” he said, referring to safety rules to prevent leakage of the flammable gas.