Japan built the world’s third-largest economy on an industrial base powered by imported oil, gas and coal.

Now, it is planning to shift a big chunk of that power to hydrogen, in one of the world’s biggest bets on an energy source long dismissed as too costly and inefficient to be realistic.

The change is a vital piece of the country’s plan to eliminate carbon emissions in 30 years. If it succeeds, it could also lay the groundwork for a global supply chain that would finally let hydrogen come into its own as an energy source and further sideline oil and coal—similar to the way the country pioneered liquefied natural gas in the 1970s, some experts say.