Last autumn, in the run-up to the COP26 climate summit, Marco Alverà called for nothing short of “a revolution” in global energy policy, one that puts hydrogen power at the center of the giant task of decarbonizing our homes, businesses, and factories.

Since taking the reins as CEO of Snam, one of Europe’s biggest natural-gas pipeline operators, in 2016, Alverà has been repositioning the Italian energy giant as a leader in supplying emissions-free hydrogen power. During the COVID lockdown, he wrote a book, The Hydrogen Revolution, outlining his vision for making green hydrogen a key technology to help the world’s biggest economies achieve their net-zero goals. “It’s simple to make and simple to use. You are essentially bottling sunlight from renewable energy sources in the form of hydrogen, and using it to bring clean energy to every corner of the globe,” Alverà wrote of “green hydrogen,” the latest term for using electricity derived from renewable energy sources—solar, wind, etc.—to produce hydrogen power.

Alverà is hardly alone in his enthusiasm. Climate hawks, green-energy startups, and dozens of countries are buzzing about the potential for hydrogen, the most abundant chemical substance in the universe. Naturally, that’s caught the attention of Wall Street. As Goldman Sachs detailed last month in an investor presentation, “Clean hydrogen has emerged as a critical technology to reach net-zero carbon emissions. This is why more than 30 countries have released official hydrogen strategies and road maps to ramp up their hydrogen consumption and develop the required infrastructure.”

Enticing chemistry

When converted into a fuel and burned, hydrogen’s chief by-product is water. (You may recall the experiment from your high school chemistry class that produced hydrogen gas by rigging a nine-volt battery with paper clips after plunging the power source into a container of water.) Hydrogen gas is also highly versatile. It can be blended with fuels such as natural gas, converted into methane, or burned as a superpotent fuel on its own, making it a promising energy source for heavily polluting industries such as steel and cement production and, eventually, shipping, long-haul trucking, and aviation.

Added bonus: Hydrogen power can be generated just about anywhere on the planet—which has suddenly made it particularly enticing to policymakers as Russia’s invasion of Ukraine has plunged the industrialized world into the biggest energy crisis in 50 years. When European Union leaders met last week to hash out a plan to break the trading bloc’s dependence on Russian gas, the word “hydrogen” was all over the draft proposal. European Commission President Ursula von der Leyen called the switch to hydrogen one of the innovations needed “to reduce EU demand for Russian gas by two-thirds before the end of the year.” In a way, the Europeans are catching up to the United States. Last autumn, as part of the U.S. Infrastructure Investment and Jobs Act, the Joe Biden administration pledged $9.5 billion to boost development of hydrogen power.

The main drawback of green hydrogen: the cost. Goldman Sachs research analyst Zoe Clarke estimates it will take upwards of $5 trillion in investment by companies and countries to build out the infrastructure and technology needed to make the hydrogen economy a reality. In her research, she cites the hydrogen electrolyzer, the core tech that converts water into hydrogen gas, as one area in need of investment.

Still, Goldman and Alverà see huge demand for clean hydrogen power propelling this market. Alverà sat down with Fortune last week to give us the bull case on hydrogen power. The conversation has been edited and condensed for clarity.

Fortune: Take us through the big numbers that will help us understand the potential road map and size of the so-called hydrogen economy.

Marco Alverà: Large-scale adoption is going to happen in the next five years. This is what got me so excited—what got me hooked. So we will have, by 2027, a hydrogen price of around $25 per megawatt-hour, which is less than a quarter of the price of gasoline today. Just 10 years ago, it was $600 per megawatt-hour.

So, your projection shows hydrogen is already very competitive with fossil fuels, in terms of price. Still, how confident are you in that 2027 forecast?

Very. My book came out in November. And in the book, I thought we were going to get to [a cost for hydrogen power of] $35 per megawatt-hour in the next 10 years. I’ve since spoken to more people who are making electrolyzers. [Electrolyzers use electricity to break water into hydrogen gas, a key technology for hydrogen power generation.] There are a lot of startups really putting capital behind this technology. And I now think we can get there by 2027—so instead of 2035 or 2030. My original time scale was driven off theory. Now that I’ve seen the data points of where these entrepreneurs are really pricing their product, [the 2027 forecast for widespread adoption] feels more accurate.

What can you tell us about the market interest?

[Just last week] European Union leaders met in Versailles. They issued a proposal to import 10 million tons of hydrogen by 2030 to help reduce the reliance on Russian gas. That’s a lot of hydrogen.

Would that be enough to completely replace Europe’s dependence on Russian natural gas?

It’s significant. EU leaders are saying Europe will need 20 million tons of hydrogen, of which 10 million will be imported, and 10 million will be produced within the EU. So, to simplify, hydrogen alone could make up almost half of what Russia supplies Europe today in natural gas.

Almost half sounds significant. Was anybody on the EU level even talking about such numbers a year ago?

Not even six months ago, no. I am probably one of the strongest advocates for hydrogen, and I wouldn’t have dreamt of such an ambitious policy.

More important, can Europe produce and import that much hydrogen fuel by 2030?

It’s possible, yes. The bottleneck is going to be the availability of solar panels and factories for the electrolyzers. So you’ll need a kind of concerted, almost wartime effort. If you ask Boeing to build a new plane, it would take them probably 12 years from concept. If you ask Snam to build a new pipeline, it would normally take us five years. But during the war, you had the U.S. Air Force making airplanes in six months. So we need to compress the permitting, the procurement, the building of factories. We do it for the climate. We do it for prices. We do it for energy security.

One of the big challenges is converting the hard-to-abate industry sectors—transportation, plus makers of fertilizers, ceramics, and cement—to hydrogen. How far off is that?

Not far. We’re going to have a hydrogen-powered train in Italy next year. We’re doing a trial, too, with ceramics manufacturers.

How much is Snam committing to the development of hydrogen power?

We have a €23 billion [about $25 billion] investment program over the next 10 years. We will be creating a hydrogen corridor from North Africa to Europe as part of that. We want to make sure that we understand the technology of all things related to hydrogen really well. That doesn’t mean we want to become a technology company. We remain an infrastructure company. But we really want to understand that technology well, which means we have a research team. We do venture capital. We look at startups. We work with universities.

You’ve already been experimenting with mixing hydrogen with natural gas, and running it through your pipelines to end users. Is that the business case?

Let me frame this a bit differently. A lot of people think I’m doing this because we want to keep the pipelines full, and want to extend the life of Snam. Not everyone knows my story. I joined Snam to pursue the vision of creating a global kind of Amazon of energy, an integrated platform with technology. So we launched a biomethane business, a hydrogen business, an energy efficiency business, a reforestation business, and a sustainable mobility business. We have these five startups we’ve incubated in Snam. We’ve defined our purpose as energy to inspire the world.