Wind and solar power are hard to store: the sun sets, and the wind dies down. The International Energy Agency has established that most grid batteries can hold only two to four hours of charge. That's not enough to cover several cloudy, windless days.

Joel Moser thinks the fix already exists, in a chemical most people know as fertilizer. The world makes roughly 200 million metric tons of ammonia a year, almost all of it from fossil fuels. Moser founded First Ammonia, which he leads as CEO, to produce ammonia a different way: from water, air and renewable power. He calls it a chemical battery, built to store and move electricity to places the grid can't reach. First Ammonia is now developing a flagship plant at the Port of Victoria, Texas.

Moser didn't start in energy. He spent decades as a project-finance lawyer, including work financing Citi Field, the New York Mets' stadium, before founding Aquamarine Investment Partners, an investment firm focused on real estate, energy and infrastructure. Aquamarine's early bets on low-carbon fuels gave him hands-on experience that led him to ammonia.

Moser also sits on the founding executive committee of the advisory board at Columbia's Center on Global Energy Policy, a leading voice on energy-transition policy. He's a peer reviewer on a NASA study exploring green ammonia as a fuel for commercial aviation.

In this interview, Moser explains what makes ammonia "green," why he calls it a chemical battery, and where demand is headed next. Edited excerpts:

What is green ammonia, and how does it differ from the gray and blue ammonia the industry already makes at scale?

Green ammonia is ammonia, NH3. It is nitrogen with hydrogen, and it's the same chemical substance regardless of how it's produced.

There's gray ammonia, which I also like to call conventional ammonia, which is how most ammonia in the world is made today. It's made by taking methane, natural gas, out of the ground and stripping the hydrogen from the carbon, emitting the carbon into the air as carbon dioxide, and then combining that hydrogen in a process called Haber-Bosch with nitrogen from the air. Then there's blue ammonia, a similar process, except instead of emitting the carbon dioxide, it's captured.

Green ammonia is different. Green ammonia is electric ammonia, made from renewable power. We take water and renewable power and use the renewable power to separate the hydrogen from the oxygen. We're emitting oxygen, not carbon. Water, renewable power, wind, solar, hydro, and air make green ammonia.

Why call it a "chemical battery"? What problem is it actually solving for renewable power?

Green ammonia is a chemical battery, and all the things you would use a battery for, both big and small, are the reasons you would use green ammonia.

A challenge of renewable power is its intermittency. The wind's not always blowing. The sun's not always shining. Renewable power, to fulfill its expectation, requires some form of battery.

"A challenge of renewable power is its intermittency," says Joel Moser.

Traditional batteries, heavy metals, require mining, which is environmentally damaging and expensive. Ammonia is a chemical battery made from water and air.

If you could bottle the wind, or bottle the power of the sunlight, that's a cool thing. And that's what ammonia is. It takes renewable power to a place where the wires can't go, like on ships, and potentially planes and trucks and cars. It's a chemical battery.

Is it safe to produce, store, and ship at scale?

It's very stable. It's safe to transport. Of the 200 million metric tons of ammonia produced and used each year, about 20% of that moves across the ocean in ships.

Ammonia is toxic. If you took a great, big, deep breath of ammonia, it would probably kill you, or it would injure you meaningfully. But in the 100 years that synthetic ammonia has been produced and used, there have been very few industrial accidents.

Petrochemicals, petroleum fuels are flammable. Hydrogen's explosive. Ammonia's toxic. They all have issues around their use.

The global shipping industry has begun the process of converting to ammonia as a fuel. Many ports of the world have ammonia storage, and people don't even know it. They call it fertilizer.

So it's got a 100-year history of safe use and handling.

Where does green ammonia get used first, and where is demand headed next (shipping, aviation, power)?

The first use of green ammonia is probably going to be the simplest application: replacing conventional ammonia with green ammonia in countries imposing low carbon standards on industry. Hands down, the latter part of this decade will already be happening.

Ship engine companies have developed ammonia-fueled ship engines, and people are now fabricating ships which will sail on ammonia. Since ammonia is a gas and goes up, and it's toxic, the fuel will likely be stored above deck, as opposed to bunker fuel, which is stored below deck.

Hydrogen is a feedstock to ammonia, and ammonia can be cracked back into hydrogen. It's more cost-effective and safer, if you want hydrogen as your end product, to convert it into ammonia, ship it, and then crack it back into hydrogen. Hydrogen and ammonia, in a way, are part of the same industry.

AI doesn't need oil. It doesn't need gas. It needs electricity. Renewable power is an easy, ready form of electricity. It is intermittent, but that intermittency can be addressed. Currently, it's addressed with baseload from conventional power. In the future, it can be addressed with baseload from ammonia. AI, far from being the enemy of renewable power development, can develop with renewable power side by side.

What's the single biggest misconception people have about green ammonia, or renewable energy more broadly?

That it only can exist when subsidized. Simply not true. It is often the least expensive form of energy that can be stood up.

The fastest power that can be stood up is renewable power, much faster than conventional power or nuclear. Nuclear is a decade. Even small modular reactors are most of a decade. Solar can get up in a year.

The only reason it's been adapted so quickly is because the subsidy has encouraged its adaptation. But there's straight up economics for renewable power.

What's the one thing you wish more people understood about renewable energy and the role ammonia can play in it?

Two decades ago, we started seeing pictures of windmills on milk cartons. It was a little cartoonish, but it was a very good way to educate the public about the meaning and significance and value that renewable energy can play. Most people get it. 

What I do is a little more obscure, but it's completely connected. The potential of renewable power will not be realized without a chemical battery, without ammonia, or perhaps some other hydrogen derivative. But I'm betting on ammonia.

I wish the public understood a little bit more about energy transition, about energy abundance, and about filling the gaps that renewable energy needs filled, and the role that ammonia can play. I wish it had a more interesting name as a chemical. It's not just me. It can help solve a problem for humanity.