“We have a well-sealed system, you don’t smell it,” says Joe Beach, reassuringly. He is co-founder and chief executive of Starfire Energy, a US-based firm that is developing a means of producing ammonia from renewable energy, air and water. But, he argues, the pungency of ammonia is actually a benefit. If there’s a leak, you’ll soon know.
Ammonia, or NH3, is nothing more than nitrogen and hydrogen, both highly abundant elements. Earth’s atmosphere is mostly nitrogen, and water is full of hydrogen. Starfire Energy uses electrolysers to split hydrogen from water and then feed it into a reactor along with nitrogen to make their ammonia.
The ingredients flow through a honeycomb structure laced with a catalyst – similar to the catalytic converter in your car’s exhaust. This device encourages nitrogen to bond with hydrogen, and liquid ammonia is collected at the end of the process.
Crucially, the whole thing can, says Mr Beach, run on intermittent renewable energy such as wind and solar. “For a conventional ammonia plant to go from cold to full output is a two- to three-day process,” he says. “For us, it’s about a two-hour process.”
Once started, the system can cycle on and off in a matter of minutes, following the vagaries of renewables. Starfire Energy aims to deliver its first commercial-scale devices, which could produce a tonne of ammonia per day, in 2025.
In general, green ammonia start-ups want to show that they can make ammonia production cleaner and easier to control. Plus, many, including Starfire Energy, hope to package the required tech in a space as small as a shipping container, so that it can be made near to the point of use – quite unlike the gargantuan Haber-Bosch plants operating today.
“We do want to make fertiliser on a small scale so we can use it more efficiently,” says Lea Winter at Yale University. Cutting the need to transport ammonia fertiliser over long-distances could further reduce emissions, she notes.
