Many people are, by now, aware of the tremendous value green hydrogen can bring to the clean energy transition (and if not, Enapter is more than happy to make the introduction!).

But mention the possibility of adding an ammonia energy carrier to the mix and you may receive a few raised eyebrows. The ammonia of cleaning products, industry and fertiliser fame? And why, you may ask, is a green hydrogen player like Enapter even mentioning this possibility?

To answer this question, we spoke with one of our pioneering industrial customers, Starfire Energy — one of the companies vying to make ammonia a major part of the green energy future but forging a different path than the big industry players.

Capturing the value of ammonia

But firstly, what is ammonia? Like hydrogen, it’s a colourless gas, otherwise known as NH3. Why is it important? The first half of the answer is this: As the world’s second most heavily-produced commodity chemical, ammonia accounts for an estimated 1.8 to 3% of global CO2 emissions due to fossil fuel-based production. 80% of this is then processed into fertiliser.

So just as with hydrogen, the colour of the gas we produce matters. In fact, the relationship is even closer – it’s also how we create the hydrogen used to make ammonia that matters.

This was something recognised by Joe and Jennifer Beach, the Colorado-based co-founders of Starfire Energy. Inspired by her husband’s work with PV technologies, Jennifer started the company in 2007 to deploy solar energy systems.

Through this, Joe soon saw the need for a renewable fuel in seasonal energy storage, transportation and heat applications. Green ammonia emerged as the best choice and Starfire developed a prototype for making this zero-carbon substance from just three basic ingredients: fresh air, water and renewable electricity.

After using a pressure swing absorption process to capture nitrogen from the air and Enapter’s modular electrolysers to turn renewable electricity and water into green hydrogen, Starfire turns to its Rapid Ramp NH3 system. The reactor combines hydrogen and nitrogen to create ammonia and can ramp up and down flexibly to match renewable energy supply.

“We see ammonia as being a major replacement of fossil fuels so we’re making modular systems for making it, as well as ways to use it,” says Beach. “We chose it over methane for distributed production as it’s much easier to get nitrogen out of air – it makes up of 78% of the atmosphere – unlike the CO2 needed for methane, which only makes up 0.04%.”

The current power-to-ammonia system creates a modest 10kg of gas a day, with Starfire mid-way through a fundraising round that would give it the capacity to offer a 100kg/day system for pilot evaluations. Beach says that success here would lead to mass-produced modular 50 T/day systems to serve a wide range of green ammonia production needs.

The multi-trillion-dollar opportunity

Prospective customers are lining up to test Starfire’s upcoming version and the demand for green ammonia production is set to grow drastically: the green ammonia production capacity needed to meet clean fuel demand for the maritime sector alone has the potential to range from 670 to 946 million tonnes per year, representing a possible 5 trillion USD market.

But why? Here we come to the second part of the story: Aside from its farming, industrial and cleaning prowess, ammonia is one of the most energy-dense substances we can create from renewable electricity — and it’s an incredibly hydrogen-dense material (18% by mass).

An ammonia energy vector has advantages for storage and transportation, liquefying at -33°C compared to -253°C for hydrogen, with one cubic metre of ammonia roughly carrying 50% more energy than the equivalent volume of hydrogen. This makes it easier to handle and much more compact, while the infrastructure and procedures for storing and transporting this renewable energy carrier are well-established.

It also explains the trillion-strong market opportunity: The above properties make it extremely interesting as a clean alternative fuel for the shipping industry, which currently uses bunker fuel – the cheapest and dirtiest fossil fuel available. Shipping was responsible for 2% of global CO2 emissions in 2019 and the sulphur discharge is also a major health hazard.

As conventional ammonia begins to turn green and the shipping opportunity looms large, big players are positioning themselves for production at far larger scales than Starfire.

For instance, the NEOM facility in Saudi Arabia will use solar and wind power to create 3,500 tonnes of green ammonia per day by 2025. A prototype energy supply vessel driven by an ammonia fuel cell, named Viking Energy, is taking shape in Northern Europe, while giant companies from Siemens to Thyssen-Krupp and Ørsted have created green ammonia facilities (or plan to), and firms in Australia and the USA are also exploring the potential for massive plants to get on board with the energy carrier before the wave of demand arrives.

This makes sense: ammonia production is normally a large-scale affair, using vast amounts of natural gas to create hydrogen and then ammonia. But even if this is instead achieved using renewables, there will still be areas where such centralised production won’t help.

Distributed modular green ammonia

The same energy density and stability that make an ammonia energy vector attractive in shipping also apply to a broad range of use cases that benefit from distributed production.

Its effectiveness as a hydrogen storage and delivery source has created new and emerging applications as varied as use in hydrogen vehicle fuelling stations, seasonal energy storage for microgrids with poor or non-existent grid connection, and even balancing of commercial power grids – in addition to the greening of conventional ammonia supply.

Beach also estimates that ammonia generation and storage for forming grid stability will be a trillion-dollar industry by 2050 – one that will depend on distributed energy storage and on solutions that can easily ramp up and down to balance out fluctuating renewables power.

Like the Enapter electrolyser modules in Starfire’s setup, the company’s modular ammonia production units are planned to be mass-produced. Systems built from the easily-transportable modules would allow green ammonia to be produced right where it’s needed and built out to deliver exactly the required amount of ammonia for the particular use case.

Although large-scale ammonia facilities will undoubtedly be important to establish ammonia as a renewable energy carrier, Beach says modular production facilities would be quick to build relative to the long construction lead-time of such centralised green ammonia plants, allowing for the rapid expansion of distributed power-to-ammonia systems.

Scaling this solution to cut back on fossil fuels mirrors the approach of Enapter, which will in 2021 start building its first mass-production plant — the next step on a similar journey. Despite (or perhaps because of) the convergence of such journeys, it seems hydrogen and hydrogen carriers like ammonia won’t be competitors but co-dependent, building on each others’ strengths to enable the energy transition the world sorely needs.

by Joe Dodgshun.