Is Green Ammonia the Solution to Hydrogen Transportation and Storage?

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Written by Paul Wiseman for Industrial Info Resources (Sugar Land, Texas)--For all the interest in hydrogen as an energy transition fuel because of its abundance and its relatively high energy density for a non-fossil fuel, pure hydrogen presents some practical challenges.

Hydrogen's small molecular footprint makes it difficult to tame in tanks and pipelines. Liquefying it, similar to liquefied natural gas (LNG), requires chilling to -423 degrees Fahrenheit, as opposed to -265 degrees Fahrenheit for natural gas. Alternatively, it can be compressed to 700 atmospheres. Both options are costly and difficult to maintain. For related information, see November 18, 2022, article - IEA: As Hydrogen Production and Use Grow, So Must Transportation Infrastructure.

A new report from Reuters suggests that green ammonia may be a better solution. Hydrogen-rich, ammonia (NH3) has a higher energy density than hydrogen. Ammonia, like hydrogen, is a gas at room temperature, but can be liquefied by compression to just 10 atmospheres or by cooling to -27 degrees Fahrenheit. As a liquid, it is more easily transported through pipelines or by truck or rail.

However, even ammonia faces many challenges before becoming a practical option says the report, entitled, "Green ammonia: the next frontier for clean hydrogen?" Current methods of making ammonia are highly carbon intensive. The first of the two-step ammonia process involves isolating hydrogen, 95% of which now happens by steam methane reformation from natural gas. Because that releases carbon atoms that were in natural gas (CH4), steam methane reformation "produces more carbon per unit of energy than gasoline does," the report states.

The second step makes use of that hydrogen to form the ammonia itself, using a process known as Haber-Bosch, which requires temperatures of 500 degrees Fahrenheit. In producing enough hydrogen to supply the $66 billion-per-year worldwide hydrogen market, Haber-Bosch reportedly "accounts for up to around 2% of global energy consumption and 3% of worldwide carbon emissions" says the report.

How to Green Up the Hydrogen
The challenges of industrializing green hydrogen are immense because, in the report's words, "the industry is starting from zero." Plug Power (NASDAQ:PLUG) (Latham, New York), a developer of hydrogen fuel cells, is in the process of building a 100-megawatt electrolyzer that, when completed, is expected to produce 90,000 tonnes of green hydrogen per year. Electrolyzers use water as a hydrogen feedstock, releasing oxygen as a byproduct.

Plug Power Executive Vice President Franz Roozendaal says today's average ammonia plant produces 4,000 tonnes per day, "so the scale-up which is required is huge."

Should ammonia indeed become more in demand as a fuel for transportation and industry, the green scale-up requirement will be even larger. That's because the ammonia-as-a-fuel market today is near zero with almost 100% of it being used for fertilizer and for industrial processes. If ammonia becomes a go-to fuel for transportation and for the power grid, its overall demand could require even more green-produced hydrogen and ammonia in order to meet climate goals.

At least one expert sees green ammonia demand doubling if it were used as a hydrogen carrier and as a shipping fuel. The paper quotes Ammonia Energy Association President Rob Stevens with that view. That could require an extra 200 million tonnes of green ammonia per year, which prompted Stevens to say, "We see a challenge in getting it shipped from low-cost production places to where it is being consumed."

While blue ammonia--generated from natural gas with the added step of carbon capture--is growing, especially in Louisiana, carbon capture is costly and requires plentiful underground storage. Louisiana currently leads the world in ammonia production and leads the U.S. in carbon capture.

Need for Investment
Under any color scenario, green or blue, the Reuters paper authors see an enormous need for investment. It quotes Stevens as saying that around 15 million tonnes of green ammonia capacity could be commissioned by 2030, but most of it is are in Latin America and Australia.

There also are supply-chain shortages in production of electrolysis stacks, and further development is needed on that technology in order to speed production and reduce costs.

Experts beyond this paper have noted that the Russian invasion of Ukraine created a shortage of ammonia because countries in the former Soviet Union were aggregately the world's second-largest supplier. That flow was largely stopped, along with exports of Russian oil and gas. The resulting ammonia shortage skyrocketed its costs as a fertilizer, creating ripple effects worldwide in the agriculture industry.

In light of that, any expanded use of ammonia in transportation would have to be accompanied by extensive investment in some color of ammonia in order to protect food supplies from hyperinflation.

Energy transition challenges are great, and adopting green ammonia as hydrogen carrier is no exception.

Industrial Info Resources (IIR) is the leading provider of industrial market intelligence. Since 1983, IIR has provided comprehensive research, news and analysis on the industrial process, manufacturing and energy related industries. IIR's Global Market Intelligence (GMI) helps companies identify and pursue trends across multiple markets with access to real, qualified and validated plant and project opportunities. Across the world, IIR is tracking over 200,000 current and future projects worth $17.8 trillion (USD).