Last month I had the opportunity to reflect on “Ammonia’s Role in the Hydrogen Society.” This was the title of a speech I gave at the Ammonia Energy International Workshop in Tokyo. The Workshop was held on January 25 by the Energy Carriers initiative of the Japanese Government’s Strategic Innovation Promotion Program (SIP) as it moves toward its terminal date of March 31, and as the Green Ammonia Consortium, which grew out of the Energy Carriers program, prepares for its official launch in the same time frame. The key takeaways from my speech are that ammonia is widely seen as a contributor to the viability of hydrogen energy, but the extent of its potential role is not appreciated.
The research for my speech leaned heavily on reporting we have done for Ammonia Energy, both on the way the “hydrogen society” is developing and the way ammonia energy concepts are developing within it. The information compiled led me to four conclusions.
- 2018 was a watershed year for the hydrogen economy as shown by the number and significance of reports issued on the topic.
Many public- and private-sector organizations issued reports in 2018 on the viability of hydrogen as an energy vector. One group of publications, from Australia, the European Union, France, the Northern Netherlands, and the United Kingdom, considered implementation of a complete hydrogen energy economy in a given country or region. Another group considered hydrogen as a constituent in the energy regime of an industry or economic sector. For example, a report issued by the Energy Transitions Commission, a body composed of “leaders from across the energy landscape,” considered the possible role hydrogen could play, per the report title, in “Reaching Net Zero Emissions from Harder-to-Abate Sectors by Mid-Century.” Most conspicuous in this regard was the maritime industry, which produced at least four reports in which hydrogen is prominently featured as a sustainable fuel. In total, I reviewed 16 reports that were featured or at least mentioned in Ammonia Energy.
All of the reports conclude that hydrogen can be a viable element in a sustainable, post-fossil energy economy – as long as key stakeholders embrace the challenge. The Web summary of the report from the U.K.’s Committee on Climate Change is typical: Hydrogen “is a credible option to help decarbonise the UK energy system but its role depends on early Government commitment and improved support to develop the UK’s industrial capability.”
- Ammonia is now seen almost universally as an important contributor to the hydrogen economy, a consideration that abetted hydrogen’s watershed year.
Fourteen of the 16 reports I reviewed included explicit, positive mention of ammonia as an energy carrier. (The two that didn’t failed to cite ammonia at all except as a chemical commodity.) The prevalent view is that ammonia will likely prove the best option for hydrogen transport and storage. The Foreword of Australia’s National Hydrogen Roadmap contains representative language: “Easy conversion from gaseous hydrogen to liquid ammonia offers a simple storage and transport of safe, high energy density liquid fuel using existing global infrastructure.”
- However, only a few of the organizations studying the hydrogen economy express awareness of ammonia’s potential end-use applications.
The reports generally start with a ringing endorsement such as this from the French report: Hydrogen may “become a major solution for our energy mix of tomorrow, first by enabling large-scale storage of renewable energy and thus gradually replacing fossil and nuclear energy in addressing the intermittency of solar and wind.” “Hydrogen” in this statement can be most simply understood as a reference to the diatomic element H2. But in many of the reports, the term “hydrogen” includes other molecules that contain the element. A passage from The Green Hydrogen Economy in the Northern Netherlands is representative: “Hydrogen can be compressed or liquefied and can easily be converted into a liquid chemical/fuel, such as ammonia or methanol.”
In fact, a spectrum is apparent when looking across reports. At one end “hydrogen” means hydrogen, full stop. At the other, it is a generic signifier meant to evoke a renewables-based economy whose fuel molecules cycle benignly as they accept and discharge energy. The report that embodies the most capacious definition is probably the Royal Society’s Options for producing low-carbon hydrogen at scale. Here, after the potential of ammonia “as a promising long-term hydrogen transport and storage option” is acknowledged, it is highlighted as “a versatile fuel that can be used directly in high-temperature solid oxide fuel cells, cracked for low-temperature fuel cells, and partially cracked for combustion in turbines and internal combustion engines.”
The inclusion of ammonia’s end uses is not a minor point. Every conversion of an energy carrier from one compound or phase to another saps energy and adds cost. The impact of an ammonia-to-hydrogen step toward the end of the value was recently quantified by the SIP and shown to be significant. Foregoing the step can make a meaningful contribution to the overall cost-competitiveness of hydrogen energy.
- With growing understanding of ammonia’s potential, the next generation of hydrogen reports should acknowledge the possibility of a dominant role for ammonia in the hydrogen energy economy.
During my preparations I also went back to the U.S. Department of Energy’s ARPA-E REFUEL program. REFUEL provides a different perspective on the possible role of ammonia in a hydrogen energy economy. Its conceptual foundation is the idea of carbon-neutral liquid fuels (CNLFs), which, according to the program’s home page, are “made by converting molecules in the air (nitrogen or carbon dioxide) and hydrogen from water into an energy-carrying liquid using renewable power.”
The program issued a Funding Opportunity Announcement in April 2016 and announced recipients of funding awards in December 2016. Of the 16 winning projects, 13 took ammonia as their CNLF of interest. (Two are focused on dimethyl ether, one on ethanol.) Ammonia’s strong performance in the funding competition was certainly notable. But it was the research objectives of the selected ammonia projects that were relevant for my speech. If successful, each of the 13 projects will tend to increase the size of ammonia’s role in a hydrogen energy economy. One is focused on polymer electrolyte fuel cells, which could find application as power plants for vehicles. Two are focused on direct ammonia solid oxide fuel cells, which could find application in combined heat and power systems in the built environment. Three are focused on the conversion of ammonia to high-purity hydrogen. And seven are focused on converting electricity to ammonia. While six of these include hydrogen production as an intermediate step, the seventh seeks to “develop an advanced solid oxide fuel cell system capable of generating ammonia from nitrogen and water, and renewable electricity.”
These projects bring into view a scenario in which ammonia is the dominant fuel species: created directly from electricity, transported and stored in its native form, and used directly to produce heat, light, and motion. In this scenario, hydrogen would be limited to discrete applications, of which the most prominent would likely be powering hydrogen fuel cell vehicles (at least as long as HFCVs are able to compete with vehicles powered directly by ammonia, and those powered by batteries).
In my speech, I did not assert that the “ammonia dominance” scenario is a foregone conclusion. Clearly it is just one of many that could come to pass as we work toward a sustainable energy economy. But I did say that proponents of hydrogen energy across the board would do well to know that this scenario exists and to consider it seriously. Because we all wish for the hydrogen energy economy to come into being as quickly as possible; and the best way to make that happen is to design it for optimal cost, safety, and ease of implementation. And that is the whole point of ammonia energy.
2018 Ammonia Energy Posts on Hydrogen Viability Reports
February 22, 2018: Royal Society Releases Low-Carbon Hydrogen Briefing
April 19, 2018: P2X, Ammonia Highlighted for Long-Haul Road Transport, Shipping
August 9, 2108: Hydrogen Plans Appear, But Where is Ammonia?
September 13, 2018: Ammonia Coming on Like Gangbusters in Australia
December 6, 2018: The Most Efficient Way to Decarbonize the Shipping Sector
December 20, 2018: Ammonia Featured in Hydrogen Europe Roadmaps Report