AMMONIA FOR NEOPHYTES; CLEAN ENERGY ALTERNATIVE

• David White; Published on June 28, 2017

A primer on the energy carrier and storage tech that isn’t talked about.

IT’S NOT SOMETHING MOST PEOPLE KNOW ABOUT, but ammonia—the chemical additive that cleans your windows so well—will have a significant place in our transportation and energy future. Since its introduction in 1913, the industrial synthesis of ammonia has transformed agriculture and civilization. Ammonia-based fertilizer, a carrier of nitrogen, has exponentially swelled crop yields, redeeming millions of human lives from starvation across successive generations of the 20th century. From 1850 to 1900, world population grew by 400 million. The challenges of overpopulation notwithstanding, that growth now happens every four years, largely because vast numbers of people who would have otherwise died of starvation, didn’t. Early 20th century scientists Fritz Haber and Carl Bosch, inventors of the ammonia synthesis process and Nobel laureates, are jointly credited with preserving more lives than anyone in human history: 2.7 billion people, one-third of the world population, are alive today because of them.

Two hundred million tonnes of ammonia are produced annually. Some goes into the refrigerant, electronics, industrial explosives and cleaning products; but 80% of it makes the fertilizer that feeds half the world. By 2030, global demand is projected at 300 million tonnes merely to fulfill its current roles. As will be detailed shortly, ammonia has an even greater role to play in our energy future which will require much, much more of it. For this to happen, a historically entrenched aspect of ammonia production must be overcome. 

“Brown” Ammonia

Ammonia is comprised of nitrogen and hydrogen. Its chemical structure?NH3?denotes one nitrogen atom bonded to three hydrogen atoms. The Haber-Bosch process fixes nitrogen to hydrogen under heat and pressure. Nitrogen for the process is drawn from the air around us, but hydrogen is found in compound molecules with other elements, notably hydrocarbons. To obtain the pure hydrogen needed for ammonia synthesis, you basically have to make it. The dominant industrial method extracts hydrogen from coal and natural gas which also releases the carbon in those hydrocarbons into the atmosphere. Therein lies the challenge. Not the ammonia synthesis itself, but the isolation of hydrogen needed for synthesis releases 2.8 tonnes of carbon into the atmosphere for every 1 tonne of ammonia produced. That’s nearly three times more carbon than ammonia! This “brown” ammonia isn’t really brown, but making it puts lots of brown stuff into the air (which really isn’t brown either, but that’s a different article). At present production levels, “brown” ammonia accounts for 1.44% of global carbon emissions. That may not seem like much, but it’s significant enough to place “zero-GHG ammonia production” on the list of 55 technical objectives identified by Bill Gates’ Breakthrough Energy Coalition.

Zero-GHG Ammonia

Fortunately, there is another process, known since 1800, for isolating hydrogen without any carbon byproduct. You start with water. Passing an electric current through water (electrolysis) essentially splits the H2O molecule into hydrogen and oxygen gases. This was the method used early in the last century, abandoned later when cheaper, fossil sources became standardized. Cognizant of the impact of carbon emissions on the environment, this tried and a true zero-GHG process is now being revived and optimized. Yet doing so presents still another challenge: electrolysis requires a lot of electricity. To deliver a truly “zero-GHG” product, each step of production must be greenhouse gas free, including the power to run it. So the final key is actually the first step in the process: energy from renewable sources. By obtaining hydrogen from water and electricity from renewables smartly purchased, a purely “green” ammonia can be produced at a cost competitive with “brown” ammonia.

The Other Hydrogen

Thus far, I’ve discussed only the agricultural use of ammonia based on its nitrogen content. It is, however, ammonia’s hydrogen content that holds a profound future impact on human society and planetary systems. Often referred to as “the other hydrogen,” ammonia contains 50% more hydrogen by volume than hydrogen itself. And hydrogen is “slippery.” Its tiny molecule has no viscosity—no resistance to flow. In the gaseous state, hydrogen will leak through hoses and escape through microscopic fissures. To liquefy hydrogen requires extreme cryogenic temperatures, achieving which consumes about 30% of the energy hydrogen holds, slashing its overall efficiency. But bonded to the much larger nitrogen atom, ammonia is easier to contain and to liquefy, thereby readily stored and transported. At atmospheric pressure, ammonia becomes liquid at a relatively mild -33 °C (-28 °F), compared to the extreme -253 °C (-423 °F) required to liquefy hydrogen. For transport, liquid ammonia is maintained at ambient temperature and 10 bars (150 psi), about that achieved by a common bicycle pump. Whereas hydrogen can only be transported as a compressed gas because no pressure is sufficient to keep hydrogen in a liquid state.

Essentially, ammonia is a convenient way to move the energy of hydrogen from here to there, from point of origin to point of use. Thanks to its decades-long utility in agriculture, ammonia has a global shipping, storage, distribution, and safety infrastructure already in place. Existing natural gas and propane infrastructures can also be adapted. While ammonia is not flammable or explosive, it is toxic. Conveniently, humans detect its distinct odor in concentrations as little as 1 ppm, and being lighter than air, it dissipates quickly if released. Studies conclude that general handling of ammonia would be at least as safe as gasoline or propane is today.

Markets Beyond Agriculture

As a carrier of hydrogen, “green” ammonia has vast and diverse downstream applications in the energy and transportation sectors. As a gasoline replacement, ammonia combustion was pioneered in Norway as early as 1933 and successfully ran Belgian buses during World War II when diesel was scarce. Today’s cars and trucks can run on an emulsified blend of 90% gasoline and 10% ammonia just as they do on E15. With some modification, late model vehicles can be outfitted with a dual fuel supply, permitting up to 80% ammonia combustion and plummeting each vehicle’s carbon emissions by the same considerable amount. Concept cars have demonstrated 100% ammonia operation with no loss of performance emitting only nitrogen and water vapor from the tailpipe. The present gasoline distribution infrastructure can be adapted to deliver ammonia right down to the pump level.

Ammonia is also complimentary with advances in electric vehicles. It can be converted on-board back into its hydrogen component for use in proton exchange membrane fuel cells (PEMFC) or be fed directly into solid oxide fuel cells (SOFC) where it reverts to hydrogen within the cell stack. The heat generated by this decomposition actually supports the operating temperature of the fuel cell. Additionally, ammonia provides the ideal zero-carbon combustion fuel for EV range extender engines to recharge lithium battery packs while in transit.

In energy, zero-GHG ammonia is one of a half-dozen feasible schemes for energy storage, and the lowest-cost technology for large-scale storage longer than one day. More compact than others, it is the only renewable energy vector able to be transported from one place to another. Ammonia packs twice the energy density of lithium batteries by volume and 10 times by weight. In power generation, non-polluting “green” ammonia can replace natural gas and diesel fuel in turbines and generator sets. Its stored chemical energy is converted into stable, zero-carbon, grid-scale electricity avoiding or balancing the intermittency of the wind and solar.

Fulfilling new roles in transportation and energy, ammonia ticks off another five boxes on Bill Gates’ list:

• Low-GHG liquid-fuels production—non-biomass
• Low-GHG gaseous fuels production—H? and CH?
• Low-GHG, reliable, distributed power solutions
• Ultra-low-cost electricity storage
• Fast-ramping, low-GHG power plants

Going Mainstream

Although rarely discussed in policy-making or public forums in America, “green” hydrogen and ammonia are gaining ground in the rest of the world. The technologies are increasingly championed by leading companies and research institutions:

• In Netherlands, Dutch utility Nuon Energy and the Delft University of Technology are studying Power-To-Ammonia scenarios at Nuon’s 1.2 GW Magnum combine cycle power plant. Participating in the research are long-standing industrials OCI Nitrogen and Proton Ventures.
• Australia has vast potential for solar and wind power in a land mass comparable to the continental United States, but little use for it with a population of just 24 million. Siemens Pacific, which generates 30% of Australia’s energy, sees that potential realized as a future export commodity shipped to world markets as ammonia. Projects in discussion right now would cover 10,000 km2 (~3900 sq mi) in solar farms producing 500 GW of energy and 1 million tonnes of ammonia every day. Japan and Germany are in the queue.
• Outside the city of Mainz, German utility Stadtwerke Mainz AG has collaborated with RheinMain University of Applied Sciences and industry partners Linde Group and Siemens AG to construct the largest renewable hydrogen facility to date. EnergiePark Mainz connects power from a nearby wind farm to state-of-the-art, megawatt-scale electrolyzers able to react in milliseconds to power fluctuations, producing enough hydrogen for around 2,000 fuel cell cars.
• Siemens and Oxford University are taking the process two steps farther at Rutherford Appleton Laboratory in Oxford—adding ammonia synthesis and energy regeneration to wind-generated power and hydrogen electrolysis. Their project will examine two different electrolyte chemistries in hydrogen electrolysis and lower pressures and temperatures in ammonia synthesis. Fifty percent funded by Innovate UK (a quasi-government funding agency), the multi-technical facility accelerates research and optimization of the entire round-trip process, from variable renewable power to chemical storage to stable grid power.
• Japan has announced a national “hydrogen society” initiative with plans to use the 2020 Tokyo Olympics to showcase its newly installed hydrogen infrastructure to the world. The Tokyo Metropolitan Government has committed ￥40 billion (348 million USD) toward hydrogen homes, buses, cars, refueling stations and Olympic facilities. Denmark, Iceland, Norway, and Netherlands have related hydrogen initiatives.
• Responding to calls within the maritime sector for “alternative marine fuels which do not yet exist,” University Marine Advisory Services (UMAS [UK]) is investigating how ammonia can support the industry's carbon reduction goals. The objective is to transition away from dependency on heavy fuel oil, the sludge left over when other petroleum products are refined out, and most polluting of all fossil fuels. Eliminating HFO from shipping will reduce global carbon emissions by 2.3% and sulfur dioxides by 8%. Naval architects at C-Job (NL) are advancing these concepts from calculator to drawing board—designing energy storage and power generation systems that could lead to the world’s first ammonia-fueled marine vessels.
• All major electrolyzer manufactures are gearing up to serve the nascent industry. Until recently, only NEL Hydrogen (Norway) offered electrolyzers upwards of one-megawatt nominal power (>150 Nm2/hr H2 output). Now that category is expanded by new entries from Proton On-Site (USA), Siemens AG (Germany), ITM Power (UK), Teledyne Energy Systems (USA), and Industrie Haute Technologie (Switzerland). All are boasting dynamic response to the power fluctuations of renewable energy sources and preparing for installations up to 100 megawatts.

As you see, a lot is going on under the surface. Zero-GHG ammonia is about where wind and solar were in 2005. When it breaks into the public eye, the common stock will be gone and the “A” rounds closed. Positions will come at a much higher price. For investors, now is the time to look seriously at this next big energy play. For the rest of us, those self-driving, zero-carbon, individual mass-transit pods of the next decade may well end up running on window cleaner instead of batteries. ??

With thanks to Barrie Pittock, Donald Gillespie, Casey Stack, Jack Robertson, David von Hippel, Darrel Smith, Kent Anderson, John Mott, John Holbrook, Norm Olsen and Trevor Brown.

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David White is principal at RESEARCH STRATEGY CONTENT, a market research, strategic partnering and brand consultancy focused in CleanTech, Clean Energy, Carbon Reduction, BioTech, Nutraceutical and Life Science industries. 

For additional CleanTech/Energy Efficiency technologies please contact [email protected]