Large-sale adoption of ammonia and other renewable energy for transportation and industry is the key to effective change

Ammonia, Hydrogen, and Methanol—How Do They Compare on Efficiency and the Environment?

by kirkcoburn
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I have been thinking about the energy transition since 2010 (in other words, I started actually putting my money to work trying to solve the world’s energy problems). I don’t mean as in, ‘Will those Ford and Chevy EV trucks really get the distance that the ads say they do?’ I mean like industrial size problem solving—the kind that can power airplanes and container ships. Be honest—have you ever really considered how your German sedan gets here (the SUVs are made in the US, for the most part)?

Alternative Fuel Sources

One thing that drives me absolutely insane is when somebody tells me that a product is “organic,” like that gives it some sort of seal of approval from Mother Nature. Please let me remind you that anything that derives from the earth is organic. But it’s not necessarily all that great an idea, at least for human consumption. Cyanide, for example. And, you know, mercury and arsenic. While fossil fuels have admittedly had a great run and will so for the foreseeable future (do you watch our Podcast on Digital Wildcatters #BDE? You should. We debate these topics with data and a lot of emotion), the transition to alternative and cleaner sources is ready… methanol and ammonia are potential cleaner options that could become the next great fuel source. And yeah yeah yeah…I have heard this story a lot…but I have to be careful by not being too optimistic while also not throwing away the baby with the bathwater.

Fuel Density

I could spend a lot of time here explaining fuel density, but it’s not really the topic at hand. In the simplest terms, fuels all have varying degrees of density: “equivalent energy released by combustion.” Density is measured in two ways, unit of mass or unit of volume. Today, we’ll focus on volumetric density—how much fuel a storage tank can hold and how far it will propel a given vehicle. I mean, a dead battery on the highway is a nuisance. But a dead battery over the North Atlantic, not so much. 

Gases are the highest quality fuel, followed by liquids, then solids. This gets wonky because gases are extremely temperature-sensitive. However, keeping a fuel storage tank at some insanely cold temperature just doesn’t scale. Hydrogen, the simplest fuel chemically, is also most dense (except for uranium, but I will discuss nuclear on a different post). 

Think about your grill. A charcoal or wood fire takes a lot longer to cook your food than propane, a liquid. If you fire up the griddle on your Viking range (which will be banned soon…smoke them while you got’em), that heats up faster than your outdoor Weber because what comes into your house is already in gas form. 

Jet fuels are combinations of kerosene and additives (antifreeze, antistatic, antioxidants, etc.) because the fuel has to withstand extremely low temps at high altitudes. In shipping, which is where the majority of ammonia as fuel is focused, Bunker C fuel (low-grade petroleum) is acknowledged as low-quality sludge, but it’s the best option for those tremendous ship engines. 

A HAM Sandwich

There’s some seriously exciting research happening globally with alternative fuel sources. Hydrogen has gotten the lion’s share of the attention (and funding), but there are other compounds that are showing at least as much promise as hydrogen. In the US, the energy bill allocated $7 billion to explore building regional “clean hydrogen” hubs all over the country. Ammonia figures into this research since that industry can hoover up 10% of the hydrogen produced every year in making carbon-neutral fertilizer and chemical manufacturing processes. 

So, what’s out there besides hydrogen? Ammonia and methanol are getting a lot of serious looks from the public and private sectors. Since ammonia is my new thing, let’s look at how it stacks up against hydrogen and methanol primarily. Then we’ll see how it compares to other options like biomass and diesel since they burn much cleaner than gasoline. 

Hydrogen vs. Ammonia

Hydrogen in its natural state has a higher density than ammonia (because there are more molecules in ammonia). But liquid hydrogen has a lower density (8.5 MJ/L) than ammonia (12.7 MJ/L). 

What this means for real-life applications is that ammonia can be stored at -33° C, while hydrogen requires a storage temp of -253° C and is a lot more flammable than ammonia. An ammonia-based fuel doesn’t need nearly as much storage space as liquid hydrogen, so ships can travel further. 

Let’s face it—hydrogen is the prima donna of renewables. It demands low temperatures only found in the solar system, the kind of high pressure usually associated with diamonds, and environmentally questionable chemical processes to be useful. So as fuel, hydrogen only scales as an industrial transportation solution. 

Your everyday garage ride doesn’t have the storage capacity for a hydrogen cell to do much good; the 300-mile-ish distance is about the limit with current technology. 

Hydrogen and ammonia will both be critical to the coming net-zero economy. After all, both have their advantages—primarily, no carbon emissions. They are already integral to heavy transportation, agriculture, and energy storage. The challenge for both vapors is to fine-tune the existing technologies to make them easier to deploy at scale. 

Methanol vs. Ammonia

Methanol (CH2OH) is another alternative fuel source. If you were around in the early 1990s, you might remember that it, along with ethanol, was touted as the fuel of the future. That came to a screeching halt when the EPA determined that methanol emissions were having a negative impact on a lot of things, from corroding older vehicle wiring and hoses to emissions toxicity and flammability. Sounds like a great solution, huh?

Well, yeah, it is worth the billions in global research that Asian and European nations are pouring into methanol. China is building a couple of methane conversion plants in Texas and Louisiana (you read that right) because all that natural gas in the region has the resources for their methanol-powered cars. 

There has been a lot of conversation in the US about cows and their methane burps causing global warming, and that’s true. But industrial methanol is produced by synthesizing natural gas into a methanol and water vapor, and there isn’t enough livestock on the planet to power a Maersk tanker from Germany to China. 

Relative to other fuels, methanol is cheap to produce, is less flammable than gasoline, and can be harvested from carbon-based materials—coal, natural gas, and biomass. MIT is currently researching using these feedstocks for mass-produced transportation fuels. Natural gas from fracking has created an abundant supply of methanol production materials. 

The problem with methanol is that because it is derived from fossil fuels, it emits carbon dioxide when burned. This sort of defeats the purpose of green energy, but the research these days is focused on making methanol from biomass or e-methanol. 

Ammonia is a more attractive fuel source than methanol in the long run. There are no carbon emissions, which is the whole point of clean energy. 

Ammonia Advantages

Tugboat (like the one being converted to use ammonia) towing a larger ship

Ammonia as fuel is getting its biggest boost from the maritime sector. The International Maritime Organization (IMO) has fallen in with the Paris Climate Accord’s goal of cutting carbon emissions by 50% by 2050. 

One ammonia-capable ship, the Kriti Future, has already been delivered to the Greek shipping line Avin International. The ship has dual fuel technology, so it can convert directly to ammonia as soon as it is available. 

Unlike hydrogen and methanol, ammonia can be made from existing renewable resources—biomass, solar, and wind—so it is intrinsically carbon-neutral. To meet the IMO goals, though, ammonia fuel may not be as green as one hoped. At the moment, the only way to create that much ammonia is through the Haber-Bosch method. But it does produce some carbon emissions.

Green production methods are in the research and development stages; with any luck, those will be scalable in the near future. 

Here’s how ammonia stacks up against hydrogen and methanol:

  • It’s cheaper than hydrogen (32%) to transport and methanol (15%) for carbon capture.
  • It has low flammability since the conditions for spontaneous ignition are difficult to create.
  • Toxicity is the key drawback, so safety systems (ventilation, water sprinkler sprays) need to be implemented.
  • It has low production, transport, and storage costs at scale.
  • Large-scale synthesis technologies are already mature.

Some Projects Are Already Underway

Amogy, a Brooklyn-based startup, has already retrofitted a John Deers tractor with ammonia fuel capacity. Their next announced venture is converting a 65-year-old diesel tugboat to ammonia power. Across the pond, Wärtsilä, a Finnish marine tech company, is testing ammonia in a marine combustion engine. MAN Energy out of Germany and Samsung Heavy Industries have partnered with other companies to have the first ammonia-powered oil tanker on the waters by 2024. That’s just a year away, if you’re keeping score. 

The biggest obstacle ammonia faces is regulatory. Because of toxicity, It’s not even legal as a fuel yet per the IMO regulations.

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