Exciting Developments A Hydrogen And Ammonia Pilot Plant In Minnesota

How about ease/cost of storing hydrogen vs. ammonia? I’m thinking along the lines of deep grid backup for the few times a year that sunshine and wind are limited.

And, since we seem to have some knowledgeable people in the conversation, how about laying out the efficiency and cost numbers for various electricity -> hydrogen/ammonia -> electricity so that we can compare to the cost of other storage technologies.

First, this article isn’t about ammonia fuel – the University of Minnesota project is about producing ammonia on a small scale, locally, with renewable power and no carbon emissions. I feel bad for diverting the conversation to ammonia fuel, because the commissioning of the Wind-to-Ammonia plant should be celebrated on its own merits.

For a local farming economy, like Minnesota’s, this is a big deal: although per ton production costs may be marginally greater than for major industrial ammonia plants, the cost to the consumer (the farmer) will be lower because they avoid the distribution costs – and reduce long-term price increase / delivery risks.

Example delivered costs per ton of ammonia (based on natural gas consumption, not specific to this Wind-to-Ammonia project):
– Small-scale distributed: $154 ($15 of which is distribution)
– Typical Gulf producer: $198 ($65 of which is distribution)
– West Canadian producer: $244 ($120 of which is distribution)
[from Glen Buckley, ex-CF Industries, slide 27 of his paper on Distributed Ammonia Production economics: http://nh3fuel.files.wordpress.com/2012/10/buckley-glen.pdf

Add to the equation the fact that this Wind-to-Ammonia model is designed to monetize stranded/curtailed power, and the economics are better. This is excess power – they estimate that only 10% of the power from the turbine will be used to produce ammonia.

Second, to say ammonia fuel makes “zero” sense is bad maths. It makes some sense, in some circumstances. A few bullet points would be:
– ammonia is more dense than hydrogen: it contains about three times as much hydrogen energy than hydrogen by volume (that would be with ammonia at atmospheric pressure, and hydrogen at 10,000psi).
– ammonia is not as dangerous as hydrogen: ammonia isn’t flammable (at least, not nearly as easily as hydrogen, and please don’t confuse it with ammonium nitrate), ammonia doesn’t need to be stored at high pressure (ammonia is stored at around 100psi, but hydrogen is stored at 2,000psi or more), and ammonia is very smelly, so there’s a built-in early warning system for leaks (noticeable odor at 5ppm, and becomes hazardous to our health at 300ppm) – if there’s a hydrogen leak, you won’t know about it. So much ammonia fertilizer is used globally (about 200 million tons every year), and has been for so many decades, that the global health and safety regulatory system, and training, for ammonia is well established.
– ammonia is more easily (hence cheaply) handled and distributed than hydrogen for a few reasons: hydrogen embrittlement of steel (piping requires expensive materials), existing ammonia infrastructure and delivery networks, losses in storage and distribution (put a ton of ammonia in a tank and come back next year – there’ll still be a ton of ammonia in there) – plus the density issue mentioned above, which reduces cost of transportation significantly.
– ammonia is very easily “cracked” back into hydrogen. This can be done on-board a car, or on a much bigger scale for a turbine or fuel cell generator.

When the costs of making-distributing-cracking ammonia are less than the costs of distributing hydrogen, ammonia will be a good solution for getting around some of the problems we’ve had establishing a successful hydrogen economy.

So, ammonia fuel is not the panacea for all fuel requirements – but can it make sense? Yes, absolutely. There’s plenty of space for different clean fuels in the world.