Everyone has heard of the problem of fossil fuels but what exactly is the issue here? Fossil fuels have been this planet’s main source of energy since the dawn of the industrial age. Fossil fuels including gas, coal, oil and shale gas are energy resources formed over millions of years from the decomposition of dead animals and plants buried underneath sediment and rock.
Problem 1: Extraction. Coal and the like are now are becoming less and less accessible and the ways of extracting are becoming more and more destructive. Case in point: hydraulic fracking. This is a process where high-pressure water is directed at shale rock to release the gas from inside. It uses huge amounts of water, can potentially release dangerous chemicals into the water table, and has also been suggested that it causes small earthquakes.
Problem 2: Non-renewable. Fossil fuels are non-renewable resources meaning there is only a finite amount of it on this planet. The cost of this type of fuels will only increase as it becomes scarcer. So unless you know of another place off this world to go and get some, we will run out at some point in the not-too-distant future.
Problem 3: Pollution. The burning of fossil fuels releases dangerous chemicals such as dioxins, oxides of both nitrogen and sulphur and heavy metal particulates into our atmosphere (each of which carry health risks). In addition, carbon dioxide (CO2) is also released with fossil fuel combustion contributing to the greenhouse effect (the trapping of the sun’s warmth in the lower portion of the Earth’s atmosphere).
With that being said, why isn’t more being done to find a better alternative? There have been inroads made in the area of renewable energy including solar and wind power but one very promising area of research is ammonia. Yep, that stinky stuff that your grandma used to clean her kitchen floors with or the farmer down the way uses to fertilize his fields. That stuff. This chemical might not immediately seem like the solution to our energy needs. It is smelly and caustic but it does pack a wallop of energy. It has an energy density that is nearly double that of liquid hydrogen (that other clean energy fuel everyone is talking about) and is easier to ship and distribute. Many see this as the wave of the future. Research is being conducted around the world and Australia in particular is looking to lead the way in this ammonia revolution with their government awarding millions in grants and loans to ammonia energy projects.
Science content imminent: ammonia (NH3) is a colourless, pungent gas composed of hydrogen and nitrogen. It is the simplest form of these elements and is the starting component for the production of many nitrogen-based compounds. Its major use is as a fertilizer and companies worldwide produce a $60 billion worth every year. Plants need nitrogen and ammonia can be applied directly to the soil from tanks containing the liquefied gas. It is used in the textile industry, in various metallurgical processes, as a coolant (it used to be used as a refrigerant and many large industrial facilities and places like hockey arenas also use it as a refrigerant), and as a household cleaner.
Ammonia made its first introduction as a fuel for public buses in Belgium in the 1940s. Emeric Kroch developed an ammonia/coal gas hybrid motor that helped keep public transportation humming throughout the diesel shortages of the Second World War. This fleet of buses logged thousands of kilometres without difficulties.
Ammonia has a high octane rating (about 120) so it can be used in high compression engines. It does have a low energy density per litre; about half of that of gasoline, but as we have already discussed, it is much better than hydrogen. You would have to fill up 7x more with hydrogen as you would ammonia. The emissions from an ammonia-burning engine are nitrogen and water vapour. Here are the not-so-good characteristics. It is listed as a caustic substance so you would not want to inhale it (it is a huge breathing hazard for humans) or get it on your skin. It is also an explosion and fire hazard, so before it is widely adopted they will have to work out the handling and safety side of things. It is harder to contain than most fossil fuels. It would be great if they could figure out how to generate it in situ so people are not carrying pressurized fuel around. Assuming they crack the safety and handling side of the equation, ammonia fuel would be great for the planet. It is less dangerous to the environment than gasoline or diesel and overall, it is a green fuel.
Now, production of ammonia is not as green; at least as of yet. The production currently done by the use of the Haber-Bosch process involves extracting a source of hydrogen gas from natural gas or coal by utilizing pressurized, super-heated steam (which leaves CO2 behind). The nitrogen can easily be removed from the air but the melding of hydrogen and nitrogen consumes more fossil fuels and generates even more CO2. Current ammonia manufacturing consumes 2% of the world’s energy and generates 1% of its CO2 emissions.
Reverse fuel cells can solve most of the problems associated with ammonia production. They can use renewable power to make ammonia from air and water. In these cells water reacts at an anode (the electrode where current flows into) to make hydrogen ions which would migrate to a cathode (and the electrode where current flows out) where they react with nitrogen taken from the air to form ammonia. This reaction is quite efficient but slow and as of now, the yields from this type of process are modest but with more money and time being invested into this research, the fuel of the future may just be ammonia.
–Janice Willson
References:
https://www.britannica.com/science/ammonia
https://nh3fuelassociation.org/introduction/
