It was a bit sad to read that many South Aussies still want to push the Nuclear power option for South Australia when all evidence points to it being be a very expensive and unnecessary proposal. We do not have the necessary knowledge base or infrastructure for such a project and could not possibly have a plant operational for at least twenty years. Similarly, nuclear subs are not a good option for Australian waters and a poor plan for Australia.
So, what instead? The cheapest power generated at the moment is solar at about 2c per kwatt hour (compared to 20 or 30 for nuclear) which is why solar is being pushed by many. If you set up your industry next to a solar power provider with no poles and wires or admin costs, power would be dirt cheap while the sun shines. Mike Cannon-Brookes, one of Australia’s richest young fellers, is pushing a huge solar power installation in Central Australia and exporting its power via a DC (direct current) line to Singapore, so I guess he thinks it is a good idea and a big part of the future for us.
First the DC current bit. Our grid is set up for large scale AC (alternating current) generated by big steam turbines. It is a lossy system, with a large amount of energy wasted in transportation (high voltage power lines). If you are interested you can read up about the fascinating War of the Currents between Thomas Edison and Nicola Tesla in the 1880s and 90s. Tesla won because it was easier to convert AC between high and low voltage in those days. Now it seems that a comprehensive DC system could act as a storage system as well and maybe a better option.
Which means we need to have a good look at how power is distributed over the next hundred years or so. It needs major government planning rather than allowing it to grow ad hoc. Solar creates direct current naturally, while nuclear is still mostly used to turn steam turbines and AC.
The other big elephants in the room are storage and transport (or mobile fuels). The best options for storage are the simple physical ones like pumped hydro where water is pumped uphill when there is excess energy, stored in a dam and allowed to fall back down again creating AC electricity. It may not be the best environmental option though.
Batteries are the next best and they store and supply DC. While lithium ion are our most effective batteries at the moment, I think it a waste to use them for electricity grids. They are brilliant for small scale storage (phones, tools and even cars) where their light weight is handy. Grid storage does not need light weight but could do with longevity. Vanadium flow, sodium ion, zinc bromide batteries and heat storage systems (TESS) are all a better bet for storage where weight to power ratio is not so important. Overall energy loss is the big issue.
We also need long term chemical storage. Gas and oil have always been good at this. If you leave your electric and petrol vehicles sitting in storage for a few months the petrol one will be ready to fire up straight away but you electric one will require a charge. During major catastrophes for example it would be good to have a mobile power backup rather than rely solely on batteries, electricity generation and grid connection.
In Australia we have plenty of natural gas and the industry is relatively well controlled and managed. We have little home-produced oil and little refining capacity, relying on other countries to supply us with a usable product. Most of this is shipped through the Great Australian Bight coming from the Middle East and Singapore. If Australia is serious about our security and safety it would be great to use our gas as our major transport fuel and reduce our reliance on overseas fuels.
Electric cars are a great innovation but require us to get rid of our current vehicles completely and manufacture new ones with different materials (lithium, aluminium, copper). The average age of a car in Australia is about 11 years, about the same as the life of a lithium-ion battery. It will be quite a while before all Aussies have electric vehicles. Whereas we could convert all of our transport to some sort of locally produced liquid / gas fuel almost immediately.
Hydrogen is likely to be the base for this local fuel system and with any luck be produced 100% sustainably in the near future. Our best options at the moment are methane (natural gas), LPG, methanol (from gas), ethanol (from plants), hydrogen and ammonia.
The cheapest hydrogen currently comes from natural gas with no carbon storage at about $1 per kg and the most expensive from solar electrolysis at about $4. I am sure we can get the electrolysis costs down considerably with scale of production, and this is the economic issue at the moment. Why not move quickly and make the process more sustainable as we can. Surely it is better than importing oil based products.
Hydrogen does have some physical issues as well including embrittlement, where metals become brittle after exposure to hydrogen. Also, the tiny hydrogen molecules escape more easily than other gases. If significant quantities reach the ozone layer, we are in for trouble. A better storage system is to convert it to ammonia (NH3) using nitrogen from the air. Burned under ideal conditions it produces nitrogen and water.
My favourite for a long term liquid transport fuel is ammonia.