Engaging Energy

In my recent comment to NERN I said that more attention should be shown to the life-cycles of the major industrial metals such as aluminium, zinc, copper, nickel as a major source of energy savings. I’m going to go through the case study of Al to demonstrate that a metal doesn’t have to be rare to be big news.

Aluminium is a dull metal. Its uses are dull. Its geology is really dull. Its chemistry is dull. In fact its only really its processing that makes Al stand out and that’s because it is so energy intensive. You need vast amounts of electricity (for example Alcan Lynmouth has its own 420MW power station built adjacent to it) plus sources of sodium hydroxide and of fluorine (usually synthetic cryolite made from fluorspar these days) to get from the raw bauxite through semi-processed alumina to the metallic aluminium.

To give some scale; Alcan, probably the world’s single largest vertically integrated aluminium producer, ships 30 Million tonnes of raw ore a year to its refineries and it takes 4 tonnes of bauxite to produce 1 tonne of metallic Al. Global metallic Al production is between 35-40Mt depending on when you take the measurement which means that somewhere between 30 and 160Mt of material is shipped each year within the aluminium life-cycle before the metal even gets to the manufacturing stage. Of course the energy embodied in getting to metal is only one step.

UK estimates show that the difference in energy footprint between 1kg of primary production and 1kg of recycled production is 14kWh. The UK consumes around 1 million tonnes of Al per year representing an embodied energy of somewhere around 14M Mwh or 1.2M toe. Again to give some scale 4GW Drax produces around 25M MWh each year or 7% of the UK’s total consumption of electricity which implies that the amount of energy required to provide the UK with its Al needs is equivalent to roughly 4% of total electrical consumption (or 1 1/2 Sizewell B’s). Of course we don’t mine bauxite in the UK and much of the refined metal we use is produced elsewhere, so a lot of that energy is offshored to areas where we have no influence on the energy system employed. For example Australia, the world’s largest Al producer and exporter has grids dominated by coal, Guinea is a classic macro-hydro development story and former Eastern-bloc countries mostly use the Al smelter/nuclear power station combo that is also present at Wylfa on Anglesey. So we can pick our own baddies from that list
Currently the UK uses roughly 50% recycled Al, about half of which is old scrap (mostly packaging) and half industrial new scrap, but still landfills 3 billion drinks cans a year.

So that all gives some idea of the scale of the aluminium industry in the UK and the world. The thing is that there is a new technology available that could cut energy requirements of primary Al production by 40% and cuts out the Bayer pre-production process with all its nasty caustic wastes. It also allows a higher percentage of recycled Al to be used within primary production so removing a step in the recycling chain and allowing for a smaller modular smelter. Its inventors claim that Al costs would be roughly 25% of current costs (down from $2,000 to $500/tonne) if their system were commercialised. Its essentially a conventional smelting technology that uses a flux, instead of the complex Hall-Heurot process that uses electrolysis.

In itself 40% of 14Twh is not even a 1GW conventional power station, but that isn’t the point. If you can drop the cost of Al by 75% you can massively increase its use in the automotive sector effectively swapping all steel chassis parts for Al and reducing overall rolling weight by 20%+. This is where the investment really starts to kick in because you can now structure the supply chain in the same was as the steel mini-mills with manufacturing close to consumption and a high % of recycling without excessive pre-processing. All of a sudden over the life-time of a car you have dropped the embodied energy by 50% and the daily energy consumption by 20%. This is a multiplier when taken with the drop in primary processing cost. I can’t claim to know what that multiplier would be but the 1 1/2 Sizewell B’s are joined by many oil wells (or however you are powering you personal transport these days).

So swapping Al for steel in cars is a realistic prospect. It needs investment to get it going on a national scale because it requires both new car production facilities and new Al processing capacity but on an energy basis it looks a stone cold winner. The best thing is that the process is exothermic so you can recover energy off the back of the smelter and optimise the process even further than the inventors have as yet.

The process is called Thermical(tm) and is being promoted by Calsmelt and Australian company that I am not getting paid by.