Transforming the Future of Aluminium Smelting
EnPot is a patented new mechanical technology that can be cost effectively retro-fitted to 90% of the world's aluminium smelters. EnPot breaks the restraints of the current cell design by opening up the operating energy-use window, fundamentally transforming the way aluminium smelters consume energy during the smelting process.
Aluminium smelting accounts for over 3% of the world’s total electricity use. The current problem with aluminium smelting is that the process not only requires a massive amount of electricity, but it needs it continuously to keep the electrolysis process running.
Currently the energy input of a smelter cannot be varied by much more than plus or minus 5%, meaning a smelter essentially operates at full capacity 24/7, 365 days a year, for its entire lifespan.
This current maximum-production straight jacket has a significant effect on the cost of production for individual smelters, as smelters cannot vary their energy use to match electricity price fluctuations. It also creates power supply issues for national grids seeking to generate a higher percentage of their electricity from renewable sources.
Furthermore, not having the ability to back off full production affects the dynamics of the supply and demand curves of the primary aluminium industry as a whole, and means the industry cannot respond to oversupply issues, which leads to stockpiling and in-turn to long periods of depressed prices.
EnPot gives smelter operators the ability to turn energy consumption up or down by as much as 30%* to take advantage of off-peak power prices, as well as accommodating the intermittency associated with renewable power supply. It also means production can be better matched to supply and demand.
> Learn more about what EnPot does to transform the economics of the marketplace
How EnPot Works
Making aluminium requires an electro-chemical process, where aluminium is freed from its ore via the energy supplied by a powerful electric current. This takes place at approximately 1000 °C in large, carbon lined, molten electrolyte filled pots (with less than 30°C tolerance).
Increasing production means increasing the amperage through the pot. This generates more heat, which needs to be removed from the outside of the pot faster to prevent pot failure. Conversely to decrease amperage and slow down production, you have to insulate the pot in order to keep it from cooling and solidifying. To do both before now has been impossible.
The EnPot system places up to 60 intricate heat exchangers against the side of each pot (the average smelter has 320-420 pots) and connects them to an external ducting system. The airflow to each exchanger can be varied by using a series of precisely controlled extractor fans, which allow the exchangers to either act as an air-conditioner to cool the pot, or a thermal blanket to keep the pot warm, depending on what is needed.
EnPot has been installed in a partitioned section of TRIMET Aluminium SE smelter in Essen, Germany since June 2014. By increasing or decreasing their energy use by 25%, TRIMET have shown they can become the energy bridge buffering supply and demand in Germany. Their goal is to use their smelters to give Germany a virtual battery capacity of 12GWh (approximately 25% of Germany’s current pump hydro storage capacity).
When power demand and price is high, or electricity generation is low, EnPot can be used in insulating mode to decrease energy usage below the usual design window and optimise profitability.
When power demand and price is low, or electricity generation is high, EnPot can be used in cooling mode to increase amperage above the usual design window, to maximise production and profitability.
The EnPot system installed in TRIMET's Essen smelter in Germany. Retro-fitting is non-invasive and easy to install.
The EnPot aluminium smelter conversion system can be economically retrofitted to over 90% of the smelters in the world, and cost savings can be between US$10-20m per annum for a 320 pot smelter, giving a return on investment time frame of between 0.7 years and 1.45 years.
A further significant bonus of the EnPot system is that it can be used to insulate the pots and delay the solidification of the molten liquid in the case of a serious power failure. The smelter will have up to twice the time available to prepare for a shutdown, therefore reducing insurance risk.
The Virtual Battery
“TRIMET’s trials of the EnPot technology indicate that by being able to dynamically increase or decrease our energy use by 25%, TRIMET could in fact become the energy bridge buffering supply and demand in Germany,” says Dr. Martin Iffert, CEO of TRIMET Aluminium SE.
* Not all smelters will have the ability to increase amperage without significant infrastructure upgrades. Find out more.