Does anyone know if it would be possible to convert an Aluminum smelter into a battery for storing excess energy from a renewable energy source?
- Jul 8, 2020 10:23 am GMT
- 795 views
I imagine, if so, the cycle efficiency might not be too good due to the necessity to keep the battery at a high temperature but this might be somewhat improved by using a super insulator such as the re-entry tiles on the Shuttle. If sufficiently insulated, the current flowing through the battery might be enough to keep the material molten as is the case with liquid metal batteries.
Beezley Energy Advisors
Member since 2012
Principal, Beezley Energy Advisors
Hi William : I am not sure of the thrust of the question. But I will offer some thoughts and you can let me know if I did not get to what you are looking for.
An aluminum smelter facility is designed to use high volumes of electricity to reduce aluminum ore into pure aluminum. Typically, these facilities have been located near massive hydro (dams) to supply the needed electricity at the lowest price possible.
Liquid aluminum metal is not a good energy storage media as it's heat content is too high, making it very difficult to store in liquid form. Instead, the liquid metal is usually poured directly into forms/sheets/bars for transport to aluminum product production facilities.
If one has a significant amount of energy available that needs to be stored, there are a variety of storage media available that can store the heat at a temperature beyond the boiling point of water over the long term, and be tapped to release their energy on demand. Beyond liquid storage options, safer storage can be found using bricks and rocks in a thermal system designed to function as a giant battery. Another way to store electricity is just to use a utility scale battery system such as flow battery, or lithium ion batteries.
Hope this helps your thinking.
Member since 2018
Director, Silverthorn Institute
For all practical. purposes, the answer is no, it can't. The commercial Hall-Heroult process for producing aluminum from a solution of aluminum oxide dissolved in molten cryolite is only partially electrolytic and not reversible. It would be more aptly labeled an "electrochemically facilitated carbothermic reduction". Aluminum plates out at the cell anode, but the cathode is consumable carbon. The gas evolved at the cathode is not oxygen but rather carbon dioxide. The reaction is carried out at conditions far from equilibrium. That's why it's not reversible.
It is possible to use pure aluminum as an energy source. Under controlled conditions, it can react with water to produce hydrogen and aluminum oxide. The hydrogen can then generate power in a hydrogen fuel cell. It's not efficient and it's not economical, but it has been considered--I think it may even have been demonstrated--as a way to produce a lot of electrical energy from a low mass of "fuel". Recycling the water from the hydrogen fuel cell would effectively create a high energy density aluminum-air battery. Such batteries could support relatively long distance electrically powered air transport. However, the overall energy efficiency would suck, and "fuel" (i.e., aluminum) would be too expensive for that application.
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