>It is a very useful metal, and if it is electricity intensive to define, I wonder if it would fit the use of excess renewable electricity.
No, absolutely not. Aluminum refining, like all industrial processes at scale, takes a long time to get going and needs to run (hence be fed electricity) continuously, not just whenever the wind feels like blowing.
While it is an excellent business opportunity for electricity that is cheap because it is renewable- and why Canada produces more refined aluminum than any other Western country thanks to its electric generation being overwhelmingly renewable for the entire time it's even had a grid- it's not something you can turn on and off whenever you want and not a good candidate to burn off excess power ("just not using as much naturally-pumped stored power" is not an "excess" of power by definition).
If you have a predictable pricing regime can you vary the power load on a diurnal cycle? Say, drawing more at noon and less at 7pm each day? If so it could still be useful to shape the demand curve (ie use power when solar is cheapest so that meeting the evening peak doesn’t require as much overprovisioning) even though this doesn’t help with inter-day variability of supply.
The problem I’ve always seen with this sort of plan is that the refinery is extremely expensive and so you don’t want it idle; it’s cheaper to overbuild solar than to turn off your refinery for 25% of the day. But interested if this applies here, maybe the energy-intensive bits can be made cheaply?
How large is the tolerance though? Would it be feasible to heat things up a little more from say 9:00 - 17:00 and using more electricity so that you don't need to heat (as much) during peak demand-supply imbalance? Even a couple of hours can help with the duck curve.
They only are if they're incentivized: most ignore the rewards, those you admire who don't ignore self-motivated open-minded-ness and curious-ness, they must have already been rewarded previously for having these traits, and so they continue to express them.
First was operational since 2019. If you push past the “virtual battery” marketing nonsense, a summary of the tech is… they modulate the cooling fans for closed loop thermal regulation, regardless of processing rate (+/- 20% long, 30% short term).
This is particularly interesting to me because we currently have some unanswered questions about how viable renewable energy is for ~100% of generation.
As we get to higher total renewable contribution, presumably we’d see a more dramatic price difference in energy at different time of day.
This tech suggests to me that, as you say, there is low-hanging fruit that could be harvested, and which perhaps isn’t cost-effective yet with a small diurnal energy cost-delta, but with a higher peak-to-trough cost difference might become viable to extract.
It’s worth noting here that seasonal variations seem harder to deal with, and varying the energy intensity of industrial processes doesn’t seem helpful for that issue due to capex/utilization concerns.
And for diurnal fluctuations, batteries are actually not too expensive these days.
> The “virtual battery” concept relies on installing adjustable heat exchangers that can maintain the energy balance in each electrolysis cell irrespective of shifting power inputs. Since aluminium production requires a constant energy supply, any fluctuation could have heavy consequences for the molten metal. The technology also ensures that grid power fluctuations do not affect the magnetic fields in the electrolysis cells.
This seems to be solving the even-harder problem of handling on-demand/dynamic fluctuations rather than planning for a diurnal cycle. I wonder if there is scope to use a heat reservoir (molten salt or similar) as a buffer for these sorts of process; basically if you need to dump heat into a process perhaps you can shift the heat production but leave the process itself unchanged.
Amusingly I was reading the wrong Wikipedia last night and it’s mentioned right there too:
> Particularly in Australia these smelters are used to control electrical network demand, and as a result power is supplied to the smelter at a very low price. However power must not be interrupted for more than 4–5 hours, since the pots have to be repaired at significant cost if the liquid metal solidifies.
No, absolutely not. Aluminum refining, like all industrial processes at scale, takes a long time to get going and needs to run (hence be fed electricity) continuously, not just whenever the wind feels like blowing.
While it is an excellent business opportunity for electricity that is cheap because it is renewable- and why Canada produces more refined aluminum than any other Western country thanks to its electric generation being overwhelmingly renewable for the entire time it's even had a grid- it's not something you can turn on and off whenever you want and not a good candidate to burn off excess power ("just not using as much naturally-pumped stored power" is not an "excess" of power by definition).