I would posit that they hope Wright's Law will take hold; the components can be optimised and the deployment standardised. Also it looks as if most of the stuff can be made within the US or EU, dodging tariffs.
Transmission in this sense does not include distribution losses (by the DNOs, at lower voltages). 8% in your link.
The UK government is now touting datacentre sites with better access to the national grid (transmission network) to avoid the issues inherent in the distribution networks. E.g. Culham which had a grid connection to power the JET fusion experiments.
> There should be more incentive to build data centers in the north
There are clustering advantages for data centres. Lower inter-cluster latency being key. I do not think the UK market is large enough for two hubs, really.
The big question is how much it will cost. For comparison I believe there is a heat battery in Germany using (atmospheric pressure) liquid water (98 C), 50M EUR for perhaps 20x the thermal storage capacity (versus 20 C water).
The use of sand, presumably heated to a much higher temperature than the boiling point of water, seems overkill for district heating (unless peak heat demand requires flow temperatures above 100 C). But it does reduce the volume of sand required, so the size of the storage system.
The cost is a function of the size and mass. So, more heat capacity and less mass means lower cost per mwh.
These things are extremely simple and fairly efficient. It's resistive heating (wires and spools) of a thermal mass (sand/stone) in some kind of container (a simple silo) with a lot of insulation and some pipes to heat up water. Higher temperatures mean getting the heat out is easier and that the battery will work for longer. Basically until the temperature drops below the required temperature.
> So, more heat capacity and less mass means lower cost per mwh.
Can you compare different technologies with these scaling laws? Also what are the limits of these approximations (e.g. taking temperatures to extremes tends to run into maintenance problems).
In this case the sand battery delivers 400 C steam from 600 C sand [0], via some heat exchange fluid (solar salt?) that flows next to the sand. Going through heating/cooling cycles can cause material issues, especially for larger temperature differences.
> I guess more people would prefer to pay a $10 or $20 monthly fee just in case.
The grid becomes an insurance policy. In that case it is justified to ask for the insured party to pay their share of the system costs; both an energy fee and transmission/distribution/generation capacity fee.
> Homeowners having the ability to produce their own energy means they get to opt out of capitalist markets and socialist sharing systems.
All well and good, provided the homeowner opts out of the system. Part of the problem comes when the grid connection is not severed. Using it as a backup option (at the same time as other people, for when the weather is bad) or demanding the grid takes their excess production are counter-productive to the system as a whole.
Also the speed of light might be a bit slow.