Large scale three phase energy generation is always something rotating in sync with the grid. Easiest way to do that is to spin turbine+generator.

All nuclear, coal, biomass power plants just heat water to 300-800°C and push it through turbine.

The thing is that it is really quite robust, and there isn’t any other good solutions to it. They do have quite a lot of loss, but the cooled water after process (still over 100°C) can be used in other industries or district heating improving the efficiency.

Hydropower just spin the turbine with water flow. Wind directly spins the turbine, which is good for efficiency. Solar panels are still quite inefficient, but because they just use space, they make lot of sense even with poorer efficiency.

Being king as having huge losses, but unfortunately it is the best we got

Yes, I totally agree, when talking about these thermal batteries, it should always be made clear.

When Converting heat MWh(t) to electricity MWh(e) is pretty much 2/3 loss in the process, i.e. turbine, and it must be super heated vapor meaning like 800C°.

Edit: But to be clear, they are called heat batteries, even in English.

Yes, and the basic principle of thermal batteries has been quite common here in Finland for some time.

All Finnish cities have district heating networks, so there is some heating plant that generates heat, which is distributed to homes using water as medium. It is closed system where hot water goes in, colder water comes out, which is heated back up. This energy is used to heat the home and heat the cold usage water (faucet/shower etc)

Because the network is lots of water, there is already quite a lot of energy storage in the heat grid itself, so itself works as a battery. In last five years almost all big networks have created water based thermal batteries. Those are 7-8 stories high insulated water containers. These make sense because you just start taking the already heated water from the container to the grid when ever you need.

So the tech itself is quite standard here, just the medium of using sand is new. Sand brings you bit longer storage time, but adds bit of complexity to the process.

Source: I work in a company that owns these kind of networks

He is Russian stooge