Tesla battery researcher unveils new cell that could last 1M miles

It's unfortunate they call it grid storage. Apparently you can make money by connecting a battery to the grid as the one in South Australia does make money, but I have no idea how it does it. Perhaps the price goes through the roof when a coal generator trips out and a battery can react so fast it gets first dibs on the money. The one in South Australia has certainly done that. It must be something like that as the storage is so small and the batteries so expensive they would have to get an astronomical price on what they do sell.

A house battery on the other hand - that's a different matter. The price of retail electricity at is 3 times the wholesale price, and unlike the grid battery the house usually pays nothing to charge it - it comes from the root top solar. Even so batteries aren't competitive yet, as in the return you get on installing one in a house in Australia is currently negative. But if the price drops by 1/2 it will save money by adding a battery.

I struggle to see how grid batteries fit in, but house batteries (which are really a grid battery installed at the other end of the wire) seem like they are just around the corner.

It is called the ancillary market. Basically if the grid voltage or frequency drifts off target too much, the mismatch causes semi-catastrophic shutdown of connected generation. It's... Kind of like if the timing belt in your car broke? Multi-ton generators rotating at thousands of RPM suddenly start to change direction, and they would fly apart if not for safety shutdowns.

The ancillary market exists to prevent that. Standing contracts are posted to bring fast generation like hydro power or gas turbines on the second power gets too low or too high. In Southern Australia there is very little of those resources and due to technical neglect and the governments pro-coal policies, the growth in power demand led to an unstable grid. Their limited number of fast "peaker" plants just couldn't keep up. That's why the battery made money hand over fist- 1.5 years to pay for itself, a wholly unheard of thing in civil projects like this.

Note that I've elided over a lot and ancillary markets worldwide are very highly regulated. They are very complicated, require sub-second reactions, and are generally a problem of the commons. One of the major problems that lead to the SA blackouts was the government expanding the acceptable frequency window- to ~5x what the rest of the world does (iirc). Companies immediately stopped making an effort to switch quickly and made poor long term decisions, relying on undercutting competition.

> I struggle to see how grid batteries fit in, but house batteries (which are really a grid battery installed at the other end of the wire) seem like they are just around the corner.

I think nuclear is one of the likely use cases, but it requires huge changes in carbon regulation. Nuclear is also highly capital intensive and benefits just as much as renewables from storage. A carbon tax is required to make the costs make sense though.

However, they are going to have to upgrade it all anyway if we get loads of electric cars.

As for the coolant loop, I wasn't suggesting to have a valve that can open, just a closed loop to the socket and a heat exchanger that then heats the water flowing through the handle of the plug.

You then store the water in an insulated tank and use it as a preheated supply feeding your main water heating system.