In the long run it's likely that large household batteries like this for aiding in load balancing with solar/wind-centric electrical grids will become as ubiquitous as hot water heaters are.
For hot water heaters, it's obvious that the water would arrive cold if it were boiled in a central location, but electricity can be transmit so efficiently that storing excess load will be much more efficient in centralized locations rather than at individual houses.
My guess is that this will be roughly as common as household generators, since both this and a generator are hedges against the electric grid failing more than anything else.
The equivalent water analogy would be everyone having their own household water cistern in case the water system failed, which I also think is vanishingly rare.
8.7kWh is not a great amount, but if the price was right it could make a lot of sense. Two of those units ... now I'm interested!
Regardless of the time to get ahead: Battery would make a great difference if your goal is to eliminate grid reliance and also to power an EV by solar only.
Whilst in summer a 6.6/5 system can produce 40kWh in a day, during winter months in Australia there really isn't too much sun - and what we get tends to be patchy. So being able to feed it into the battery would be great for avoiding grid use overall, and not to let bursts of sunshine go to waste.
What is improving - energy density, price, need for rare materials?
For the US, there is little chance that such a centralized backup system would ever be built. The US doesn't really build big infrastructure things like this. They prefer everyone to have their own little version, at higher cost and less efficiency.
My point stands: this won’t catch on in the US.
If you have centralized batteries, then the decisions about (a) how big they are (b) who they cut off if the battery is running out and (c) how the batteries impact the pricing of power are all made at the community level, which has value as a way to optimize the way an entire community draws from the power grid, but it lacks precision in how it helps individual households.
If you have localized batteries then people can choose (a) if they need batteries at all, (b) how many batteries they need and (c) how they want to use the batteries to offset their grid usage (some people might want to rely on batteries mainly for emergencies, others to aggressively charge and discharge based on different price levels throughout the day). It might be less efficient in aggregate but it is much more accurate in terms of delivering the benefits to the people that need them.
re: hot water heaters - it should be noted that hot water and steam delivery systems exist and are quite effective(commonly derived from cogeneration sources) e.g.
This is why I'm also pretty happy about solar, because you sidestep a lot of the NIMBY stuff that comes with building huge solar farms.
It's not at all ideal, though I don't know how inefficient it is (this model means that upgrades can happen gradually as well, instead of being multi-decade projects). But hey, you try building anything in most modern city bureaucracies filled with people who care about their real estate values.
Sure it's only storing 8 hours, but the use cases described here are not bad. Imagine if we had 8 hours of battery storage across the world per household!
Voltage management is also a challenge with large amounts of solar export to the grid.
Solar systems are typically capped in the rate they can export to the grid for this reason.
Having a decent household battery to absorb solar output during the day and provide power at night could be a win-win both for households and power distributors.
For me I pay 20c (AUD) per kWH at night for electricity while selling electricity for 10c per kWH during the day. Using the electricity I generate at night instead potentially saves me 10c/KWH. At the right price I’d love one of these.
I had a lot of power failures living in Canada, always due to the above-ground power delivery. I'm guessing this would also count for large parts of the US and the developing world. In Europe, I would bet on centralized solutions because the underground power lines rarely fail. But anywhere with above-ground power delivery, having a battery per household makes a lot of sense.
Let's assume the existing electrical grid to be a somewhat fixed system that gets augmented from time to time here and there but does not get changed in fundamental parameters like voltage. Then there's a certain grid capacity for transmitting power (watts) from central nodes (existing or former big power stations) to that large number of end nodes (homes) or in the opposite direction.
Let's also assume that the combined capacity of all the power lines which connect the homes to the grid massively exceeds the capacity of those (big) lines that connect the "central nodes" to the grid.
This means, that there exists a certain level in the hierarchy of the electrical grid (between central nodes and end nodes) where the lines do indeed match the capacity of all homes.
I'd think, these are the locations where you would build/connect centralized big batteries to the grid.
Because you could then take up all solar power from homes and at the same time you'd have some centralisation which would make building the facilities less expensive because of economy of scale.