Pretty much straight away actually.

In Australia prices were reduced by over $50 a year per person in the state on average once a similar battery went online. Similar policies and market there to this case too. Details: https://en.m.wikipedia.org/wiki/Hornsdale_Power_Reserve

I get that it's easy to be pessimistic but batteries like the above not only pay themselves off in 2years (From the article above, $46million profit in one year alone on a $90million install cost!) they also cut prices on the grid from day one.

Behind the scenes prices can fluctuate between <0 and >100x baseline. These types of installations immediately smooth out the costs. As long as you have competing wholesalers/providers the price reductions will come through pretty quickly based on similar cases.

This project won't do anything (as you likely already know). The reason electricity is so expensive is because it's tied to gas prices, which is an entirely political decision.

I think a big reason for net-zero policies getting bad press, is that these kind of things are difficult to quantify. Energy is largely set by gas price, so having more non-gas assets on the grid probably means you do have cheaper energy (or, at least will have much cheaper energy in the future when gas ceases to dictate the energy price)

I guess what we can't do is step into the alternative world where there's less batteries and renewables, and complain about paying $0.6 per kwh.

I'm paying £0.06 at the moment and I got paid to use electricity on the weekend thanks to the sun shining and wind blowing.

Once there's enough renewables and batteries that the UK is running off of near 100% renewables a decent fraction of the time, so the price is not being set by the gas turbines making up the margin.

If you are paying for electricity in dollars, this battery won't translate to cheaper energy for you. The battery is in Scotland.

Not really. The higher proportion of renewables a country has, the more expensive the energy. See the chart on this page:

https://ca.finance.yahoo.com/news/bjorn-lomborg-solar-wind-p...