The Tesla battery stores enough energy to run the South Australian grid for 5 minutes and cost 40 million. It's only use is to keep the frequency of the grid fr

The Tesla battery stores enough energy to run the South Australian grid for 5 minutes and cost 40 million. It's only use is to keep the frequency of the grid from drifting. This being my day job, it would add $8k to the electricity bill of the two child household in Australia if we used your solution to store the wind and solar power.