You are still incurring a cost if you use the electricity instead of selling it back to the grid
Our peak import rate is 3x higher than our solar export rate. In other words, we’d need to sell 3 kWh hours of energy to offset the cost of using 1 kWh at peak.
We’re currently in the process of accepting a quote for home batteries. The rates here highly incentivise maximising self-use.
And this is with no income tax or VAT on sold electricity.