Time-of-use tariffs, feed-in credits and VPP payments all change the value of a battery. Here's what to understand.
The feed-in vs buy gap
The fundamental value of a battery comes from the difference between what you're paid for exporting solar (the feed-in tariff) and what you pay to buy power (the usage tariff). The bigger that gap, the more a battery saves you by shifting energy from day to night.
Time-of-use tariffs
Many retailers offer time-of-use pricing — cheap overnight, expensive during the evening peak. A battery lets you charge cheaply (from solar or off-peak) and discharge during the expensive peak, maximising the spread.
Demand charges (business)
For commercial customers, batteries can reduce peak demand charges by discharging during your highest-load periods. This can be where batteries deliver their strongest returns.
Virtual Power Plants (VPPs)
A VPP aggregates many home batteries and sells their combined capacity to the grid during high-demand events. Joining a VPP can pay you credits or a feed-in premium in exchange for letting the network draw on your battery occasionally.
The takeaway
Tariffs change, and the best setup today may differ from next year. A good system lets you adjust charging and discharging strategies as tariffs evolve.