When to Review Your Electricity Plan After Installing a Battery
A home battery changes your household's energy profile significantly enough that the plan you were on before installation may no longer be the best fit. Before the battery, you optimised for import rate and FIT. After the battery, your evening import drops, your export pattern changes, and the battery's charging behaviour interacts with your tariff structure in ways that were not relevant before.
- Review the plan 3 months after battery installation — wait for a full bill showing the new pattern before comparing.
- Evening import typically drops substantially with a battery — plans optimised for high evening import reduction become more relevant.
- The FIT matters less if the battery is storing most surplus solar rather than exporting it.
- Time-of-use plans become more relevant once the battery can be programmed to charge off-peak and discharge during peak — but only if the plan's peak rate is significantly higher than the off-peak rate.
What changes on the bill after a battery
Before battery (solar only):
- Import: household load minus solar self-consumption
- Export: solar surplus beyond household load
After battery:
- Import: household load minus solar self-consumption minus battery discharge (much lower)
- Export: solar surplus beyond household load AND battery state of charge (lower if battery absorbs more)
- Battery charging from grid (overnight, if on time-of-use plan): new import in off-peak window
The battery reduces evening import (its primary job) and may also reduce export (if configured to absorb as much solar as possible before exporting). Both changes affect what the optimal plan looks like.
When time-of-use pricing becomes more valuable
For households without a battery, time-of-use pricing is valuable if they can shift loads (dishwasher, washing machine) into off-peak windows. Most households manage this imperfectly.
For households with a battery, the battery itself can be programmed to:
- Charge from cheap off-peak grid electricity overnight
- Discharge during the expensive peak window in the evening
This is sometimes called "time arbitrage" — buying cheap power and using it when the rate would have been expensive. The value depends on the spread between peak and off-peak rates on the plan.
Example:
- Peak rate: 45c/kWh (5–9pm)
- Off-peak rate: 12c/kWh (midnight–6am)
- Battery capacity: 10kWh usable
- Daily arbitrage value: 10kWh × (45c - 12c) = $3.30/day savings on rate difference
Whether your battery is set up to do this depends on the battery management system and how it is configured. Consult the battery installer if unsure.
The FIT after a battery
With a battery storing most surplus solar, daily export to the grid typically drops. If your previous plan was chosen partly for a strong FIT, that FIT is now earning less because there is less to export.
The new calculation: if export drops from 8kWh/day to 3kWh/day, a 15c FIT plan earns 45c/day in FIT credit instead of $1.20/day. A plan with a 10c FIT but lower import rate may now be cheaper overall.
What to check: read your battery system's generation log for 2–4 weeks to understand the new daily export pattern. Then run the full plan comparison using the reduced export figure.
The VPP (Virtual Power Plant) question
Some battery installers offer the option to enrol in a Virtual Power Plant program. The battery is remotely controlled by the program operator during grid events — typically dispatched to discharge to the grid during high-demand periods — in exchange for bill credits or a payment.
Relevant to plan review because: VPP programs often require a specific retailer plan or have compatibility requirements. If VPP enrolment is planned or has occurred, verify whether the plan meets the program's requirements before switching.
Wait for the first full quarterly bill after battery installation before comparing plans. Check the new daily import and export pattern, assess whether time-of-use pricing benefits the battery's charging schedule, and re-run the full plan comparison on Energy Made Easy using the new numbers.
Analyse your bill to understand your post-battery usage pattern before reviewing plan options.