BrightGridAdding a battery to a solar installation can change how much of your solar electricity is used in the property. However, a battery also increases the installation cost and introduces charging and discharging losses. The right question is not simply whether batteries are useful, but whether the additional value justifies the additional cost.
How solar works without a battery
Solar electricity is first used by the property. If generation exceeds demand, the surplus can potentially be exported. When the sun is not generating enough electricity, the home imports electricity from the grid.
What changes when you add a battery?
A battery can store some of the electricity generated during the day and release it later. This can increase the amount of solar generation that is available during the evening and overnight.
| Scenario | Main advantage | Main consideration |
|---|---|---|
| Solar only | Lower upfront cost | More surplus generation may be exported |
| Solar + battery | More flexibility over when solar is used | Higher upfront cost and storage losses |
| Solar + battery + smart tariff | Can shift grid charging to cheaper periods | Requires suitable tariff and controls |
Where can a battery create value?
- Storing surplus solar
- Reducing evening electricity imports
- Increasing solar self-consumption
- Taking advantage of time-of-use tariffs
- Providing additional energy flexibility
- Potentially providing backup power where specifically designed for it
When might you not need a battery?
A battery may be less compelling where the household already uses a large proportion of its solar electricity during the day, has limited surplus generation or has a relatively low electricity demand.
Battery size matters
Installing the largest battery available is not necessarily the best approach. The battery should be considered against your evening demand, solar generation, tariff and expected cycling.
Compare the incremental return
The important calculation is how much additional financial value the battery creates compared with the additional cost of installing it.
Compare solar with and without a battery
Model the effect of battery storage using your electricity consumption and solar generation.
Compare OptionsFrequently asked questions
Is a solar battery worth it in the UK?
It can be worthwhile where a household has significant surplus solar generation, evening electricity demand or access to tariffs that reward flexible battery operation.
Is solar better with a battery?
A battery provides additional flexibility but also adds cost and energy losses. The best option depends on the household's consumption and tariff.
What size solar battery do I need?
Battery size should be based on solar generation, electricity consumption and the periods when the property uses electricity.
Can a battery charge from the grid?
Some battery systems can charge from the grid when configured and permitted to do so. This can be useful with certain time-of-use tariffs.
Sarah Kimani
Systems Designer at BrightGrid Energy
