Key facts
Last updated: 30 October 2026- A battery helps when demand falls outside daylight hours or export is limited
- Sized on storage capacity (kWh) and power output (kW) from your usage data
- Most larger Scottish farms have a three-phase supply — the battery must match it
- Standard grid-tied systems shut down in a power cut unless backup is specified
- Batteries are included in your G98 or G99 grid application
- We model your usage before recommending a battery
- Last updated: 30 October 2026
When a battery helps, and when it does not
Solar produces most of its electricity in the middle of the day, but many farm loads fall either side of that peak. Without a battery, surplus solar is exported to the grid at a rate well below what you pay to import. A battery captures that surplus and releases it when you need it, raising the share of solar you use on site. That is the core value, and it only applies if you have demand outside daylight hours to fill.
- Dairy: shifts midday solar into early-morning and evening milking, cooling and washing.
- Arable: smooths dryer and fan loads that run into the evening during harvest.
- Diversified farms: covers evening demand from holiday lets, shops or EV charging.
- Export-limited sites: stores solar that cannot be exported where the local grid is constrained.
If your farm uses most of its power during daylight, solar alone may already cover a large share of demand, and a battery adds less. We model your half-hourly or monthly usage against expected generation before recommending one. If the numbers do not support a battery, we will say so. See our farm battery storage guide for the full picture.
Sizing a battery for a farm
Batteries are sized on two figures: storage capacity in kWh, and power output in kW. Capacity should match the surplus your solar realistically produces on a typical day, not the largest summer peak, because a battery that never fills is wasted money. Power output should be enough to cover the loads you want the battery to run, such as a milk cooling compressor or a grain dryer fan.
Good to know: we model your usage against expected solar generation before recommending a battery. If the numbers do not support one, we will say so.
Your solar system sizing and your battery should be designed together. A battery that is too large for the solar array rarely charges fully, while one that is too small leaves surplus unused. We look at both as a single system.
Three-phase supplies and compatibility
Most larger Scottish farms have a three-phase supply to run motors, pumps and dryers. Battery systems for these sites use three-phase inverters, or are designed carefully around how loads are spread across each phase. The battery, solar inverter and existing distribution board all need to work together, and the combined system is included in your grid application.
If you are adding a battery to an existing solar system, we check whether your current inverter is compatible with battery connection or whether a separate battery inverter is needed. We also review how much surplus you currently export, because that tells us whether a battery is worth fitting at all.
Backup power and grid rules
Standard grid-tied systems switch off during a power cut for safety. If backup matters, for example to keep milk cooling running through a rural outage, the system needs backup-capable inverters and switching, and is usually set to cover selected circuits only rather than the whole farm.
Batteries count towards your total generating capacity, so they are included in your G98 or G99 application to the network operator. Where export is limited, a battery helps you use solar that would otherwise be curtailed, which is one of the strongest cases for adding one.
Next steps
Send us your latest electricity bill and we will model whether a battery adds value for your farm. For more answers, visit Scottish Energy Efficiency for a wider set of energy questions.