Start with when your business uses energy
A battery stores electricity for later use, but storage only creates financial value when the energy it releases is worth more than the cost of charging and operating it. A business with surplus daytime solar and substantial evening demand may have a stronger case than one that already uses almost all its solar generation as it happens.
Use interval meter data, not just your annual electricity bill, to compare solar production with your actual operating hours. This reveals how often a battery could charge and discharge usefully.
Separate the sources of savings
Battery savings can come from several activities. Model each separately so the same stored energy is not counted twice.
- Solar self-consumption: use stored surplus solar instead of buying grid electricity later, allowing for the export income you give up.
- Load shifting: charge during lower-cost periods and discharge during higher-cost periods, after accounting for conversion losses.
- Peak shaving: reduce grid demand during the intervals used to calculate demand charges, where your tariff includes them.
Include the costs that headline payback can miss
The assessment should include the installed cost, usable capacity, charging losses, maintenance, financing and expected capacity degradation. Battery power, measured in kW, also matters: adequate energy capacity in kWh does not guarantee the battery can support a short, high-demand event.
Compare simple payback with a longer-term cash-flow forecast. Check the warranty conditions and whether the model includes equipment replacement or changes to your electricity tariff.
When storage may not be the next investment
A site with little surplus solar, limited evening use or a small difference between charging and discharge electricity prices may see modest returns. Improving solar sizing, shifting flexible loads or reviewing the retail tariff could offer better value first.
Ask for a site-specific battery feasibility assessment with conservative and optimistic scenarios. Backup resilience may have business value too, but it should be considered separately from electricity bill savings rather than used to imply guaranteed payback.