How to Build a Useful Battery Consumption Profile From Your Bills

A monthly electricity total is a starting point, but a home battery proposal is more useful when it reflects the hours when electricity is actually used.

Collect recent electricity bills and any interval usage information available from your provider. Note ordinary weekday and weekend routines, seasonal heating or cooling, electric water heating and planned changes such as vehicle charging. The aim is to explain patterns in demand, not to estimate battery size from the size of the house alone.

A household that uses most of its electricity during daylight may have different storage needs from one that uses most electricity after sunset. Look at daily patterns where data is available. Explain any unusual billing period, such as a holiday or a change in occupancy, before treating it as typical.

Ask the installer to model a representative usage profile with assumptions about solar generation, storage losses, usable battery capacity and the electricity tariff. Discuss whether the objective is reducing imports, shifting energy to another time or providing specified backup capability. These are not identical goals.

Ask competing installers to use the same consumption periods and tariff assumptions. Keep a copy of the data used and compare the proposed results with your actual usage after installation. Avoid treating a modelled saving as a guaranteed annual return, especially if household routines are likely to change.

For UK homes, ask the provider for interval data if available and compare the model against the household’s actual tariff.

Energy Saving Trust — Battery storage

Photo: Evnex Ltd / Unsplash. Stock image for context; not a photograph of a project reviewed in this article.