The short answer
Would adding a battery improve our garden centre’s energy project?
A battery needs a clear job. It may shift solar electricity to a later operating period or help manage a suitable tariff and demand pattern. Its value depends on the site profile, equipment, losses, costs and operating arrangement. Compare it with solar alone and do not assume it provides backup power.
Start with the problem the battery would solve
If most solar generation can already be used during opening hours, storing it may add less value than the same battery would provide at a site with unused midday generation and later demand. The answer comes from time-based modelling, not the size of the solar array alone.
A battery can also be considered without solar where the tariff and demand pattern create a useful operating case. Set out when it would charge, when it would discharge and the constraints on doing so. The proposal should show the resulting bill change after charging costs and system losses.
Ask about power as well as energy capacity
Battery power, measured in kilowatts (kW), describes the rate at which it can charge or supply electricity. Energy capacity, measured in kilowatt-hours (kWh), describes the energy it can store. Usable capacity, operating limits and losses affect what reaches the site.
A capacity figure on its own does not tell you which loads can be supplied or for how long. Ask for a design that identifies the equipment, operating strategy, usable energy, power limits and expected changes in performance over time.
Treat backup as a separate design requirement
Solar and a battery do not normally keep a property supplied in a power cut unless the installation includes the necessary equipment and configuration. If resilience matters, make it an explicit requirement from the start.
Identify the essential loads, required duration, acceptable interruption and how the system would operate safely. Keeping tills and communications running is a different design task from supporting a kitchen, refrigeration or the whole centre. Do not infer backup capability from the word ‘battery’ in a quote.
Compare the full operating cost and responsibilities
Include installation, controls, maintenance, insurance, losses, expected degradation and any replacement assumptions. Check warranties against the proposed use, and establish who monitors the system, changes its settings and responds to a fault.
Review location, access, fire-safety arrangements and insurer requirements with the relevant specialists. The electrical design and local network requirements also need checking. Adding storage to an existing solar system is a new design decision, not just a spare component to connect.
Keep trading income separate from electricity savings
An operator may propose flexibility or trading services as an additional use. Ask who controls dispatch, which costs and fees apply, who receives revenue and how that use affects availability for the centre. Such income depends on the actual market, technical and contract arrangements.
Do not count the same battery capacity as simultaneously providing incompatible services. Ask for a base electricity case and a separately identified trading scenario, with assumptions and downside cases. No generic income-per-battery figure can establish the return for your site.
Check the detail
Sources & further reading
- Energy Saving Trust: battery storage (opens in a new tab)
General principles of storing electricity, time-of-use tariffs and losses. Domestic prices, sizes and funding are not applied to a garden centre.
- Energy Saving Trust: solar power facts (opens in a new tab)
Explains the need for additional equipment and configuration for power-cut operation.
- National Grid: G99 connection procedures (opens in a new tab)
Generation and storage connection requirements. Confirm the current route with the network operator for the site.
Links and guidance checked 29 October 2026.