Battery Storage

You can use batteries in your property to store electricity for use at a later time. Typically, this will be of benefit in 2 scenarios;

i) Storage batteries can capture any surplus power from your renewable energy generation (e.g. solar panels or wind turbine) for use at a later time. ‘Surplus power’ is where your solar array or wind turbine is producing more electricity than your property requires at a given time. Without storage batteries, this electricity would normally be sent to the national grid to be used by other consumers but with storage batteries, this electricity can be stored for use at a time when your solar array or wind turbine is not producing enough electricity to meet the demand in your property. Storage batteries can be installed alongside new solar PV or wind turbine installations or can be retrofitted to existing installations. You can retrofit battery storage to your existing solar PV system without affecting your entitlement to feed-in-tariff payments.

ii) The latest battery technology enables storage batteries to be charged from the grid so if you have ‘Time of Use’ or ‘Off Peak’ electricity tariffs, the battery can be programmed to charge from the grid when electricity is cheap and then discharge to power the appliances in your property when electricity is expensive. The graph below is for a winter’s day in November for a customer with an off-peak tariff who charges his battery between 00:30 hrs and 03:30 hrs when their electricity tariff is very cheap. The solid green block between 00.30 and 03:00 is when the battery is charging from the grid. The irregular green lines later in the day is when the battery is charging from surplus power from the Solar PV system. The stored power is then discharged throughout the day to reduce the amount of expensive electricity needed from the grid. This is shown by the purple lines below when the battery is discharging to power appliances in the property. This feature is particularly useful for Solar PV customers in winter months where the production from the PV array is unlikely to fully charge the batteries. In spring/summer months, many customers choose not to charge from the grid at all as the production from the PV array is ordinarily sufficient to charge the batteries.