Battery & Grid

For a normal domestic system, no planning permission and no advance approval. The connection is notified to ESB Networks by your installer once the system is commissioned, using an NC6 form. That notification is what allows you to be paid for what you export, so until it is done you are generating but not earning from the surplus.

Sized against evening usage rather than against the panels. A typical Irish home uses somewhere between 5 and 10 kWh between coming home and going to bed, which is the gap a battery is filling. A battery much larger than that spends most of the year part-empty, and one much smaller runs out before bedtime. A year of bills tells us more than the roof does.

Batteries are warranted on cycles and years rather than just time, commonly around 10 years or a stated number of full charge cycles, whichever comes first. Most are also warranted to retain a percentage of their original capacity at the end of that, typically around 70 per cent. Ask which figures apply to the specific battery you are quoted, since they vary more between manufacturers than panels do.

Usually yes, and on some tariffs it is worth doing. If your supplier offers a low night rate, a battery can be set to charge overnight and discharge during the day, which is useful in winter when solar generation is low. Whether it pays depends on the gap between your night and day rates, so it is worth checking your own tariff rather than assuming.