At 100 kW with 100 kWh of storage, this is a residential system in name and a commercial system in every engineering respect. Arrays at this scale on a private property bring commercial problems with them — string layout across multiple roof planes, structural loading, and a battery bank that has to be housed, ventilated and protected properly.

The storage is matched one-to-one with the array, which is unusual and deliberate: it allows a very large share of the day’s generation to be shifted into the evening rather than exported. The result is a property that operates largely independently of the grid across a normal day, generating around 13,300 units a month.