To reduce electricity bills we installed an 8.19kW PV array connected to a 10.24 kWh capacity Energy Storage System (ESS). Between late spring and early autumn this array offsets power used by a 16kW NIBE F2040 to heat an outdoor swimming pool.

The PV array is mounted on a purpose-built pergola which is 75m from the house. This array comprises 26 JA Solar 315Wp bifacial modules connected to an SMA Sunny Tripower 3-phase inverter. With bifacial modules between 3 and 15% of their output comes from diffuse light on the rear of the modules.

An SMA Sunnyboy Storage 6.0 battery inverter and a 10.24 kWh BYD HV battery, comprising 8 x 1.28 kWh battery modules, are located in the basement of the house. The modular construction of the battery provides a flexible solution which allows its capacity to be expanded (up to 34.5 kWh) whilst in service. The PV inverter is AC coupled to the battery inverter. The battery then supplies household loads in the evening when the PV is no longer generating power.

The ESS is connected to the internet and its status and performance can be monitored via an online portal. The ultimate objective is to move towards grid independence and the system is closely monitored to establish whether it will be most cost effective to increase the capacity of the PV array or of the battery.