An affordable storage system for solar?

A 2.5kWhr Lux hybrid battery storage system from Gener8 will set you back about £3000

Affordable battery storage has been something of a grail for the solar power generator, with the promise it brings to approach truly ‘off grid’ status for residential and similar properties equipped with PV panels. While Tesla’s home storage unit is still an appreciably pricey proposition, solar power expert Gener8 Scotland, based in Fife, is offering a technology that appears to offer similar specs but at a far more affordable price tag, with installations from as little as £2500.

The firm is offering intelligent hybrid battery inverters and energy monitoring systems from Japanese manufacturer Lux Powertek, which can store energy from solar panels, whenever the power generated exceeds that required by the property. According to the firm’s Lee Smith, £3k is about the typical cost at present, and covers purchase and installation of a 2.5kWh storage system. It’s “incredible”, says Smith, who says battery products in this space all rely on the same basic lithium-ion chemistry, and therefore do not vary in efficiency terms.

The batteries

The inverter is fitted with Pylon Tech US2000 Plus batteries, offering about 7,000 cycles per battery – and Smith says this equates to about 15 years of typical usage. The systems are available in power increments of 2.4kWh, and up to eight batteries can be included in one of the Lux Powertek inverter units, providing about 20kWh of storage.

Smith says the system can be retrofitted to “about 99%” of existing solar installations. The battery is only able to draw single-phase power, so three-phase systems are more complicated, although his firm has arranged to undertake this in connection with a wind generator on a customer’s property.

With the Feed-in-Tariff scheme closing at the end of March – the scheme by which renewable energy generation below 5kW has received Government support – many small-scale generators will be worried about a cliff-edge in the cash flow they’ve relied upon from generation, since now you will only be paid for what you export to the grid. Affordable battery systems offer something of a “saviour”, as Lee puts it, since PV systems supported in this way will still allow typical residential customers to get rid of about 90% of their energy bill.

Solar is “the cheapest it will ever be”, believes Smith. A full 4kW system can be installed for around £4599 at the moment – five years ago it was closer to £20k.