Your solar panels are converting light into electricity. This means that they are generating electricity during the day, when the house is often empty. Most commonly, this electricity is fed back to the grid.

Light, efficient, eco-friendly battery technology is advancing very fast in response to market demand. It is not by any means cheap yet, but prices are falling as the technology improves and battery storage is beginning to offer a genuine option for increasing savings, reducing your dependence on the grid and further reducing your carbon footprint.

Once you are sure that you are a good candidate to benefit from adding battery storage to your solar panels, the key factor in calculating the cost and potential return lies in the size of battery you will need and the amount of surplus electricity you generate.

What is your load profile?

Homes with 2.5kW to 4kW solar panel systems are generating somewhere between 1,700kwh and 3,400kWh per year. Suitability to benefit from adding or including battery storage will depend on what is called your Load Profile. Put simply this is the way in which you consume your electricity. If you are already using all or most of the electricity you generate then battery storage will bring you little value. If, however, you are generating a significant amount of your electricity when you are not in your house to use it then battery storage becomes a better option.

A qualified solar engineer will help you [choose] the size of battery you require to store your excess solar electricity. Installation costs tend to remain similar no matter the size of the battery. The size of the battery will, of course, affect the cost.

Tesla Powerwall 14kW

The new Tesla 14kW Powerwall battery will cost you approximately £6,500 including installation.

Sonnen

The German company Sonnen, offer a modular system starting at 2kW with additional 2kW batteries available up to a total of 16kW. Approximately £3,200 will install the basic 2kW system including inverter and controls which can take you up to the full 16kW. Each 2kW add-on will then cost a further £850.

LG Chem

The LG Chem range includes 3.3kW, 4.2kW and 9.8kW options for which you can expect to pay £2,200, £3,300 and £5,500 respectively. You should add approximately £1,000 to these prices for installation.

Calculating the savings you can expect from adding battery storage is complicated and requires both the expertise of a qualified installer and knowledge of your own particular system and load profile. If you think that battery storage would be a viable option then your next step should be to book a visit from a solar specialist who will be happy to do the calculations with you and advise you on your best options.

Read more: Green Business Watch