How much do solar batteries cost?
On average, solar batteries cost around £4,500 and typically last 10 to 15 years. They allow you to store energy generated by solar panels that would otherwise be sent back to the grid. This can save money on electricity bills as you pay more per kWh for the energy you take from the grid than you export back through the Smart Export Guarantee (SEG).
Like solar panels, the efficiency of solar batteries does decrease over time, so typically they will need to be replaced at least once within the lifetime of solar panels. This can mean it takes longer to break-even on the cost of installing them. But the technology and efficiency of these renewable energy products are improving all the time.
How do solar panels work?
When the sun shines on a solar panel, photovoltaic (PV) cells absorb energy from sunlight and turn it into DC electricity.
The current flows into an inverter which converts it into AC electricity (AC electricity is used by most appliances).
This electricity is used to power electrical appliances and devices.
Any extra electricity produced by the solar panels can be fed back to the National Grid or stored in batteries for use later.
Solar panels only produce electricity when sunlight is present.
Why use battery storage with solar panels?
Adding battery storage to work in conjunction with a solar panel system allows you to use more of the renewable electricity generated and reduce reliance on the grid. For example, you could store electricity generated via your solar panels during the day to then use at night. Or to contribute when the electrical demand is at such a high level that the Solar PV generation on its own cannot cover it, again reducing reliance on the grid.
Batteries can also be used to store cheap-rate energy between certain hours of the day and then be used to provide power during the day when tariffs and rates could be higher. This is called arbitrage.
Can batteries power a home during a blackout?
As tempting as it is to think that installing batteries means you can live entirely independently ‘off grid’, in reality, most homes are unlikely to have enough battery-stored power to power everything in a house over a long period.
An installer can design a system that prevents batteries from exporting energy back to the grid in the event of a power outage. This is known as anti-islanding protection. This could then be used to power small circuits with a small or low level of electrical power, for example, circuits supplying refrigeration, lighting, communications and entertainment. In the event of a grid power outage, inverters with a form of backup supply are not always powerful enough to start and run large appliances. So this is something to consider if you want to be able to rely on an independent power system.
Do solar panels work on cloudy days?
Yes. Solar panels do work on cloudy days, but they won’t generate as much energy as they do when they get direct sunlight.
Solar panels absorb energy from the sun’s light and can use different wavelengths that pass through thick clouds. Solar panels are most effective when the sun is shining directly on them, but even reflected or partially-obstructed light will work to generate energy. When light hits the solar panels it activates the electrons in the photovoltaic cells, so they move around to create an electrical current.
Are solar panel batteries 0% VAT rated?
From 1st February 2024, the UK Government is extending the VAT relief policy to cover standalone and retrofitted battery storage systems. This means that installers will continue to pay 20% VAT on goods purchased from wholesalers. But end consumers will benefit from 0% VAT on these battery systems.
Previously the 0% VAT rate only applied when batteries were installed as part of a solar power system.
Form 1st February the 0% VAT rate will also apply to batteries retrofitted to existing solar PV systems and standalone battery storage.
Retrofitting batteries to complement existing solar arrays allows business and homeowners to store excess solar energy for use during peak evening hours when solar production drops but energy needs remain high. This is especially attractive for homeowners who are away for much of the daytime.
The change also covers standalone battery storage which allows homeowners and businesses to charge smart batteries overnight when electricity rates are low. The stored energy can then be used during peak rate hours to reduce grid strain, fossil fuel use, and electricity bills.
This policy change should stimulate even more demand for renewable energy technologies, so it offers a great opportunity for electricians and contractors to support the UK's transition to clean energy and a more energy-secure future.