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Solar panels don’t always generate the most electricity at the times of day that you want to use it. You can send excess electricity back to the National Grid, and use mains electricity in the evenings and at night, Or, you can install a home storage battery. 13kw Solar Battery
These store up your electricity to use later, making your energy system more independent from the National Grid. Most often, they’re used alongside solar panels, but they may also be useful if you have an energy tariff that offers cheaper electricity at off-peak times.
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This relatively new technology may be worth considering if you generate your own energy at home with solar panels but want to use it outside daylight hours – or plan to start doing so.
It may also be worth considering if you have a time-of-use energy tariff that means you could charge a battery cheaply at off-peak times.
Read on to find out about different energy-storage products, how much they cost, and the pros and cons of batteries.
Or jump straight to our table of the battery storage products and prices .
We asked solar-panel experts and owners for their top tips. Find out how to make the most of your solar panels .
If you have solar PV panels, or are planning to install them, then using home batteries to store electricity you’ve generated will help you to maximise the amount of renewable energy you use. In fact, 60% of people who have, or would consider, a home battery told us the reason was so they could use more of the electricity generated by their solar panels.*
Home-energy storage will also reduce the electricity you use from the grid, and cut your energy bills. If your home is off-grid, it can help to reduce your use of fossil fuel back-up generators.
Even without solar panels, you may be looking to make use of time-of-use tariffs with a battery. These let you store up electricity while it’s cheap (overnight, for example) so you can use it during peak times.
A few energy companies have launched these already, and we expect to see more of them as they can help to balance energy supply and demand, and reduce the need for additional fossil-fuel generation at peak times.
If, for example, it's a windy night and lots of wind turbines are generating electricity for the grid that no-one is using, it makes sense to make the most of that with battery storage.
You used to need a two-rate meter to access these tariffs - new versions can do it with a smart meter instead.
Home-energy storage will cost you upwards of £2,000, so you’ll need to make sure your investment is worthwhile.
If you’re at home during the day and already use a large proportion of the electricity you generate through solar panels, or divert surplus electricity to heat your water (for example), then a battery may not be right for you.
This is because home-energy storage will cost you upwards of £2,000, so you’ll need to make sure it's a worthwhile investment and you'll get your money back on your energy bills. With grid electricity currently very expensive, and projected to stay that way until the end of the decade, the payback times might be quicker than you think.
If you’re looking to save money by installing energy storage, read on for our first impressions of energy-storage systems available now.
The best way to bring down your energy bills is to make sure your home is as energy efficient as possible.
Find out more in our guide to measuring your energy efficiency .
The average home uses between 8kWh and 10kWh of electricity per day. The capacity of new lithium-ion batteries ranges from around 1kWh up to as much as 16kWh.
If you’re using it alongside solar panels, ideally you want a battery that will cover your evening and night-time electricity usage, ready to be charged up again when the sun comes up. Consider how much your solar panels can generate - there's no point buying a battery that's bigger than they can fill.
With a battery that is well chosen for your home's energy use and your solar panels' output, you should find that you can have enough electricity to serve your evening needs for most of the year. You might find that you still draw on grid electricity on the longest winter nights.
We recommend you speak to an expert battery installer for a tailored quote to discuss what will be the right size for your home.
When we surveyed Which? members in 2019 about their solar panels, 106 of our 1,987 survey respondents had battery storage. 25% of them paid less than £3,000 for their battery system, while 41% paid between £4,000 and £7,000 (excluding the cost of the PVs themselves).
Installing a home-energy storage system is a long-term investment to make the most of your solar-generated energy and help cut your energy bills.
Several battery systems come with a 10-year warranty. They require little maintenance, so the main cost is the initial installation. However, solar PV panels can last 25 years or more, so you should factor in the cost of replacing the battery at least once into your total costs.
Batteries are expensive to buy, but prices are dropping all the time, as are solar panel prices . With electricity prices at record highs, the payback times are improving.
Some battery storage companies offer financial benefits – for example, payments or reduced tariffs for providing services to the grid (eg. letting spare electricity from the grid be stored in your battery).
We haven’t yet tested home-energy storage systems to be able to calculate how much they could cost or save you. However you should take into account whether you are on a tariff which has different electricity costs depending on the time of day (time-of-use, or TOU tariff) and, if you generate your own electricity, how much of this you use already.
The Feed-in Tariff (FIT) is now closed for new applications, but many solar panel owners signed up when it was open. If you get it, part of it is based on the amount of electricity you generate and export to the grid. If you don’t have a smart meter the amount of electricity you export is estimated at 50% of what you generate.
If you have a smart meter , your export payments will be based on actual export data. However, if you also have a home battery installed, your export payments will be estimated at 50% of what you generate. This is because your export meter cannot determine whether electricity exported from your battery was originally generated by your panels or taken from the grid.
If you are looking to install solar panels and a solar battery, new Smart Export Guarantee (SEG) tariffs mean that energy firms will pay you for any excess renewable electricity you have generated and export to the grid. All suppliers with more than 150,000 customers have to offer them, but the rates are not very generous.
Compare rates to find the best for you – but check that you’re eligible if you have storage installed.
While battery prices are coming down, it’s still a significant investment.
The best option is to pay for your battery upfront using your own savings. If you don’t have the cash to do this, you could consider a loan. However, remember you’ll have to pay interest on money you borrow, so make sure that gains made from battery storage would outweigh this.
If you live in Scotland, the government has offered interest-free loans to homeowners to fund energy-saving improvements, including energy storage. However, as of 27 June 2023 funding for solar PV and energy storage systems is only available as part of a package with a heat pump or high heat retention storage heaters. You can borrow up to £15,000, which you must repay within 12 years - with the repayment period decreasing depending on the amount you borrow. See Energy Saving Trust’s Home Energy Scotland Grant information to find out more.
Some big tech brands, including Samsung and Tesla, sell home-energy storage systems. Energy companies including EDF Energy, Eon and Ovo are also currently selling solar panel and storage packages.
EDF Energy sells solar batteries and says customers can get a discount in return for helping EDF balance the grid. It says it’s trying to create a ‘network of small-scale batteries to help balance the peaks and troughs of energy production and customer demand'.
Eon Next is selling batteries alongside solar panels so that customers can store excess electricity generated, or charge their electric vehicle. It also pays its customers for excess electricity they export to the grid.
Ovo Energy is selling a home energy-storage device that charges from the grid when electricity is cheaper and less carbon-intensive, and discharges it to run appliances when electricity is pricier and more carbon-intensive later.
The batteries below range from the size of a small computer to the size of a washing machine. Greater capacity means a bigger and heavier battery. Small systems can be wall-mounted, while larger ones sit on the floor. Some companies offer 'stackable' batteries that can be used together.
Use the table to compare prices, capacities and key features.
Bear in mind that usable capacity is usually less than stated capacity. This is because batteries tend to lose some energy in charging and discharging, and most aren’t designed to be fully discharged on a regular basis.
The products in the table above are designed to work with the grid. If you’re off-grid, speak with an installer directly to get an appropriate system for your situation.
Meanwhile the Microgeneration Certification Scheme (MCS) is developing certification for battery storage systems. It says this will ensure consumer protection.
No. You can charge a home battery using electricity you buy from the grid. If you have a time-of-use electricity tariff you could save money by charging your battery when electricity is cheaper, and using the power from it at peak times, to avoid buying from the grid.
But most people do not have time-of-use tariffs yet. These are likely to become more widely available as smart meters are rolled-out, as they make it easy for energy companies to see exactly when you've used energy. Economy 7 and Economy 10 are types of traditional time-of-use tariffs, usually linked to storage heating systems.
There are two types of battery installation: DC and AC systems.
A DC system is connected directly to the generation source (eg. solar panels), before the electricity generation meter. You won’t need another inverter, which is more efficient.
However, charging and discharging is less efficient, so could affect your feed-in tariff , if you have one. DC systems aren't usually recommended if you’re retrofitting a battery to an existing PV system.
DC systems can’t be charged from the grid, according to the Energy Saving Trust.
These are connected after the electricity generation meter. So you’ll need an AC/DC power unit to convert the electricity you generate into AC you can use in your home (and back again to store it in your battery).
AC systems are more expensive than DC systems, according to the Energy Saving Trust. But an AC system won’t affect your FITs payments, as the generation meter can register the total system output.
If you’re installing a storage system, you should notify your local Distribution Network Operator – check with the Energy Networks Association if you’re not sure who it is. You may also need to inform your local council.
Beware of pressure selling by installers. Check our solar panels buying advice for things to look out for, including rapidly reducing quotes and lack of detailed information. A good installer should be able to clearly show you how they’ve worked out what size and type of system you will need for your home, and how they’ve calculated any potential payback times.
*Online survey of 1,567 Which? members who have solar PV and have or would consider a home-battery system, May 2019.
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