With energy bills soaring and people getting tired of relying on fossil fuels, home energy storage is experiencing a growth in popularity in the UK.
These storage systems, most likely in the form of lithium-ion batteries, are also becoming an important component in enabling our transition to cleaner, greener energy.
Understanding the basics, benefits and scenarios of use when it comes to storing energy at home is a key step for homeowners considering this technology. This guide will help you get started on energy storage.
What is home energy storage?
Home energy storage involves using a system to store energy for later use. You can store different types of energy, for example heat, but the most common type of home energy storage system uses a battery to store electricity. This article will concentrate on this type.
The idea with a home battery energy storage system is that you’ll be able to charge it up using either your own electricity generated from solar panels or from cheap energy acquired from the grid. Once stored, you’ll use this lower cost stored energy to power appliances in your home.
The use of home battery storage is growing in the UK and is becoming more commonplace with solar PV panel installation – as it should do in our eyes. You can read more on battery storage market trends here.
Setting it up isn’t too complicated for a professional. Most installers can fit and commission a domestic battery within a day.
How home energy storage works
The main components of a battery energy storage system is the battery itself, an inverter and a control centre. These shouldn’t take up too much space in your home, but you can get an idea of how big battery storage systems are here.
Simply put, the battery will store electrical energy when there’s a surplus and discharge that energy when it’s needed around the home.
It’s most common for a storage battery system to exist with a solar panel array. During the day, and particularly when the sun is shining, solar panels will generate electricity.
Some of that energy can be used immediately around your home, for example to power your fridge freezer or your lights. However, when there’s no or little energy demand from your house, such as when it’s empty in the middle of the day, the electricity being generated from your PV panels can go one of two ways:
- Fed into the national grid
- Directed into your battery storage system for you to use later on
Sometimes it can go both ways, such as when the battery is already fully charged. In terms of a hierarchy of using solar generated energy, it’s most efficient to use it in this way:
- Used to meet energy demand of your home
- Used to charge your battery storage system
- Sent to the national grid (and you’ll receive a payment based on your tariff rates)
This is because it’s a lot cheaper to use your own renewable energy than it is to buy it from the grid. If you have solar panels without a storage battery, it’s likely you’ll be sending energy to the grid at a much lower price than you’ll have to buy it back at.
We go into more detail on storing energy from solar panels here.
Can you store energy without solar panels?
Yes, you can store energy without solar panels. It’s not as effective as using a storage battery with solar PVs, but it can still be done.
Essentially, a battery can store energy from any source. Be it energy generated from solar and wind or coal and gas. Of course, we should be aiming for clean energy generation from renewable sources, but the electrical energy generated in the end is the same.
In homes without solar panels, battery storage systems can be charged by drawing power directly from the grid. This is particularly advantageous when combined with effective variable tariffs which make the price of electricity much cheaper during off-peak hours, such as in the early hours of the morning. This cheap power that’s been stored in your battery, can then be used during busy peak hours when the cost price of electricity is much higher.
Even without solar integration, energy storage systems can still help lower energy bills whilst providing back-up energy in the event of power cuts.
Battery storage without solar panels does have some drawbacks though. There’s a high initial investment, long pay back times, plus your house is still dependent on the grid and exposed to potential price fluctuations.
Best types of battery storage
The most popular type of storage battery at the minute is lithium-ion. These batteries have leapfrogged their predecessor lead-acid battery cousins and haven’t looked back. Lithium-ion technology has taken the market by storm and is set to continue its growth into the future – the lithium-ion battery supply chain is expected to make huge growth of 30% every year from 2022 to 2030.
Li-ion batteries offer better energy density, a longer lifespan, lower maintenance requirements, a higher depth of discharge and the prices are coming down quickly.
The growth of lithium-ion tech has made batteries more accessible to everyday households and businesses looking to make good, energy efficient progress that also makes sense from a cost-effectiveness perspective.
There are plenty of good brands out there with high quality batteries and long-lasting warranties of up to 15 years. Many modern batteries now reach 100% depth of discharge, like the ones available from GivEnergy, Tesla and Huawei. It’s also possible to ‘stack’ modular batteries so you can improve and increase your storage capacity over time. Huawei do a good job of this.
Benefits of home energy storage
Home battery energy storage systems offer several advantages to homeowners.
Financial
One of the most significant benefits is the potential to reduce electricity bills. Even without solar panels, batteries can be used to store energy from the grid during off-peak hours when rates are lower and used during peak hours when rates are higher. This is provided that you have a suitable variable tariff.
When combined with solar panels, battery storage can lead to even greater savings. Some estimates suggest that solar panels plus battery storage can reduce your annual electricity bill by up to 70%. In fact, our calculations show that a battery storage system can save you around £800 a year.
This is because battery storage with solar PV allows you to maximise the use of your own generated energy. Although you can export excess solar energy to the grid, it makes more financial sense to save this energy for your own use. At the same time, you’re also increasing your self-reliance and the overall efficiency of your renewable system. Read more on the benefits of solar battery storage here.
Environmental
In addition to the financial benefits, home battery storage contributes to a cleaner environment by reducing dependence on fossil fuels. If you’re storing your own renewable energy, you know it’s come from a clean, sustainable source – it doesn’t come much better than straight from the sun!
As the world continues its clean energy transition, investing in a home battery storage system can help future-proof your home and prepare you for upcoming developments in the energy sector. Additionally, the presence of green technology like battery storage is increasingly attractive to homebuyers, potentially adding value to your property and increasing its saleability.
Can battery storage power a house?
In theory battery storage could supply enough energy to power a house, but it depends on a few critical factors, such as:
- Battery capacity
- Your energy usage
- The capacity of your solar panels
Whilst most people invest in battery storage to reduce their reliance on the grid and save money on energy bills, it’s essential to have realistic expectations about the system’s capabilities.
A solar battery can provide as much electricity per day as it can store and safely discharge. This is determined by its capacity (measured in kilowatt-hours or kWh), power output and depth of discharge (DoD).
In the UK, the average household uses between 6-10kWh of electricity per day. A well-sized 10kWh residential solar battery can theoretically provide enough electricity for a standard day in a three-bedroom home, powering lights, appliances and even a dishwasher or washing machine. However, energy sapping appliances like electric heating systems or electric vehicle chargers can quickly drain the battery, leaving it unable to power the rest of the house.
Additionally, seasonal weather variations greatly impact the efficiency of solar panels and battery storage. In the summer, a home with solar panels and battery storage may be able to go several days without using grid electricity. But in the winter, solar generation can drop to around a quarter of its summer output, making it less likely for the battery to fully power the home.
How much does home energy storage cost?
The cost of buying and installing a residential battery storage system will vary from manufacturer to installer. However, to give you a general idea, homeowners can expect to pay between £4,500 and £10,000 for a well-sized home battery storage system. The minimum cost for a small battery is around £2,500.
A helpful rule of thumb is to budget approximately £900 per kWh of storage capacity. For instance, a 5kWh system would cost around £4,500, whilst a 10kWh system might be around £9,000.
It’s important to note that installing battery storage separately from solar panels or retrofitting an existing solar setup with batteries tends to be more expensive. To maximise cost-effectiveness, it’s generally recommended to install batteries at the same time as solar panels.
The table below provides a estimate of the expected costs for a lithium-ion battery based on its capacity:
| Battery size (kWh) | Battery price |
| 3-5 | £2,500 – £5,000 |
| 5-7 | £3,500 – £7,500 |
| 7-9 | £5,000 – £10,000 |
| 9-12+ | £8,000 – £13,000+ |
Although lead-acid batteries are cheaper than lithium-ion, we don’t consider them to be a viable long-term solution. They have a short lifespan (< 5 years) and a lower performance compared to lithium-ion batteries.
There’s a marginal amount of financial support available from the government for installing battery storage in the average home. As of February 2024, battery storage will be exempt from VAT, effectively providing a 20% discount on the cost of the system. This exemption applies even without investing in solar panels or other green technology. Aside from that, there aren’t any grants available like there are for installing heat pumps under the Boiler Upgrade Scheme.
Is home energy storage for everyone?
The idea of home energy storage sounds great. But before investing you need to consider factors such as upfront costs, available space and long-term savings.
If your energy consumption is already low or you have limited space for a storage system, a battery may not be the most practical solution.
Additionally, the upfront costs of battery storage systems can be a barrier for some households, with prices ranging from around £4,500 to £10,000. Although long-term savings can be significant, those on a tight budget or facing long payback periods may find it challenging to justify the initial investment.
Practical considerations aside, there are certain scenarios where energy storage is definitely worth considering.
For example, if you have solar panels and your home is usually quieter during the day, a battery would be hugely beneficial. It’s during the day when you’ll be generating most of your energy, and without a battery, almost all of this will be sent to the grid.
Installing a battery at the same time as solar panels is often the most cost-effective and energy-efficient approach, but this may not always be feasible. If an immediate installation isn’t possible, retrofitting solar battery storage at a later date is still an option.
