Solar battery storage for your home

Solar batteries offer homeowners a significant opportunity to take control of their energy, reduce electricity bills, and enhance energy independence. By storing excess electricity generated by solar panels, these systems ensure you have power even when the sun is not shining, making your home's energy supply more resilient and efficient.

If you are looking to maximise the benefits of your solar panels and battery, Fuse Energy offers competitive export tariffs and smart energy management tools to help you make the most of your self-generated power.

What is a solar battery and how does it work?

A solar battery is essentially an energy storage device that captures surplus electricity produced by your solar panels. Instead of exporting all unused solar power back to the grid for a modest payment, you can store it for later use. This means you can power your home with clean, self-generated electricity during the evenings, at night, or on cloudy days.

The role of solar storage in home energy

Solar storage plays a crucial role in maximising the benefits of a solar photovoltaic (PV) system. Without a battery, any electricity your solar panels generate that is not immediately used by your home is typically sent back to the National Grid. While schemes like the Smart Export Guarantee (SEG) offer payments for this exported energy, storing it for your own consumption can often provide greater financial benefit by reducing the amount of electricity you need to buy from your supplier at higher rates.

How solar batteries integrate with your PV system

A solar battery integrates seamlessly with your existing solar PV system and your home's electrical supply. During daylight hours, solar panels generate electricity. This power first supplies your home's immediate needs. Any excess electricity then flows into the solar battery for storage. When your solar panels are not generating enough power - for example, after sunset or on a particularly gloomy day - the stored energy from the battery is discharged to meet your home's electricity demand. This process is managed by an inverter, which converts the direct current (DC) electricity from your panels and battery into the alternating current (AC) used by household appliances.

The benefits of solar batteries for homeowners

Investing in a solar battery system offers several compelling advantages for homeowners, from financial savings to environmental contributions.

Achieving energy independence and resilience

One of the primary benefits of a solar battery is the increased energy independence it provides. By storing your own electricity, you become less reliant on the National Grid and less exposed to fluctuating energy prices. Some battery systems can also provide backup power during grid outages, keeping essential appliances running when the rest of the neighbourhood goes dark. This resilience offers peace of mind and greater control over your home's energy supply.

Reducing electricity bills and maximising solar PV

Solar batteries significantly reduce your electricity bills by allowing you to use more of the free, clean energy your panels generate. By storing your own power, you can increase your self-consumption rate, directly cutting down on the electricity you need to purchase from the grid. The average UK home uses around 2,500 kilowatt-hours (kWh) of electricity per year1, so reducing grid imports can lead to substantial savings.

Contributing to a greener future

By maximising your use of self-generated renewable energy, you actively reduce your household's carbon footprint. This contributes to a broader effort to decarbonise the energy system and move towards a greener future, aligning with national environmental goals.

Types of solar batteries and key considerations

The UK market offers a variety of solar battery systems, primarily differing in their chemistry, capacity, and overall performance characteristics.

Understanding battery chemistry and capacity

The most common type of solar battery in the UK is lithium-ion, known for its efficiency and relatively long lifespan. Within lithium-ion, Lithium Iron Phosphate (LiFePO4 or LFP) batteries are often highlighted for their safety and durability. Older lead-acid batteries are also available but are generally less efficient and have a shorter lifespan.

Battery capacity, measured in kWh, indicates how much energy a battery can store. It is important to distinguish between a battery's total capacity and its usable capacity, as some energy is reserved to protect the battery and extend its life. For instance, a 10 kWh battery might typically offer 9 kWh of usable capacity.

Power output and efficiency ratings

Power output, measured in kilowatts (kW), determines how much energy the battery can deliver at any given moment. A higher power rating means the battery can run more appliances simultaneously or power larger loads. Batteries typically have both a continuous power rating for normal use and a peak power rating for short bursts, such as when an appliance starts up.

Battery efficiency, often called round-trip efficiency, measures the percentage of energy put into the battery that can be retrieved. Most solar batteries generally offer efficiency ratings between 85% and 95%. Higher efficiency means less energy is lost during the charging and discharging process.

Warranty, lifespan, and safety features

Solar batteries typically have a lifespan of 10 to 12 years, though this can vary with usage and maintenance. Most manufacturers offer a product warranty of around 10 years. These warranties often include guarantees on capacity retention - for example, 70% of original capacity after 10 years - and may specify a maximum number of charge cycles or total energy throughput.

Safety is paramount, and all installations must comply with relevant UK electrical standards.

How to choose the best solar battery for your home

Selecting the right solar battery involves a careful assessment of your household's energy needs, compatibility with your existing setup, and desired smart features.

Assessing your household's energy needs

The first step is to understand your daily electricity consumption and how much solar power your panels generate. This will help determine the appropriate usable capacity (kWh) for your battery. A common mistake is choosing a battery that is either too small, meaning you still rely heavily on the grid, or too large, leading to unnecessary expense. For instance, a smaller home might need a lower kWh battery, while a larger home could require a higher capacity.

Compatibility with existing solar panels and inverters

Ensure any new battery system is compatible with your current solar PV panels and inverter. Some batteries are designed to work with specific inverter types (e.g., AC-coupled or DC-coupled systems). A certified installer can assess your existing setup and recommend compatible options.

Smart energy management features and app integration

Many modern solar batteries come with smart energy management systems and companion apps. These allow you to monitor your energy usage and battery performance in real-time, optimise charging and discharging cycles, and even integrate with time-of-use tariffs to charge the battery when electricity is cheapest. This level of control can significantly enhance the financial benefits and overall convenience of your solar battery system.

Solar battery costs, savings, and payback periods

Understanding the financial aspects is key to deciding if a solar battery is a worthwhile investment for your home.

Upfront investment and installation costs

Solar battery systems typically represent a significant upfront investment, with costs varying based on capacity, brand, and installation complexity. Installing a battery alongside new solar panels can sometimes be more cost-effective than retrofitting one to an existing system, as it avoids duplicate labour costs like scaffolding.

Potential savings and the Smart Export Guarantee (SEG)

The primary savings come from reducing the amount of electricity you buy from the grid. By storing your own solar power, you avoid paying retail electricity prices, which are often significantly higher than what you receive for exporting surplus energy.

The SEG allows homeowners to sell any surplus electricity generated by their solar panels and stored in batteries back to the grid. To qualify for SEG payments, your installation must be Microgeneration Certification Scheme (MCS)-certified, and you need a smart meter capable of providing half-hourly export readings. While SEG rates vary between energy suppliers and must be above zero, storing and using your own power often saves more than exporting it. You can learn more about the SEG to understand how it works.

Calculating your return on investment

Payback periods for solar batteries can vary significantly, depending on factors like your energy usage patterns, the cost of electricity, and the SEG tariff you receive. The return on investment is primarily driven by the "avoided cost" of buying electricity from the grid. Smart tariffs, which offer cheaper off-peak electricity, can further accelerate payback by allowing you to charge your battery from the grid when prices are low and use that stored power during expensive peak hours. Understanding different energy tariffs can help you make the most of your solar battery.

The installation process and what to expect

Once you have decided on a solar battery, the installation process needs to be handled by qualified professionals.

Finding a certified and reputable installer

It is crucial to choose a certified and reputable installer for your solar battery system. Look for installers with MCS accreditation, as this is often a requirement for SEG eligibility and ensures adherence to industry standards. A good installer will have proven experience in solar and battery storage systems and can provide detailed quotes and advice tailored to your home.

Typical installation timeline and requirements

The installation process typically involves an initial site survey to assess your home's energy needs and existing electrical system. The installer will then design a suitable system, ensuring it complies with all relevant building regulations and electrical safety standards. The physical installation usually takes one to two days, depending on complexity. Installations must comply with safety regulations, which typically restrict battery placement in certain areas like lofts or bedrooms, favouring accessible, ventilated locations such as a garage or utility room.

Post-installation maintenance and monitoring

Modern solar batteries require minimal maintenance. However, monitoring their performance through a dedicated app or energy management system is recommended to ensure optimal operation and maximise savings. Your installer should provide guidance on monitoring and any routine checks. It is also important to inform your home insurance provider about the installation, as it represents a material change to your property.

The future of home energy storage and energy independence

Solar batteries are a significant step towards a future where homeowners have greater control over their energy. They empower you to manage your own power supply, reducing reliance on traditional energy models and contributing to a more decentralised, resilient energy system. With ongoing advancements in battery technology and smart energy management, home energy storage will continue to evolve, making energy independence more accessible and efficient for households.

References

1. Ofgem. Review of typical domestic consumption values