Is It Better to Export or Store Solar Energy?

As more homeowners across the South East install solar panels and battery storage, a common question quickly follows:

“Is it better to export surplus solar energy to the grid or store it in a battery for later use?”

With rising electricity prices, the Smart Export Guarantee (SEG) and rapidly improving battery storage technology, the answer depends on how your home uses energy – and how you want to maximise return on your solar PV system.

This guide explains how exporting and storing solar energy work, compares the financial and practical benefits of each and helps South East homeowners decide the best approach.

So, Is It Better to Store Solar Energy or Export It?

For most UK homeowners, the best approach is to use solar electricity in the home first, store surplus energy in a compatible battery when it is likely to be needed later, and export any remaining surplus to the grid. However, the most cost-effective option depends on your electricity tariffs, household consumption and battery costs.

Exporting surplus electricity can generate payments through the Smart Export Guarantee (SEG) or another export tariff. Storing that electricity can reduce the amount you need to buy from your supplier later, particularly during expensive evening periods.

A battery is not automatically the most profitable choice for every household. If you use most of your solar electricity during the day, receive an attractive export rate or would need to invest heavily in battery storage, exporting more electricity may make financial sense.

The important question is not simply whether storing or exporting is better. It is how much value your household can get from each unit of surplus solar electricity.

How Solar Export Works (SEG Explained)

When your solar panels generate more electricity than your home is using, excess power can be exported to the National Grid. Under the Smart Export Guarantee (SEG), licensed energy suppliers pay you for every kilowatt hour (kWh) you export.

SEG replaced the Feed-in Tariff and is regulated by Ofgem, ensuring fair access for eligible solar PV systems. To qualify for SEG your system must be MCS certified and installed by an MCS certified installer. You need a smart meter installed with capabilities to read export every 30 minutes and a contract with a SEG licensed supplier.

SEG rates are variable from supplier to supplier, with some requiring you to import electricity from them to access preferential export rates. Most suppliers pay between 3p and 15p per kWh, with rates being significantly lower than imported electricity rates during peak periods.

SEG works best if:

• You are home during the day
• Your electricity use closely matches solar generation
• You want a lower upfront system cost without batteries

How Solar Battery Storage Works

A solar battery stores excess electricity generated by your solar panels instead of exporting it. This stored energy can then be used in the evening, overnight or during periods of high electricity prices.

Benefits of battery storage

• Increases solar self-consumption from ~30-40% to 70-90%
• Reduces reliance on expensive peak time grid electricity
• Works well with time of use tariffs, giving you access to import cheaper electricity for use around the clock
• Offers protection against future price volatility

Battery storage is particularly valuable in the South East, where many households have higher evening demand due to EV charging, heat pumps or home working patterns.

Export vs Storage: A Direct Comparison

Factor	Exporting via SEG	Storing in a Battery
Upfront cost	Lower	Higher
Payment per kWh	Low (SEG rate)	High (avoided import cost)
Energy independence	Low	High
Evening electricity	Grid-powered	Solar-powered
Best for	Daytime users	Evening-heavy households

In simple terms, exporting earns you a small payment, while storing helps you avoid buying expensive electricity during peak hours.

How to Calculate Whether Storing or Exporting Solar Energy Saves More Money

The financial value of storing solar electricity depends on how much you would otherwise earn by exporting it and how much you save by using that electricity later. Your import and export tariffs are both important, particularly if you use a time-of-use (TOU) electricity tariff.

For example, imagine you have 1kWh of surplus solar electricity and the following illustrative tariff rates:

• Electricity import price: 28p per kWh
• Export payment: 12p per kWh
• Battery round-trip efficiency: 90%

If you export the 1kWh, you earn 12p.

If you store that electricity and later use the 0.9kWh available after battery losses, you avoid buying 0.9kWh from the grid. At 28p per kWh, that is a saving of 25.2p.

The difference is 13.2p in favour of storing the electricity, before accounting for battery degradation, installation costs and any other relevant costs.

Actual results will vary according to your import tariff, export tariff, battery efficiency and usage patterns. The figures above are an example, not a forecast of household savings.

When exporting may be the better option

Exporting can be financially attractive if you have a high export rate, relatively low electricity consumption after sunset, limited use for stored electricity or a battery that would be expensive to install.

It can also make sense if you have a time-of-use tariff where the price you pay to import electricity during off-peak periods is lower than the rate you receive for exporting surplus solar energy. In this situation, you could earn more by exporting your solar generation and buying electricity later at the cheaper rate, rather than storing that generation in your battery.

For example, if your export rate is 15p per kWh but your off-peak import rate is 7p per kWh, exporting 1kWh earns 15p, while buying 1kWh later costs just 7p. The difference is 8p in your favour before accounting for battery losses and costs. The comparison should use the actual tariff rates and consider whether the cheaper import period aligns with when you need electricity.

When storing may be the better option

Storing can be more valuable if you regularly export surplus electricity during the day and then buy electricity from the grid in the evening at a significantly higher rate. The benefit depends on how much of that stored electricity you can actually use.

With a TOU tariff, the key is to compare the value of exporting solar electricity against the cost of importing electricity when you would otherwise need it. If peak-time import prices are high, using stored solar energy can deliver greater savings. If off-peak import prices are lower than your export rate, exporting and importing later may be more profitable.

The best strategy may therefore be a combination of storing solar energy, charging the battery from the grid during cheap periods where supported, and exporting surplus electricity when the export rate offers better value.

Can You Combine Battery Storage and SEG?

Yes – and this is often the most effective strategy.

A typical setup prioritises:

• Powering your home directly from solar
• Exporting any remaining excess under SEG, finding a preferential rate of around 15p per kWh
• Charging your battery using off peak tariffs that are usually around 7p per kWh

This hybrid approach maximises savings while still generating SEG income when the battery is full. Some advanced systems can even decide automatically whether to store or export based on electricity prices and usage patterns.

Should You Store Solar Electricity or Charge Your Battery Overnight?

A home battery can do more than store surplus solar electricity. If your battery and inverter support grid charging, and your electricity tariff permits it, you may also be able to charge the battery during cheaper off-peak periods.

This creates three options:

• Store surplus solar: Use electricity generated during the day during the evening or overnight.
• Charge from the grid: Buy electricity when your import rate is lower and use it later when rates are higher.
• Export surplus electricity: Send excess generation to the grid when exporting offers better value than storing it.

The most effective strategy depends on the difference between your import and export rates, battery efficiency, usable capacity and household demand.

For example, if exporting electricity earns more than the effective cost of charging and discharging your battery for later use, exporting may be the better financial decision. Conversely, if storing solar electricity avoids buying expensive peak-rate electricity, keeping that energy for your home may provide greater value.

Some compatible systems and tariffs can automate charging and discharging decisions. Always check the battery’s capabilities, tariff conditions and any export restrictions before assuming that automated optimisation is available.

What Happens to Surplus Solar Energy When Your Battery Is Full?

When your solar panels generate more electricity than your home needs and your battery has reached its charge limit, the remaining surplus can normally be exported to the grid, provided your installation and connection arrangements allow it.

If you want to make more use of that electricity, consider these options:

• Charge an electric vehicle: Schedule charging during sunny periods when your car is at home, using a compatible smart EV charger.
• Heat hot water: A compatible solar diverter can direct surplus electricity to an immersion heater in a suitable hot water cylinder.
• Run appliances during daylight: Shift flexible activities, such as washing or dishwashing, to periods of stronger solar generation.
• Export the remainder: If there is no useful demand and the battery is full, exporting surplus electricity can still generate income under your export tariff.

The best solution depends on your property, equipment and energy habits. You do not need to consume every unit of solar generation at home to benefit from solar panels. Exporting unused electricity remains a useful part of a well-designed system.

What Makes the Most Sense for South East Homes?

In the South East, electricity demand is often highest in the evening – when solar panels are no longer producing. This makes battery storage especially attractive.

Battery systems also:

• Pair well with EV chargers and heat pumps
• Protect against future SEG rate reductions
• Improve long term return on investment as grid prices rise

For most SolarTherm UK customers, battery storage delivers greater overall financial benefit than exporting alone, even when SEG payments are available.

Final Verdict: Export or Store?

• Exporting solar energy is simple and provides modest income
• Storing solar energy maximises savings, control and energy independence
• Combining both usually delivers the strongest long term return

If your goal is to reduce bills, protect against rising electricity prices and get the most from your solar PV system, battery storage is increasingly the smart choice.

Thinking About Adding a Solar Battery?

SolarTherm UK designs and installs tailored solar battery storage systems across Essex, Kent, Suffolk, Hertfordshire and the wider South East and East Anglia, helping homeowners optimise both self-consumption and SEG returns.

Contact SolarTherm UK today to find out whether exporting, storing – or combining both – is right for your home. Get in touch for a free, no obligation quote and design, tailored to your property, usage and future energy needs. No hard sell, just honest, expert advice – and the time you need to make an informed decision.

Your home. Your energy. Your future.

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