Learn how UK businesses can use batteries with solar to reduce grid imports, increase self-consumption and manage energy costs.
For many UK businesses with solar panels, battery storage can make the solar system more useful and improve control over when electricity is consumed. Solar panels generate electricity during daylight hours, while many businesses also use electricity before the solar system reaches full output, after sunset or during periods when electricity prices are higher. A battery can store surplus solar generation and make that electricity available later.
Whether battery storage is worth the investment depends on the business rather than simply the size of the solar installation.
A warehouse with high daytime electricity consumption may already use most of its solar generation directly and have less need for a large battery. A business that generates substantial solar power during the day but continues operating into the evening may have a stronger case for storage. A site with variable demand, peak-period electricity costs or plans to increase electricity consumption through electric vehicles, machinery or other equipment may also benefit from a carefully designed battery system.
Battery storage should therefore be evaluated as part of the entire commercial energy system. The right question is not simply "Should I buy a battery?" but "How much electricity am I currently exporting, when do I use electricity, what does imported electricity cost, and how much additional value could storage create?"
For UK businesses, this analysis is particularly important because the financial value of storing solar electricity depends on the difference between the cost of imported electricity, the value of exported electricity and the battery's purchase, installation and operating costs. ERS Energy Ltd provides commercial solar and energy storage systems, with storage designed around how much solar generation a business wants to retain and use later.
Commercial battery storage is an energy storage system connected to a business's electrical installation and, commonly, to a solar PV system. During periods when solar generation exceeds the building's immediate electricity demand, the excess electricity can be directed into the battery rather than being immediately exported to the grid. When solar generation falls or the building requires more electricity than the solar panels are producing, stored electricity can be discharged to supply the business.
The result is a shift in when the business uses its own generated electricity. Without storage, surplus generation may be exported. With storage, some of that surplus can be retained and used later.
Ofgem's guidance recognises battery storage as an increasingly relevant technology alongside small-scale renewable generation and provides specific guidance for co-located storage under schemes including the Smart Export Guarantee.
Solar panels and batteries solve different problems. Solar panels generate electricity. Battery storage changes when that electricity can be used. A solar PV system produces electricity according to available sunlight, so generation is generally concentrated during daylight hours. A commercial building, however, may have an electricity demand profile that does not match solar production.
A business may have:
The mismatch between generation and consumption creates an opportunity for storage. The battery gives the business another option — instead of immediately exporting surplus, the system can retain some and use it later, increasing solar self-consumption.
Solar self-consumption is the proportion of electricity generated by the solar PV system that is used by the business rather than exported. For example, if a solar system generates 1,000 kWh over a period and the business uses 700 kWh of that generation directly or through appropriately configured storage, the business has consumed 70% of its generation.
The exact calculation can vary depending on metering, but the principle is straightforward. Higher self-consumption can be valuable because electricity used on site can avoid buying the equivalent amount from the grid.
GOV.UK guidance on the Smart Export Guarantee makes the distinction clear: generators are not paid under SEG for electricity they use themselves, but using their own renewable generation can save money by reducing electricity imported from the grid. This is one of the main reasons a commercial battery can make sense.
A solar PV system does not necessarily produce electricity at exactly the same rate as the building consumes it. During periods of high solar generation, especially around the middle of the day, the panels may produce more electricity than the business needs at that moment. The surplus can be exported to the grid if the system and connection arrangements allow.
The Smart Export Guarantee is a government-backed scheme that requires certain licensed electricity suppliers to offer export tariffs to eligible small-scale low-carbon generators, including solar PV, with installations generally limited to 5MW under the scheme's eligibility rules.
However, the value received for exported electricity is not necessarily equal to the cost of buying electricity from the grid. If the business can store surplus solar and later use it instead of buying electricity, the avoided import cost may be worth more than the export income.
For some businesses, yes. For others, no. The answer depends on the numbers.
The key is to model the actual site. ERS Energy Ltd says its commercial solar systems are sized around the building's roof space and energy use rather than simply maximising the number of panels, and that storage can be included based on how much solar generation the business wants to keep on site.
Before buying a battery, examine the business's electricity demand profile. This is more useful than simply looking at the annual electricity bill. A business could consume 500,000 kWh per year, but the timing of that consumption determines how useful battery storage could be.
The warehouse operates from 7am to 5pm. Most of its electricity demand occurs during daylight hours, and solar generation closely matches its operating schedule.
The business may already consume a high proportion of its solar generation directly. A battery could still provide benefits, but the additional value may be lower.
The manufacturing facility operates from 8am to 10pm. Solar generation peaks around the middle of the day, but production continues for several hours after sunset.
The business exports surplus solar during the afternoon and imports electricity in the evening. A battery could store some of the afternoon surplus and discharge it during evening operations — giving the second business a stronger reason to investigate storage.
This illustrates why battery capacity should not be selected based only on the size of the solar array.
The basic financial benefit of battery storage is the potential reduction in electricity purchased from the grid. Suppose a commercial solar system produces surplus electricity during the afternoon.
If the stored electricity is later used by the business, the company may avoid purchasing that electricity from its supplier. The value of this avoided purchase depends on the tariff.
However, battery efficiency must be considered. Batteries do not return every unit of electricity put into them. Energy is lost during charging, storage and discharge. Therefore, the economic calculation should use realistic round-trip efficiency rather than assuming that every kWh stored becomes one kWh available later.
Round-trip efficiency describes how much energy is available after charging and discharging compared with the amount originally put into the battery. For example, if 100 kWh is sent into a battery and 90 kWh is available for later use, the round-trip efficiency is 90%. The remaining energy is lost through conversion and other system processes.
A battery with higher efficiency can deliver more usable energy from the same solar surplus. But efficiency is only one part of the investment decision. The business should also consider battery capacity, power rating, warranty, expected cycle life, installation costs, inverter efficiency, monitoring, maintenance, replacement risk, financing costs, electricity tariffs and export payments. A battery with excellent technical specifications may still be a poor investment if it is badly sized for the site's demand.
Describes how much energy the battery can store.
Describes how quickly electricity can be supplied or absorbed.
For a commercial business, both matter. A 200 kWh battery with a low power rating may not be capable of meeting a large load instantly, while a battery with high power but little storage may discharge quickly. The correct combination depends on the building's demand profile.
There is no standard battery size for every business. Battery capacity should be based on solar system size, generation profile, consumption, export volume, evening demand, operating hours, tariff structure, desired backup capability, available space, budget and expected cycling.
Oversizing a battery can reduce financial returns. If the business only has a small amount of surplus solar available for storage, a large battery may remain partially empty for much of the year. Undersizing can also reduce potential benefits if significant surplus solar is regularly exported.
The objective is to match the battery to the business. ERS Energy Ltd states that its storage systems are sized according to how much generated electricity the business wants to retain on site.
A commercial battery does not necessarily have to be charged only by solar. Some systems can be configured to charge from the grid when electricity prices are lower and discharge during more expensive periods.
The business case can become more complex because the battery is no longer simply storing free solar generation. The spread between import prices must be large enough to justify battery losses, degradation, network charges, system costs, financing and potential restrictions. The strategy should be modelled before implementation.
For some commercial businesses, yes. A battery can potentially reduce the amount of electricity drawn from the grid during periods of high demand — sometimes referred to as peak shaving.
However, the financial benefit depends on how the business is billed. Commercial electricity contracts can include different tariff structures and charges, so the battery's value cannot be calculated from the unit electricity price alone. A professional energy analysis should review the actual electricity contract and half-hourly consumption data where available.
Battery storage can provide more control over the timing of electricity consumption. This can be valuable as businesses electrify more operations.
If a business adds significant electrical loads, the battery may become part of a broader energy-management system. ERS Energy Ltd lists energy storage, smart-grid connectivity and performance monitoring among its commercial solar capabilities.
Warehouses can be strong candidates for commercial solar because they often have large roof areas. They can also be suitable for battery storage when electricity demand does not perfectly align with solar production. Potential applications include lighting, conveyors, forklift charging, refrigeration, HVAC, automated storage, security systems, office equipment and EV charging. A warehouse with significant daytime demand may already have good solar self-consumption — the battery's role may then be to capture excess production and supply evening or early-morning loads.
Manufacturing facilities can have substantial and complex electricity loads. Machinery may create large demand peaks, while operations can continue beyond daylight hours. Solar can reduce daytime electricity purchases, and battery storage can potentially shift surplus solar into later operating periods and support demand management. Manufacturers should also consider electrical infrastructure — large machinery may require high power levels, and the battery inverter must be designed appropriately.
Offices can also benefit from solar and storage, particularly where the building has large daytime loads, evening operations, EV charging, HVAC demand or server/IT equipment. However, many offices already consume a significant proportion of solar electricity during working hours. In these cases, battery storage may have less additional value than in a business with large midday exports and substantial evening demand. The financial model should determine whether the extra solar utilisation justifies the battery investment.
Retail businesses often have electricity demand throughout opening hours. Lighting, refrigeration, air conditioning, heating, point-of-sale systems and other equipment can create consistent demand. A solar system can offset some of that demand directly. A battery may become more useful when the store remains open after solar production declines or where demand changes significantly during the day. Retailers should consider seasonal demand because solar generation and consumption may both vary throughout the year.
Electric vehicle charging can change a business's electricity profile. A fleet operator may need to charge vehicles during the evening or overnight, while a business with workplace EV charging may have substantial additional daytime loads.
Solar and battery storage can potentially work together: solar feeds business loads, solar surplus charges the battery, and the battery supplies EV charging. This can reduce the amount of electricity required from the grid.
However, the battery should not automatically be sized to cover all EV charging. A load profile should establish how much charging can be supplied directly by solar, how much needs grid electricity and how much storage could realistically contribute.
Some businesses are interested in batteries because they want greater control over their energy supply. A solar-plus-battery system can increase on-site energy use, but it does not necessarily make a commercial property fully independent from the grid.
The amount of energy a business can generate and store depends on solar capacity, weather, roof area, battery capacity, electricity demand, seasonal conditions and operating hours. During periods of low solar generation, the business may still need grid electricity. A battery is therefore better understood as an energy-management tool rather than a guarantee of complete independence.
Some battery systems can provide backup power, but this should not be assumed for every commercial solar installation. Standard grid-connected solar systems may shut down during a grid outage unless the system has appropriate backup capability and controls. Businesses that require continuity during outages should specifically ask for a system designed for backup or resilience.
The design may need backup-capable inverter equipment, appropriate electrical isolation, critical-load circuits, battery capacity, automatic transfer equipment, emergency controls and suitable protection. A business should identify which equipment genuinely needs backup power — keeping an entire industrial facility operational is very different from maintaining servers, security, refrigeration or emergency lighting.
UK businesses considering export payments should understand how battery storage interacts with the Smart Export Guarantee. The SEG is a government-backed scheme for eligible small-scale low-carbon generators. Ofgem states that eligible technologies include solar PV and that the relevant installation capacity limit is generally 5MW, subject to the scheme's eligibility criteria.
Ofgem also provides specific guidance for co-locating electricity storage with installations receiving support under schemes including SEG. This matters because adding a battery can change how electricity flows through the system. Businesses should discuss metering, export arrangements and the treatment of stored electricity with their energy supplier and installer before commissioning the system.
GOV.UK also explains that SEG suppliers determine their tariff terms. The commercial decision should therefore consider both the value of self-consumption and any potential export income.
There is no universal answer. If an electricity supplier offers a strong export rate, exporting surplus may be financially attractive. If the business pays considerably more for imported electricity than it receives for exported electricity, storing solar and using it later may produce greater value.
The battery becomes attractive when the additional value generated through storage is sufficient to justify the investment. The calculation should also include battery degradation.
A battery is not an asset with unlimited cycles. Battery capacity can decline over time due to use, age, temperature and operating conditions. The expected rate of degradation depends on the battery technology, manufacturer, operating profile and environmental conditions.
A simple payback calculation based only on today's electricity prices may overstate the long-term benefit if it ignores capacity degradation, efficiency losses, maintenance, inverter replacement, monitoring, financing, insurance, future electricity prices and export rates. The business case should therefore use realistic assumptions — a battery with a strong first-year saving is not necessarily the best investment if its long-term performance is poorly matched to the site.
Battery lifespan varies by technology, manufacturer, usage and operating conditions. Rather than relying on a single generic number, businesses should review the manufacturer's warranty, guaranteed capacity retention and expected cycle conditions.
Important questions include:
These details can affect the long-term economics of the system.
There is no reliable universal payback period. A battery's return depends on the specific site. The strongest calculations use actual electricity data rather than assumptions.
A business should ideally analyse:
A battery may have a strong business case where it replaces expensive imported electricity regularly. It may have a weaker business case where the business already uses almost all solar generation directly. The correct calculation is therefore site-specific.
ERS Energy Ltd states that its commercial solar systems are designed around actual roof space and energy use and that storage is sized according to how much generated electricity the business wants to keep on site.
Consider a business with solar panels that regularly produces surplus electricity around midday. Without storage, part of that surplus is exported. Later in the day, solar production drops while the business continues consuming electricity, so the business imports electricity from the grid.
Without battery:
Solar surplus → Export • Evening demand → Grid import
With battery:
Solar surplus → Battery • Evening demand → Battery discharge
The potential benefit is the difference between the value of electricity that would otherwise have been exported and the cost of electricity that would otherwise have been imported. The calculation must then subtract battery losses and account for the battery's capital and operating costs. This is why battery economics should be based on actual meter data rather than generic online calculators alone.
Battery storage is not automatically the right investment for every commercial solar installation. There are several situations where a battery may have limited financial value.
A commercial battery deserves serious consideration when the business has several of the following characteristics:
The more closely the battery matches the business's actual energy profile, the stronger the potential business case.
A battery should not be treated as an add-on selected after the solar system has already been designed. The solar array, inverter, battery and building load should be considered together.
ERS Energy Ltd includes energy storage within its commercial solar service and states that storage is sized around the amount of generation the business wants to keep on site. This integrated approach can prevent the battery from being unnecessarily large or too small for the actual site.
Battery storage is installed inside or alongside the building, but the roof still matters because it supports the solar generation that charges the battery. A business planning both solar and storage should therefore assess the roof before installation.
Important considerations include roof age, structural condition, waterproofing, insulation, roof loading, access, existing plant, roof penetrations and remaining service life. If the roof requires replacement, it can be more efficient to complete the roofing work before installing the solar system. ERS Energy Ltd combines commercial roofing and solar services and states that roof condition is checked as part of its solar site visit.
Battery storage should not replace basic energy-efficiency measures. A business should first look at whether it can reduce unnecessary electricity demand. Potential measures include LED lighting, efficient HVAC, heating controls, improved insulation, building management systems, equipment scheduling, efficient motors, improved refrigeration, reduced standby consumption and power factor correction where appropriate.
Reducing demand can make the solar system and battery more effective because less electricity needs to be purchased. Roof insulation can also be important for businesses where heating and cooling demand is significant. ERS Energy Ltd provides commercial roofing and energy-efficiency services, allowing businesses to consider roof condition, insulation, solar generation and energy use together.
A battery should not be installed and ignored. Performance monitoring can show solar generation, battery state of charge, charging cycles, discharge, grid imports, grid exports, system faults and performance trends.
Monitoring allows businesses to compare expected performance with actual results. If the battery is rarely charging, the solar system may not generate enough surplus. If it frequently reaches full capacity early in the day, the system may be undersized. If it reaches minimum state of charge before the business needs it, the system may not have enough usable capacity.
ERS Energy Ltd includes performance monitoring with its commercial solar installations so changes in system output can be identified.
Business owners should ask the installer for clear answers to the following questions.
Export data indicates available surplus.
Helps establish whether there is a genuine use for stored energy.
The avoided cost is a major part of the calculation.
Compare the value of exporting with storing.
Ask how the size was calculated.
Request calculation and assumptions.
Understand the manufacturer warranty and guarantees.
Do not assume these capabilities.
This question can prevent expensive disruption later.
A battery proposal based solely on annual electricity consumption is incomplete. A professional survey should consider the building, solar system, electrical infrastructure and operating profile.
ERS Energy Ltd commercial solar process includes assessment of roof orientation, shading and energy usage before system design. It also states that a roof condition assessment is included during the solar site visit.
The result should be a system designed around the actual business. This is particularly important for larger commercial installations because small errors in system sizing can affect the financial return over many years.
ERS Energy Ltd provides commercial solar PV and energy storage solutions for businesses. Its commercial solar service covers solar PV installation, energy storage systems, BIPV integration, smart-grid connectivity, performance monitoring, electrical installation and grid connection support.
The company states that its solar systems are designed around the building's roof space and energy use, with storage included where appropriate. This integrated approach is useful for businesses that want to understand whether a battery actually makes financial sense rather than simply adding storage because it is available.
ERS Energy Ltd also combines roofing and solar expertise. This matters when a business has an ageing commercial roof and wants to install solar and battery storage as part of a wider energy improvement programme. The roof can be assessed first, with any required roofing work considered before solar installation.
ERS Energy Ltd provides commercial solar services for warehouses, industrial units and other commercial properties, with projects designed around roof capacity and energy use. The company states that it offers energy storage and can include storage within the same commercial solar quotation.
Its service includes site assessment, solar system design, panels, inverters, mounting systems, electrical installation, grid connection support, energy storage where required and performance monitoring.
The business also states that it provides clear, itemised quotations covering panels, storage and any roofing work required. For a business considering battery storage, this creates an opportunity to assess the complete project rather than pricing solar panels and batteries separately.
A business considering battery storage can use the following process.
Collect 12 months of bills and, where possible, half-hourly consumption data.
Establish how much the solar system generates and when.
Determine how much solar is currently exported.
Look at usage after solar production falls.
Compare import cost with export value. Test different capacities and power ratings.
Use realistic round-trip efficiency and model performance over the warranty period.
Specify backup capability separately if needed. Establish whether the roof is suitable for solar.
Compare expected annual benefits with complete installed cost. Consider future prices, growth and EV charging.
This process provides a stronger basis for investment than choosing a battery based on its advertised capacity.
Battery storage can be worth it for a UK business with solar panels, but it should be justified by the business's actual energy profile.
The strongest case usually exists where a commercial solar system produces regular surplus electricity and the business continues to consume significant amounts of electricity after solar production falls. A battery can then increase solar self-consumption, reduce grid electricity imports, shift solar generation into later operating periods, potentially reduce exposure to expensive electricity periods, support energy management, work alongside EV charging and electrification, and potentially provide backup capability when specifically designed for it.
However, battery storage is not automatically profitable. A business that already consumes most of its solar generation directly may receive limited additional value from storage. A battery that is too large for the site's solar surplus may also produce a weaker return than a correctly sized system.
The decision should therefore start with data. Review electricity consumption. Analyse solar generation. Measure exports. Understand the electricity tariff. Identify evening demand. Model battery capacity and power. Include efficiency losses and degradation. Then compare the projected savings with the complete installed cost.
For businesses considering a new solar installation, the battery should be assessed at the same time rather than treated as a later add-on. For businesses with existing solar, a review of actual generation and consumption can determine whether additional storage could improve the system's performance. ERS Energy Ltd provides commercial solar and energy storage solutions designed around a business's roof space and energy use, with storage available as part of its commercial solar service. For businesses considering both solar and roofing work, ERS Energy Ltd can also assess the roof during the solar survey and coordinate work where required.
Get a site-specific assessment covering your solar generation, electricity use, roof condition and whether battery storage could improve your energy strategy.
