Will adding a battery affect your business solar FIT payments?

You can add a battery to business solar receiving Feed-in Tariff payments if eligible generation and export remain measurable. Ofgem's scenario 4.1 shows generation and deemed export continuing with storage after the generation meter [S2]. Other layouts need different checks, especially with grid charging. Agree the evidence with your FIT licensee before installation. Checked October 2026.

Last checked 17 October 2026

Which FIT payments could a battery affect?

Separate generation payments from export payments before asking for a retrofit quote. Ofgem says adding storage need not affect payments if eligible generation and export can still be accurately measured [S1]. A compliant layout is therefore more useful than an assurance that a battery is simply compatible with solar.

Generation is electricity produced by the accredited array. Export is electricity leaving your premises. FIT export can be deemed, using an estimate, or metered [S1]. Find your latest statement and establish which applies. Do not copy the payment assumptions from another site’s installation.

Make the existing scheme record part of the design brief. Include the accreditation reference, meter locations, solar rating and any previous modifications. Ask the designer to mark the accredited equipment clearly on the drawing. For the wider system, read solar panels for business and commercial solar inverters.

Does AC or DC coupling preserve your generation record?

Alternating current (AC) coupling uses a separate battery inverter on the AC side. Direct current (DC) coupling connects storage on the DC side of a shared inverter. The important FIT question is what electricity can pass through the generation meter in the proposed arrangement [S2].

Ofgem’s scenario 4.1 allows generation and deemed export with downstream storage. Scenario 4.4 illustrates a shared-inverter arrangement using an approved net meter [S2]. Neither example approves every product or wiring layout. Ask the installer to identify the matching scenario and any differences in your design.

Request a dated drawing before authorising removal of the old inverter. Have the FIT licensee review the proposed meter evidence. Keep the existing readings and photographs so the installer can document the change at handover.

What changes if you receive metered export payments?

With metered FIT export, the arrangement must distinguish eligible solar export from other sources. Ofgem’s scenario 4.2 shows that downstream storage can preserve generation eligibility while failing the export test when grid-charged electricity is mixed into the export reading [S2].

Ask the designer to trace grid charging, solar charging, discharge to the building and discharge to the network. Record which routes are enabled by settings and whether staff can change them. Submit the complete configuration for review rather than presenting only the physical cable layout.

An alternative is the Smart Export Guarantee (SEG). Ofgem allows FIT generation with SEG export, while excluding duplicate FIT export payments [S5]. Read the business export guide before changing arrangements. This page does not recommend a supplier, tariff or export contract.

Who must you notify before making the change?

Ofgem’s generator guidance requires notification to the FIT licensee when storage is installed. For installations accredited through ROO-FIT, notify Ofgem as well [S3]. ROO-FIT is Ofgem’s accreditation route; check your original paperwork rather than assuming which route applies.

Use this document checklist for the installer and scheme administrator:

• Existing and proposed electrical drawings, with the accredited solar equipment identified.
• Generation and export meter make, model, serial number and evidence of how readings are calculated.
• Inverter and battery operating modes, including grid charging and network export.
• Readings and photographs before any meter is removed, plus the changeover record.
• A written explanation of which generation and export claims remain supported after commissioning.

Keep the response with your scheme records. Ask for outstanding evidence requests to be closed before treating the revised arrangement as ready for payment claims. The checklist is a project record, rather than a substitute for the administrator’s requirements.

Does your existing grid approval cover the battery?

A distribution network operator (DNO) manages the local electricity network. National Grid Electricity Distribution directs storage applications outside its specified smaller-installation arrangements through G99, the technical connection requirements for generation operating alongside the network [S4].

Have the installer check your existing connection agreement, combined inverter capacity and proposed export limit with the relevant DNO. An existing solar approval is not evidence that a changed arrangement has been reviewed. Use the G99 application guide to prepare the records.

Also request a site layout covering battery access, cable routes and the proposed location. Put insurance, maintenance and any backup requirement into the quotation brief. Do not assume that passing the FIT metering review answers those separate design questions.

What could the battery add to your business energy case?

This is an illustration, not a quote, for a workshop with existing solar and metered export. Every numerical input is an assumption. Assume a battery with 60 kWh usable storage and 30 kW discharge power. Kilowatt-hours (kWh) measure stored energy; kilowatts (kW) measure power. Neither rating establishes annual throughput.

Assume installed capital of £10,000, round-trip efficiency of 90%, avoided import at 28p/kWh, foregone export at 6p/kWh and annual incremental maintenance of £200. The design is assumed to preserve generation payments, so existing FIT generation income is excluded from the added benefit. No grid charging is modelled.

Arithmetic: diverted solar × 0.90 × £0.28 gives avoided imports. Subtract diverted solar × £0.06 and £200 to find annual net benefit. Return on investment (ROI) is benefit ÷ £10,000 × 100; payback is £10,000 ÷ benefit. Results are rounded and exclude tax, finance, degradation, replacement and downtime.

For deemed export, do not automatically subtract the same foregone-export figure; confirm the payment basis first [S1]. Replace all assumptions with measured surplus, later demand and your actual contract. Compare the import input with business electricity price data, and check the accounting treatment with your accountant. Existing FIT income must not be presented as new battery revenue.

What should you do next?

Take your scheme documents to the cut energy costs hub and site check. Then get matched with an installer that covers your area, requesting a battery retrofit proposal that preserves auditable generation and export records.

Piggy Pineapple Ltd operates this referral service. We refer enquiries to installer partners and may be paid a fee. Our owner holds shares in at least one partner. Before sharing your details, we name the proposed partner and disclose any shareholding our owner holds in it.