How can solar and a battery cut your business electricity bill?

Solar can reduce imported electricity when generation meets your site's demand. A battery can move surplus energy to later hours, but adds costs and losses. DESNZ reports a non-domestic average of 24.51p/kWh including CCL for the second quarter of 2026 [S1]. Use your avoidable import rate, export terms and interval data to calculate the difference. Checked October 2026.

Last checked 17 October 2026

A small UK business can assess a fully funded solar and battery proposal to explore cutting electricity costs without paying upfront. Test avoided imports against actual demand; battery losses reduce usable energy [S3]. The fully funded model below is illustrative: request written benefit-sharing terms and ongoing costs before treating it as an offer. Start with cutting energy costs.

How does solar self-consumption reduce your bill?

Self-consumption means using your solar photovoltaic (PV) electricity on site. For your calculation, match generation with building and vehicle demand in each interval. Value the imports displaced at the charges actually avoided. Keep fixed charges outside that multiplication: NESO’s network residual structure includes daily fixed amounts [S6]. Before sizing generation, use the business energy saving guide to review your demand.

Start with the business electricity prices hub, which presents DESNZ consumption bands. The official tables distinguish prices including and excluding Climate Change Levy (CCL) [S2]. The opened DESNZ publication confirms an overall average of 24.51p/kWh including CCL for the second quarter of 2026 [S1]. Individual size-band spreadsheet cells could not be read in this check, so the example uses that verified average as a sensitivity input, not as your marginal rate.

Replace it with your site’s avoidable price before making a decision. Read standing charges and CCL with your accountant. Do not add the levy again to a price that already includes it.

What does a battery add, and what can it fail to recover?

A battery stores energy and releases it later; DESNZ notes that designs and efficiencies differ [S3]. Ask for usable kilowatt-hours (kWh), the energy capacity, and kilowatts (kW), the charge and discharge power. Both matter when checking whether stored solar can cover an evening load.

The government’s flexibility roadmap describes shifting demand and storing electricity for other periods [S5]. Your business case should test those functions against actual operating hours. Request a solar-only model before adding storage, so the battery’s extra contribution remains visible.

Peak shaving means limiting your import peak. Ask which bill item or connection constraint that changes. For time-of-use shifting, an assumed 1,000 kWh battery output at a 30p avoided rate is worth £300. At assumed 90% efficiency, input is 1,000 ÷ 0.9 = 1,111.1 kWh. At an assumed 15p charging rate it costs £166.67, leaving £133.33 before wear and other costs. These are assumptions, not market prices. Do not apply this value to energy already counted in a solar-storage calculation.

What could the annual benefit and payback look like?

This is an illustration, not a quote, for a daytime trading building with evening demand. All inputs below are assumptions except the DESNZ reference price [S1]. No charger sales are included, so driver prices and charging sessions are outside this calculation.

The assumed capital budget excludes roof repairs and network upgrades. Annual figures exclude VAT, tax, financing, degradation, replacement and discounting. Obtain those project costs separately before relying on payback.

For mid use, avoided imports are (30,000 + 9,000) × £0.2451 = £9,558.90. Export is 10,000 × £0.05 = £500. Net benefit is £9,558.90 + £500 − £1,000 = £9,058.90. Apply the same formula to the other rows. Each case allocates the entire assumed generation between direct use, battery input and export.

How do fully funded, part funded and self funded compare?

These assumed benefit-sharing terms illustrate the funding choices; they are not available offers. For fully funded, the provider pays, owns and operates, and the host receives 10% of net benefit as an annual payment. Part funded assumes the host pays half the capital for 70% of net benefit. Self funded assumes full host ownership and costs. Define maintenance responsibility, billing and benefit ownership in the actual agreement.

Use unrounded benefit × share for host income. Simple ROI = annual net benefit ÷ host capital × 100; payback = host capital ÷ annual net benefit. Most self funded value is bill reduction, not cash sales.

Test the battery separately: 9,000 × £0.2451 − 10,000 × £0.05 − £300 = £1,405.90 extra yearly value over exporting that solar. An assumed £20,000 battery addition therefore has 7.0% simple ROI and 14.2-year payback, before ageing and replacement. A combined project can conceal a slower storage return.

What limits export income and the final decision?

The Smart Export Guarantee (SEG) covers eligible technologies, including qualifying solar installations up to 5 MW in Great Britain. Payments use export meter readings and contractual rates [S4]. Check metering, certification, storage treatment and permitted export before including income. No export receipt applies to energy used on site.

Review solar costs, battery costs and the commercial solar cost hub. If vehicles share the supply, use solar, battery and charging together and the charging cost tool.

What should you do next?

Take your interval demand, roof details and bill schedule to the site check, then get matched with an installer that covers your area.

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