Why Funding Matters for Commercial Solar
Installing solar panels on a commercial building typically costs between £700 and £1,100 per kWp, putting a standard 50kWp system in the range of £35,000 to £55,000. That is a significant capital outlay for any business. The good news is that several UK government schemes, tax reliefs, and revenue mechanisms can substantially reduce the net cost and accelerate your payback period, which typically falls between 4 and 8 years for commercial installations.
This guide covers the main funding routes available to UK businesses considering commercial solar in 2026, from tax relief that reduces your upfront cost to export payments that generate ongoing revenue.
Annual Investment Allowance (AIA)
The Annual Investment Allowance lets businesses deduct the full cost of qualifying plant and machinery from taxable profits in the year of purchase, up to £1 million per year. Commercial solar panel systems qualify as plant and machinery, making the AIA one of the most straightforward tax benefits available.
With the main UK corporation tax rate at 25%, a business spending £80,000 on a solar installation can reduce its tax bill by up to £20,000 in the first year. The AIA applies to most businesses regardless of size, and the £1 million annual limit is more than sufficient for the vast majority of commercial solar projects.
For businesses that have already used their AIA allowance on other equipment, full expensing offers an alternative. Introduced in April 2023, full expensing allows companies to deduct 100% of the cost of qualifying new plant and machinery from profits before tax. Unlike the AIA, full expensing has no annual cap, but it is only available to incorporated companies and only applies to new, unused assets.
Energy Technology List
The Energy Technology List (ETL) is a government-maintained register of energy-efficient products across 19 technology categories. While the enhanced capital allowance (ECA) scheme linked to the ETL closed in April 2020, the list remains a valuable procurement tool. It helps businesses identify equipment that ranks in the top 25% for energy efficiency, providing confidence that your solar and associated equipment meets independently verified performance standards.
If you are specifying inverters, battery storage, or energy monitoring systems alongside your solar installation, checking the ETL can help ensure you select equipment that delivers genuine efficiency gains.
Smart Export Guarantee (SEG)
The Smart Export Guarantee requires licensed electricity suppliers to offer a tariff for small-scale low-carbon electricity exported to the grid. For commercial solar installations up to 5MW, the SEG provides an ongoing revenue stream for any electricity your business does not use on site.
SEG tariff rates vary between suppliers, typically ranging from 5 to 15p per kWh. Suppliers set their own rates and contract terms, so it pays to compare offers. The only regulatory requirement is that the tariff must be above zero. At current commercial grid electricity rates of 24 to 34p per kWh, self-consuming your solar generation delivers significantly more value than exporting it, but SEG payments provide a useful return on any surplus.
To be eligible for the SEG, your installation must use an MCS-certified installer and meet the relevant technical standards. This certification requirement applies to systems up to 50kW.
Maximising SEG value
- Compare tariffs across multiple SEG licensees before committing
- Consider whether a fixed or variable rate suits your export pattern
- Review contract lengths carefully, as some suppliers offer higher rates on longer terms
- Factor in battery storage to shift exports to higher-value periods where tariff structures allow
Business Rates Relief
Commercial solar installations can affect your business rates, but the impact is often more favourable than businesses expect. Rooftop solar panels on commercial premises are assessed as part of the property for rating purposes. In many cases, the rateable value increase is modest relative to the energy savings delivered.
Some local authorities offer discretionary rate relief for businesses that install renewable energy. The availability and terms vary by council, so it is worth checking with your local authority before installation. For properties in enterprise zones or qualifying areas, additional relief may apply.
Public Sector and Grant Funding
Public sector organisations in England have access to the Public Sector Decarbonisation Scheme, which provides grants for heat decarbonisation and energy efficiency measures, including solar PV. The scheme is managed by Salix Finance and has distributed over £2.5 billion across multiple phases since 2020. Eligible bodies include schools, hospitals, local authorities, and other public sector organisations.
The scheme aims to reduce public sector building emissions by 75% by 2037 compared to 2017 levels. While the current phase has closed to new applications, further funding rounds are expected. Public sector organisations should monitor announcements from the Department for Energy Security and Net Zero.
Devolved nation schemes
Businesses in Wales and Scotland may have access to additional support. The Welsh Government has operated grant schemes offering up to £10,000 for businesses investing in renewable energy and energy efficiency improvements. In Scotland, interest-free loan schemes have been available to SMEs for renewable energy installations. These schemes have specific eligibility criteria and application windows, so check the relevant devolved government websites for current availability.
Building Your Funding Case
The strongest commercial solar business cases combine multiple incentives. A typical approach would be:
- Reduce the net capital cost using AIA or full expensing to claim 100% tax relief in year one
- Maximise self-consumption to offset grid electricity at 24 to 34p per kWh, which delivers the fastest payback
- Register for the SEG to earn 5 to 15p per kWh on any exported surplus
- Check local incentives including business rates relief and any regional grant schemes
For a typical 50kWp commercial system generating approximately 850 to 1,000 kWh per kWp annually, the combination of tax relief, avoided electricity costs, and export revenue can deliver a payback period of 4 to 8 years, with the system continuing to generate returns across its 25 to 30 year lifespan.
Next Steps
Before committing to a commercial solar installation, get detailed quotes from qualified commercial solar installers who can assess your roof, model your generation potential, and calculate your specific payback based on your electricity usage profile. For systems up to 50kW, choose an MCS-certified installer to ensure eligibility for the Smart Export Guarantee; for larger commercial systems MCS certification is not required. A good installer will help you understand which funding routes apply to your situation and factor them into your financial projections.
The British Energy Security Strategy underlines the government's long-term commitment to expanding solar capacity across the UK, which means the policy environment for commercial solar remains supportive. Acting while current tax reliefs and incentive schemes are in place ensures your business captures the full financial benefit.
