Business solar panels: costs, savings, grants and payback explained

Business solar panels allow a company to generate electricity from unused roof or land space, reducing the amount of power it needs to purchase from an energy supplier.

A well-designed commercial solar installation can potentially repay its initial cost within four to eight years. The panels may then continue generating electricity for 25 to 30 years, although the actual return depends heavily on how much solar electricity the business uses itself.

In 2026, a straightforward commercial rooftop installation will commonly cost approximately £700 to £1,200 per kilowatt peak, excluding VAT. Smaller or technically difficult projects can cost more, while very large installations may benefit from economies of scale.

Solar is most attractive for businesses that:

• Use substantial amounts of electricity during daylight hours
• Own their premises or have a long lease
• Have a large, structurally suitable roof
• Expect to remain at the site for several years
• Pay a relatively high electricity unit rate
• Can use most of the electricity as it is generated

It is less attractive when most generation would be exported at a low price, the roof requires major repairs or the local electricity network imposes an expensive connection restriction.

This guide explains commercial solar costs, output, savings, finance, grants, tax allowances, export payments, planning rules and grid-connection requirements.

Prices, tax rules and regulations last reviewed: 29 July 2026.

Business solar panels at a glance

Question	Typical answer
Typical installed cost	£700–£1,200 per kWp for many commercial systems
Small 10kWp installation	Approximately £10,000–£14,000 excluding VAT
100kWp installation	Approximately £70,000–£95,000 excluding VAT
Annual generation	Around 800–1,000kWh per installed kWp
Roof space required	Approximately 4.5–6m² per kWp
Common payback period	Around four to eight years
Expected panel life	Approximately 25–30 years
Typical maintenance budget	Around 1–2% of installation cost annually
Commercial installation VAT	Usually 20%, potentially recoverable
Export payment	Available through SEG for eligible installations in Great Britain
SEG size limit	Up to 5MW for solar PV
Grid application	Usually G99 for commercial installations
Universal UK business grant	No; support is normally local or sector-specific
Planning permission	Often unnecessary for rooftop systems, subject to conditions

These figures are indicative. Roof condition, access, network capacity, system size and electrical work can produce substantial differences between quotations.

What are business solar panels?

Business solar panels are photovoltaic panels installed on commercial premises. They convert daylight into direct-current electricity, which an inverter changes into alternating-current electricity suitable for the building.

The electricity can then be:

1. Used immediately by equipment at the premises
2. Stored in a battery for later use
3. Exported to the electricity network
4. Diverted into processes such as water heating or electric-vehicle charging

The term commercial solar PV distinguishes electricity-generating panels from solar thermal panels, which use solar energy to heat water.

A commercial solar system will normally contain:

• Solar photovoltaic panels
• Roof or ground mounting equipment
• One or more inverters
• Direct-current and alternating-current cabling
• Electrical isolators and protective equipment
• Generation and export metering
• Monitoring equipment
• Grid-protection equipment
• Optional battery storage
• Optional export-limitation controls

Are business solar panels worth it?

Business solar panels can be worthwhile when the value of the electricity generated exceeds the installation, finance, maintenance and replacement costs over the project’s life.

The central consideration is self-consumption.

Electricity used immediately by the business normally replaces electricity that would otherwise have been bought at a commercial import rate. Exported electricity is generally sold for considerably less.

For example:

• Solar electricity used on site might avoid a 24p/kWh import cost.
• The same electricity might earn only 5p/kWh if exported.

In this example, using one solar kWh within the business is worth almost five times as much as exporting it.

The latest official figures are available in the government’s non-domestic electricity price tables. The average UK non-domestic electricity price during the first quarter of 2026 was approximately 24.14p/kWh including Climate Change Levy, but prices vary substantially by business size, contract and consumption profile.

Solar usually provides the strongest financial case for:

• Factories
• Warehouses and distribution centres
• Farms
• Food-production businesses
• Cold-storage facilities
• Supermarkets
• Hotels
• Care homes
• Schools and colleges
• Offices with weekday daytime occupancy
• Businesses charging electric vehicles during the day

Restaurants, pubs and hospitality businesses can also benefit, although their strongest demand may occur after solar generation has fallen. A battery may improve the match in some cases.

How much do business solar panels cost?

The following table provides reasonable 2026 budgeting ranges for straightforward UK rooftop installations.

System size	Approximate panels	Approximate roof space	Annual generation	Indicative cost excluding VAT
10kWp	20–24	45–60m²	8,000–10,000kWh	£10,000–£14,000
30kWp	60–70	135–180m²	24,000–30,000kWh	£27,000–£36,000
50kWp	100–120	225–300m²	40,000–50,000kWh	£40,000–£55,000
100kWp	200–235	450–600m²	80,000–100,000kWh	£70,000–£95,000
250kWp	500–585	1,125–1,500m²	200,000–250,000kWh	£160,000–£225,000

The Department for Energy Security and Net Zero publishes updated solar PV installation cost statistics. These are based principally on installations recorded through the Microgeneration Certification Scheme and should be used alongside quotations for the particular commercial site.

Prices in the table exclude:

• VAT
• Battery storage
• Major roof repairs
• Asbestos removal
• Structural reinforcement
• Exceptional scaffolding or crane access
• Electricity-network reinforcement
• New substations or transformers
• Planning application costs
• Significant switchgear replacement
• Finance interest
• Legal work for leases or PPAs

What affects commercial solar costs?

System size

Larger systems normally cost less per kWp because survey, design, scaffolding, grid and project-management costs are spread across more panels.

A 10kWp installation might exceed £1,200 per kWp, while an uncomplicated system of several hundred kilowatts could fall below £800 per kWp.

Roof type

Installation costs differ between:

• Profiled metal roofs
• Standing-seam metal roofs
• Flat roofs
• Concrete roofs
• Tiled roofs
• Asbestos-cement roofs
• Fragile industrial roofing

A flat roof may require a ballasted or mechanically fixed frame. Ballasted systems avoid some penetrations but place more weight on the structure.

Roof condition

Installing a 25-year solar system on a roof likely to require replacement within five years is usually poor planning.

Where roof refurbishment is approaching, it can be more economical to complete the roofing and solar work as one project.

Structural work

A structural engineer should examine:

• Dead loads
• Wind uplift
• Snow loads
• Fixing points
• Roof deflection
• Corrosion
• Existing damage
• The effect of concentrated ballast

A complete system may add approximately 15–25kg/m², although the actual load can be higher for some ballasted designs.

Site access

Scaffolding, edge protection, fragile-roof platforms, crane hire and restricted working hours can materially increase costs.

Grid connection

The local Distribution Network Operator may require:

• Additional protection equipment
• Export limitation
• Switchgear changes
• Transformer upgrades
• Network reinforcement
• A new connection agreement

These costs should be identified before the business commits to the final system.

Electrical infrastructure

The distance between the roof, inverter and main switchboard affects cable and installation costs. Older switchgear may need replacement before generation can be safely connected.

Panel and inverter specification

Higher-efficiency panels can increase generation from restricted roof space, but may cost more. Inverter design, monitoring, warranties and network compliance also influence the price.

How much electricity do commercial solar panels generate?

Solar output is normally estimated using:

Annual generation = installed capacity in kWp × site yield in kWh/kWp

A typical UK commercial system might generate approximately 800–1,000kWh per installed kWp annually.

A 100kWp system could therefore produce:

100kWp × 900kWh/kWp = 90,000kWh annually

Actual output depends on:

• Location
• Roof orientation
• Roof pitch
• Shading
• Panel temperature
• Inverter efficiency
• Cable losses
• Panel degradation
• Dirt and debris
• System downtime
• Network export restrictions
• Annual weather variation

An installer should provide a site-specific generation model rather than relying on a single national average.

MCS methodology uses location, pitch and orientation data derived from the European Commission’s PVGIS resource. However, any projection remains an estimate rather than a guaranteed level of generation.

What do kW, kWp and kWh mean?

These units are related but measure different things.

Unit	Meaning
kW	The rate at which equipment generates or consumes power
kWp	The rated peak output of a solar array under standard test conditions
kWh	The amount of energy generated or consumed over time
MW	1,000kW
MWh	1,000kWh

A 100kWp array does not generate 100kW continuously. It may approach its rated output during favourable conditions, produce less in cloud or low sun, and generate nothing at night.

How much roof space is required?

Modern commercial panels commonly have individual ratings of approximately 430–550 watts and occupy around two square metres each.

Once spacing, access routes, fire breaks, obstructions and roof edges are considered, businesses should budget approximately:

4.5–6m² of usable roof per installed kWp

A 100kWp system will therefore normally require about 450–600m² of suitable roof.

The usable area can be considerably smaller than the building’s total roof area because of:

• Rooflights
• Air-conditioning equipment
• Smoke vents
• Drainage
• Shading
• Parapets
• Firefighter access
• Weak roof sections
• Required safety distances
• Future maintenance routes

Which roof direction is best?

An unshaded, south-facing roof generally produces the highest annual output per panel.

East- and west-facing systems can still perform well. The Energy Saving Trust estimates that an east- or west-facing installation may generate around 15–20% less than an equivalent south-facing system.

However, an east-west design can be valuable on a business property because it:

• Spreads generation across more of the working day
• Produces power earlier and later
• Can improve self-consumption
• Allows panels to be placed more densely on some flat roofs
• Creates a flatter generation profile

Therefore, a design producing slightly less electricity per panel can sometimes deliver a better commercial return.

North-facing roofs are normally less attractive, although a shallow roof angle and high daytime electricity price can occasionally make part of the space viable.

How should a business size its solar installation?

The largest system that fits on the roof is not automatically the most profitable.

Sizing should begin with at least 12 months of electricity data, ideally in half-hourly intervals. The installer should compare the site’s demand with expected solar generation for every period.

Important questions include:

• What is the site’s daytime base load?
• Does the business operate at weekends?
• Does demand fall during summer?
• Are there seasonal shutdowns?
• Will new machinery increase consumption?
• Are electric vehicles being added?
• Will heating or processes be electrified?
• How much export will the DNO allow?
• How much exported electricity will be worth?

A system is generally most valuable when its generation follows the building’s normal electricity demand.

Oversizing can still make sense where:

• An attractive export agreement is available
• Future electricity demand will increase
• Battery storage is planned
• The marginal installation cost is low
• The business has a credible power-purchase arrangement
• The system supports wider decarbonisation targets

The financial model should nevertheless show the consequences of lower-than-expected consumption.

How do business solar panels save money?

Solar can create value in several ways.

Avoided imported electricity

Every solar kWh consumed behind the meter replaces electricity that would otherwise have been purchased.

The avoidable amount can include:

• The contract unit rate
• Climate Change Levy
• Some consumption-based non-commodity charges
• Certain pass-through charges

It normally does not eliminate:

• Standing charges
• Agreed-capacity charges
• Fixed metering charges
• Finance costs
• Charges unrelated to consumption

The main Climate Change Levy rate from 1 April 2026 is 0.801p/kWh for electricity. A business generating and using 100,000kWh on site could therefore avoid up to £801 of CCL, provided the levy would otherwise have applied to that imported electricity.

Export income

Surplus electricity can potentially be sold through the Smart Export Guarantee or another export agreement.

Peak-demand reduction

Solar may reduce daytime maximum demand where generation coincides with the site’s peak. However, it does not automatically reduce agreed capacity or prevent peaks during cloudy conditions.

Battery storage and active demand management may provide more dependable peak reduction.

Price protection

Owned solar fixes much of the cost of generating electricity upfront. This reduces exposure to future movements in wholesale prices and network charges.

It does not eliminate exposure because the business will still import electricity at night, during winter and whenever demand exceeds generation.

Carbon reduction

Using solar electricity can reduce purchased grid electricity and associated location-based Scope 2 emissions. Carbon reporting should use the current UK government greenhouse-gas conversion factors and explain the accounting method used.

Commercial solar savings formula

A useful first-stage calculation is:

Annual benefit = self-consumed solar × avoided import price + exported solar × export price − annual operating costs

Simple payback is:

Simple payback = net installation cost ÷ annual net benefit

Return on investment can be estimated as:

Annual ROI = annual net benefit ÷ installation cost × 100

For a proper investment decision, use discounted cash flow, net present value and internal rate of return rather than relying only on simple payback.

The model should include:

• Panel degradation
• Inverter replacement
• Maintenance
• Insurance
• Finance interest
• Electricity-price assumptions
• Export-rate changes
• Tax
• Business interruption
• Residual value
• Contract termination costs

Worked 100kWp business solar example

Consider a 100kWp rooftop system with the following assumptions:

Assumption	Figure
Installation cost	£90,000 excluding VAT
Annual generation	90,000kWh
Self-consumption	80%
Electricity used on site	72,000kWh
Electricity exported	18,000kWh
Avoided import price	24p/kWh
Export price	5p/kWh
Maintenance and insurance	£1,500 annually

The annual value would be:

Benefit or cost	Calculation	Annual value
Avoided imported electricity	72,000 × £0.24	£17,280
Export income	18,000 × £0.05	£900
Gross annual benefit		£18,180
Maintenance and insurance		−£1,500
Net annual benefit		£16,680

Simple payback would be:

£90,000 ÷ £16,680 = 5.4 years

The simple annual return before finance, tax and degradation would be:

£16,680 ÷ £90,000 × 100 = 18.5%

This is an illustrative calculation, not a guaranteed return. VAT is excluded on the assumption that the business can recover it. Standing charges and agreed-capacity charges are not treated as savings.

Why self-consumption changes the payback

Using the same 100kWp example, the return changes significantly according to how much electricity is used on site.

Self-consumption	Annual net benefit	Simple payback
50%	£11,550	7.8 years
65%	£14,115	6.4 years
80%	£16,680	5.4 years
95%	£19,245	4.7 years

The calculations assume:

• 90,000kWh annual generation
• 24p/kWh avoided import cost
• 5p/kWh export value
• £1,500 annual operating cost
• £90,000 capital cost

This demonstrates why a credible half-hourly consumption analysis is more useful than a quotation based only on annual consumption.

How long is the payback period?

A commercially attractive system may have a simple payback of four to eight years.

Payback can be shorter where:

• The system is large and inexpensive per kWp
• Daytime self-consumption is very high
• The business pays a high electricity rate
• The roof is simple and accessible
• Tax allowances are used efficiently
• Grid work is minimal
• Maintenance costs are controlled

Payback can exceed 10 years where:

• Most electricity is exported
• The business has low weekend or summer demand
• Extensive roof repairs are required
• Finance is expensive
• Network reinforcement is needed
• Generation estimates are optimistic
• Export rates fall
• The installation is shaded or frequently curtailed

A proposal describing every system as having a three- or four-year payback should be examined carefully.

Business solar finance options

Cash purchase

The business pays for and owns the system.

Advantages include:

• Highest potential long-term return
• Full control over the equipment
• Access to export income
• Potential capital allowances
• No lender or investor restrictions

Disadvantages include:

• Large initial cash requirement
• Business carries maintenance risk
• Capital is unavailable for other purposes

Business loan

The company borrows money and owns the installation.

Compare:

• Interest rate
• Arrangement fees
• Security
• Early-repayment costs
• Repayment profile
• Interest treatment
• Whether repayments are covered by realistic savings

Asset finance or hire purchase

The cost is spread over an agreed period. Ownership may transfer after the final payment.

Tax and accounting treatment depends on the agreement, so it should be reviewed before signing.

Operating lease

A third party owns the equipment and the business makes regular payments for its use. Check who receives export income and who is responsible for insurance, maintenance and inverter replacement.

On-site solar PPA

Under a power purchase agreement, an investor installs and owns the system. The business buys the generated electricity at an agreed rate.

A solar PPA can offer:

• Little or no upfront capital cost
• A rate below imported electricity
• Maintenance handled by the owner
• Long-term price visibility

The disadvantages include:

• Contract terms commonly lasting 15–25 years
• Restrictions on roof repairs or property changes
• Price escalators
• Termination and buyout costs
• Complications when selling or refinancing the property
• Investor control over export income and environmental certificates

Read our full guide to corporate and on-site power purchase agreements.

Roof lease

A third party rents the roof and owns the solar array. The building occupier may receive rent, discounted electricity or both.

The agreement must clearly address access, roof damage, insurance, repairs, removal and what happens if the tenant or owner changes.

Are business solar panels tax deductible?

Solar panels are treated as special-rate plant and machinery for capital-allowance purposes.

Businesses can potentially use the Annual Investment Allowance to deduct the full qualifying cost from taxable profits in the year of purchase. The permanent AIA limit is currently £1 million, although connected businesses and certain partnerships can face restrictions.

HMRC specifically confirms that qualifying solar-panel expenditure can use:

• Annual Investment Allowance
• The 50% special-rate first-year allowance for qualifying companies
• Special-rate writing-down allowances

Solar panels that are not covered by AIA or a first-year allowance enter the special-rate pool, which currently has a 6% writing-down allowance.

HMRC provides a solar-panel example in its capital allowances manual. The general AIA rules are explained in the government’s Annual Investment Allowance guidance.

The timing and value of relief depend on:

• Business structure
• Taxable profits
• Accounting period
• Date of expenditure
• Other capital purchases
• Ownership of the equipment
• Finance arrangement
• Grants received
• Whether the asset is later sold

Capital allowances reduce taxable profit; they do not provide an equivalent cash refund of the installation cost. Obtain tax advice before including relief in the project’s financial return.

Is VAT charged on commercial solar panels?

Most ordinary commercial solar installations are subject to VAT at 20%.

A VAT-registered business may normally recover input VAT where the installation is used for taxable business activities, subject to the usual partial-exemption and business-use rules.

The temporary zero rate for certain energy-saving materials is focused on installations in residential accommodation and qualifying charitable buildings. It does not generally make an ordinary commercial installation VAT-free.

HMRC explains the qualifying buildings in VAT Notice 708/6.

A VAT-registered business should normally compare project costs and returns excluding recoverable VAT. A business unable to recover VAT should include it as a genuine project cost.

Are business solar grants available?

As of July 2026, there is no single UK-wide capital grant that pays for solar panels for every ordinary business.

Available support is generally:

• Local-authority funding
• Regional growth funding
• Sector-specific grants
• Rural business support
• Innovation funding
• Net-zero programmes
• Subsidised energy audits
• Low-interest green finance

Examples available during 2026 have included a grant of up to £3,000 for eligible businesses in Three Rivers and Green Enterprise Grants of £500–£5,000 covering up to 50% of eligible costs in Mid Devon.

These examples illustrate how local the market is. They do not mean equivalent funding is available in every postcode.

Ofgem recommends checking the government business finance finder and local council schemes.

Before applying:

1. Check whether approval is required before ordering.
2. Confirm whether the grant is paid upfront or retrospectively.
3. Review minimum and maximum project values.
4. Check business-size and location requirements.
5. Confirm whether solar PV is eligible.
6. Obtain the required number of quotations.
7. Check completion and claim deadlines.
8. Ask how the grant affects capital allowances.

The Smart Export Guarantee is not a grant. A PPA advertised as “free solar” is also a long-term commercial agreement rather than free equipment.

Business rates and solar panels

In England, eligible plant and machinery used for on-site renewable generation and storage is exempt from business rates until 31 March 2035. This can include rooftop solar panels and associated battery storage.

The exemption is subject to the statutory conditions, including how the generated electricity is used. Scotland, Wales and Northern Ireland operate separate non-domestic rating systems, so businesses should check the position with their local assessor or rating adviser.

Do not assume the whole property’s business-rates bill will disappear. The exemption concerns eligible renewable plant and machinery rather than the underlying premises.

Can businesses sell solar electricity?

Eligible businesses in Great Britain can receive payment for electricity exported through the Smart Export Guarantee.

Ofgem’s rules cover solar PV installations with total installed capacity of up to 5MW. The supplier sets:

• Export rate
• Contract length
• Payment frequency
• Meter requirements
• Certification requirements
• Eligibility conditions

The tariff must pay more than zero, but there is no government-set minimum price above that.

Published business export products in July 2026 ranged from around 3p/kWh for some basic tariffs to approximately 12p/kWh for certain conditional products. Rates can change, and higher offers may require the business to purchase imported electricity, equipment or another service from the same supplier.

A business does not normally have to use the same company for imported electricity and SEG payments.

Read our regularly updated guide to Smart Export Guarantee rates for businesses.

SEG applies in England, Scotland and Wales. Northern Ireland has separate electricity-market and export arrangements.

What is required for an export tariff?

A business will normally need:

• Eligible generation technology
• Suitable installation certification
• A meter capable of recording exported electricity
• Half-hourly export data
• An export MPAN
• DNO connection approval
• A completed supplier application
• Bank and tax details
• Evidence of ownership or the right to receive payments

Larger installations may use a negotiated PPA or other export contract instead of a standard SEG tariff.

Check ownership carefully where panels are funded through a PPA, lease or landlord arrangement. The equipment owner may retain the export income.

Why self-use usually beats exporting

Suppose a business can:

• Avoid buying electricity at 24p/kWh
• Export solar electricity at 5p/kWh

Using 10,000kWh on site saves:

10,000 × £0.24 = £2,400

Exporting the same quantity earns:

10,000 × £0.05 = £500

The difference is £1,900.

Possible ways to increase self-consumption include:

• Running energy-intensive processes during daylight
• Charging electric vehicles during the day
• Pre-cooling refrigerated areas
• Heating water during solar-production periods
• Staggering equipment schedules
• Adding appropriately sized battery storage
• Moving maintenance and cleaning operations into daylight hours

Operational changes must not compromise productivity, food safety or equipment warranties merely to chase a small energy saving.

What are G98 and G99 applications?

Solar panels operating alongside the public electricity network must comply with the relevant network-connection requirements.

G98

G98 normally applies where aggregate generation capacity does not exceed 16 amps per phase.

This is approximately:

• 3.68kW on a single-phase supply
• 11.04kW across a three-phase supply

The simplified G98 process commonly allows installation followed by notification to the DNO.

G99

Generation above 3.68kW per phase normally falls under G99. The installer generally needs to apply to the DNO before connecting or commissioning the system.

Most commercial solar installations therefore require G99 rather than G98.

The DNO can:

• Approve the requested export capacity
• Offer a lower capacity
• Require export limitation
• Specify protection settings
• Request technical studies
• Quote for reinforcement
• Refuse the requested design pending changes

The Energy Networks Association provides a commercial generation connection guide.

G100 export limitation

A G100-compliant export-limitation system can prevent the site from exporting above an agreed level.

For example, a business may install a 250kWp array but be limited to exporting 50kW. Generation above the building’s demand and export limit is curtailed unless it can be stored or used elsewhere.

This can avoid or reduce network reinforcement costs, but it can also reduce generation revenue. The financial model must include expected curtailment.

Does business solar require planning permission?

Many rooftop solar installations on non-domestic premises in England qualify as permitted development, meaning a full planning application may not be required.

Important conditions include:

• Panels on a wall or pitched roof should project no more than 200mm.
• Flat-roof equipment should not extend more than one metre above the roof.
• Roof-mounted equipment should normally remain at least one metre from the external roof edge.
• Visual effects should be minimised where practicable.
• Restrictions apply to listed buildings and scheduled monuments.
• Additional requirements can apply in conservation areas and other designated locations.
• Some projects above 1MW can use permitted-development rights subject to prior approval.

The Planning Portal’s non-domestic solar guidance explains the rules for England.

Planning is devolved. Scotland, Wales and Northern Ireland have their own regulations, and local restrictions can remove permitted-development rights.

A lawful development certificate can provide useful confirmation where planning status is commercially important.

Do building regulations apply?

Building regulations will normally apply to roof-mounted solar work.

The project must address:

• Structural loading
• Fire protection
• Electrical safety
• Weatherproofing
• Roof access
• Wind and snow loading
• Penetrations
• Safe isolation
• Relevant building-control notifications

The Planning Portal confirms that the existing roof’s ability to carry the installation must be checked and demonstrated.

Planning permission, building regulations and DNO approval are separate requirements. Receiving one does not automatically satisfy the others.

Is the roof suitable?

A proper feasibility assessment should examine more than the available area.

Roof age and condition

The roof should have sufficient remaining life to support a 25- to 30-year project. Existing water ingress, corrosion or damaged sheets should be investigated first.

Structural strength

A qualified engineer should review the roof structure and the installer’s proposed loading.

Asbestos

Older commercial buildings may contain asbestos-cement roof sheets or asbestos-containing materials around service areas.

The survey, design and installation must comply with asbestos-management requirements. Panels should not simply be fixed through suspected asbestos material without an appropriate assessment and working method.

Shading

Shading can come from:

• Trees
• Nearby buildings
• Rooflights
• Ventilation equipment
• Chimneys
• Parapets
• Signs
• Communications equipment

Even limited shading can affect an entire string if the system is not designed correctly.

Roof warranty

Check whether the solar installation could invalidate an existing roof guarantee. The roofing manufacturer may require approved mounting components or installers.

Fire and insurance requirements

Discuss the proposal with the property insurer before signing an installation agreement. Insurers may require particular standards for:

• Panel layout
• Fire breaks
• Inverter location
• DC cable routing
• Isolation
• Roof access
• Combustible roof materials
• Inspection and maintenance
• Fire-service access

Should businesses add battery storage?

Battery storage can increase the proportion of solar generation used on site, but it does not automatically improve the project return.

A battery may add value by:

• Storing midday surplus for evening use
• Reducing peak demand
• Avoiding expensive time-of-use periods
• Supporting electric-vehicle charging
• Participating in flexibility services
• Preventing export curtailment
• Providing backup where specifically designed to do so

A battery can weaken the return where:

• There is already high daytime self-consumption
• Import and export prices are similar
• The battery cycles infrequently
• Finance costs are high
• The battery is oversized
• Network or market revenues are overestimated

Battery sizing should use half-hourly or finer data rather than a simple percentage of the solar array.

Standard grid-connected solar and battery systems normally shut down during a power cut to protect network workers. Backup operation requires suitable islanding controls, switchgear and a design capable of supporting the required loads.

Can rented businesses install solar panels?

A tenant will normally need written landlord approval.

The agreement should specify:

• Who owns the equipment
• Who pays for installation
• Who receives export income
• Who receives tax allowances
• Who maintains and insures the system
• Rights of access
• Responsibility for roof damage
• Arrangements for roof repairs
• What happens when the lease ends
• Whether panels must be removed
• Who pays removal costs
• Whether a future tenant can use the system

The remaining lease should be long enough to support the investment. Break clauses and relocation plans can undermine the financial return.

Where the tenant’s lease is short, a landlord-owned system or third-party PPA may be more appropriate than a direct purchase.

Commercial solar by business type

Business type	Why solar may fit	Main issue to check
Warehouse	Large roof and daytime activity	Low electricity demand relative to roof size
Factory	High daytime machinery load	Roof condition and electrical capacity
Farm	Large buildings, refrigeration and machinery	Roof integrity and seasonal consumption
Office	Predictable weekday demand	Low weekend and holiday usage
Retail	Daytime lighting, cooling and refrigeration	Landlord rights and roof access
Hotel	Year-round electrical demand	Evening load and roof complexity
Care home	Continuous consumption	Resilience and safeguarding requirements
School	Large roof and daytime use	Low summer-holiday consumption
Cold storage	High continuous refrigeration demand	Reliability and power quality
Restaurant	Refrigeration and daytime preparation	Stronger evening demand
EV fleet depot	Daytime or managed charging	Connection capacity and charging schedule

How long does installation take?

A typical project can involve the following stages.

1. Data and feasibility review

The installer collects electricity bills, interval data, plans and roof information.

Typical duration: one to three weeks.

2. Site and structural surveys

The roof, electrical system, access, shading and structure are inspected.

Typical duration: one to four weeks.

3. Preliminary design and financial model

The installer proposes capacity, generation, self-consumption, cost and payback.

4. DNO application

A G99 application is submitted. Simple applications may be resolved relatively quickly, while reinforcement or high-voltage work can take several months.

5. Planning and building control

Planning permission, prior approval or confirmation of permitted development is obtained where required.

6. Final design and procurement

Panel layouts, inverter selection, cabling, protection and construction arrangements are finalised.

7. Installation

A straightforward small commercial project may be installed in several days. Larger systems can take several weeks.

8. Testing and commissioning

The installer tests the equipment, completes network documentation and hands over the system.

9. Export registration

An export MPAN, export meter and SEG or PPA arrangement are established where required.

A credible contractor should provide a programme showing dependencies rather than promising one fixed completion date before surveys and DNO approval.

How to compare commercial solar quotations

Ask every contractor to use the same electricity data and financial assumptions.

Compare the following:

Quotation item	What to check
Installed capacity	Total panel capacity in kWp
Panel count	Number, manufacturer, model and wattage
Inverter capacity	AC rating, number, model and replacement strategy
Annual generation	Location, pitch, shading and loss assumptions
Self-consumption	Calculation based on interval data
Electricity value	Import and export rates used
Degradation	Annual decline assumed
Capital cost	Whether VAT and all installation work are included
Network work	DNO application, fees and reinforcement assumptions
Roof work	Surveys, reinforcement and repairs
Access	Scaffolding, edge protection and crane hire
Monitoring	Platform, licence costs and data ownership
Maintenance	Inclusions, response times and annual price
Warranties	Product, performance, inverter and workmanship cover
Insurance	Contractor cover and post-installation requirements
Payback	Whether tax, finance and replacements are included
Export income	Tariff, term and ownership
Exclusions	Anything that could become an additional charge

Do not compare quotations solely by price per kWp. A cheaper proposal can use unrealistic generation, self-consumption or electricity-price assumptions to produce an apparently superior return.

Questions to ask a commercial solar installer

1. Have you installed systems on this roof type?
2. Can you provide references for similar projects?
3. Is the generation forecast site-specific?
4. How was self-consumption calculated?
5. Does the price include the structural survey?
6. Does it include the DNO application?
7. What network costs have been allowed for?
8. Is planning advice included?
9. Who is responsible for building control?
10. What happens if the roof leaks?
11. Which warranties are insurance-backed?
12. What monitoring data will we own?
13. Who receives export payments and REGOs?
14. What maintenance is required?
15. What happens if an inverter fails?
16. Are fire and insurer requirements included?
17. Which assumptions could change the price?
18. What is excluded from the quotation?

Warranties and expected lifespan

Commercial solar panels commonly have:

Component	Common warranty range
Panel product warranty	Approximately 12–25 years
Panel performance warranty	Approximately 25–30 years
String inverter warranty	Approximately 5–15 years
Mounting system warranty	Approximately 10–25 years
Installer workmanship	Approximately 2–10 years
Battery warranty	Commonly based on years, cycles or retained capacity

A performance warranty does not promise that the whole installation will generate a particular number of kWh. It normally guarantees that an individual panel will retain a stated percentage of its original rated output.

Inverters are more likely than panels to require major replacement during a 25-year project. The financial model should include this possibility.

Solar panel maintenance

Commercial solar is relatively low-maintenance, but it is not maintenance-free.

A suitable plan can include:

• Continuous generation monitoring
• Alerts for inverter faults
• Regular visual inspections
• Electrical testing
• Thermal imaging
• Checking mounting and roof condition
• Cable and isolator inspection
• Vegetation control for ground arrays
• Bird-proofing where required
• Cleaning based on actual soiling
• Updating emergency and isolation information
• Inverter servicing
• Export-meter checks

Cleaning should be based on local conditions and measured performance. Frequent cleaning may be unnecessary on a steep, rain-washed roof but important near dust, agriculture, birds, industry or coastal deposits.

Common commercial solar mistakes

• Installing before DNO approval: A large system should not be ordered on the assumption that unrestricted export will be permitted.
• Maximising panel numbers without checking demand: A roof-sized design can create excessive low-value export.
• Ignoring roof life: Removing and reinstalling panels for a roof replacement can create a large unplanned cost.
• Believing an advertised payback without checking assumptions: Small changes in electricity price, self-consumption and generation can move payback by several years.
• Treating SEG as a grant: SEG pays for eligible exported units; it does not fund installation.
• Assuming solar works during power cuts: Ordinary grid-tied installations shut down unless backup operation has been specifically designed.
• Overlooking landlord or lender consent: Property agreements can prevent installation or create expensive removal obligations.
• Ignoring insurance requirements: An insurer may require changes to the design, panel layout or maintenance plan.
• Assuming VAT is always zero: The domestic energy-saving-material relief does not normally apply to ordinary commercial installations.
• Counting all solar generation as a bill saving: Exported electricity must be valued at the export rate, not the import rate.

Business solar due-diligence checklist

Before signing a contract, confirm:

1. At least 12 months of electricity data has been analysed.
2. The self-consumption calculation uses interval data.
3. The roof has been structurally assessed.
4. Roof life is compatible with the solar project.
5. Asbestos risks have been investigated.
6. The insurer has reviewed the design.
7. Landlord and lender permissions are in place.
8. Planning status has been confirmed.
9. Building-control responsibilities are clear.
10. The DNO application has been submitted or approved.
11. Export restrictions are included in the model.
12. All capital and operating costs are identified.
13. The business has checked tax treatment.
14. Export income ownership is documented.
15. Panel, inverter and workmanship warranties are provided.
16. Inverter replacement is included in long-term forecasts.
17. The model includes degradation and downtime.
18. Finance or PPA termination terms have been reviewed.
19. Performance can be monitored remotely.
20. The contract explains what happens if projected savings are missed.

FAQ

Final verdict

Business solar panels can provide a strong financial return where the building has a suitable roof and substantial daytime electricity demand.

A typical commercial installation may cost £700–£1,200 per kWp and generate around 800–1,000kWh per kWp annually. Under favourable conditions, the investment can repay its cost within four to eight years and continue producing electricity for decades.

The most important figure is not the number of panels or total annual generation. It is the proportion of solar electricity the business can use itself.

Before proceeding, obtain a design based on half-hourly consumption data, confirm the roof’s condition, secure DNO approval and compare every quotation using consistent electricity-price, export and maintenance assumptions.

Solar can reduce grid consumption, but it does not replace the need for a competitive business electricity contract. The business will still import power outside solar-generation periods, so its remaining tariff should be reviewed alongside the solar investment.