Solar is one of the most popular energy improvements for commercial buildings - but it is not right for every situation, and not every solar project is structured correctly. Here is the complete framework we use to assess, design, and deliver solar PV for commercial operators.
Is solar right for your building?
Before spending a penny on solar panels, before doing anything else, here is what we would recommend: understand your building's actual energy profile first. When do you use the most electricity? How much of the solar generation will you actually consume on site? What is your roof condition and orientation?
The questions below are the starting point. But a well-structured solar project goes much further - covering financial integrity, technical risk, hardware quality, capital structure, regulatory compliance, and ongoing asset management. We cover all of it below.
Key questions to ask first
- What is your daytime electricity consumption profile?
- What percentage of generated power will you self-consume?
- Is your roof structurally suitable and in good condition?
- Do you have sufficient electrical capacity for the connection?
- What is the realistic payback period for your specific site?
- Have you considered battery storage to maximise self-consumption?
Financial Integrity and ROI
Solar PV can deliver strong financial returns - but only when the numbers are built on honest assumptions. We use independently verified generation models, not optimistic projections from installers with a vested interest in the sale.
For a typical 250 kWp commercial system, here is what realistic financial modelling looks like:
Capital Investment
£180k - £230k
For a 250 kWp system (installed)
Payback Period
4 - 6 years
Based on current electricity prices
Internal Rate of Return
14% - 18%
Over a 25-year asset life
Carbon Saved
22 tonnes CO₂
Per 100 kWp per year
These figures vary significantly by site. Self-consumption rate is the single biggest driver of financial return - a building that uses 80% of what it generates will see a very different payback than one that exports most of its generation. We model this before recommending anything.
We are supplier-agnostic and technology-agnostic. Our recommendations are based on what delivers the best return for your organisation, not what generates the best margin for an installer.
Technical Risk Management
The technical decisions made at the design stage determine whether a solar installation performs as modelled - and whether it creates problems down the line. There are four areas where we see projects go wrong.
Mounting strategy
Weighted ballast systems avoid roof penetrations and protect existing warranties - but add significant load. Anchored systems penetrate the roof membrane and require careful detailing. The right choice depends on your roof type, age, condition, and structural capacity. We specify what is right for your building, not what is easiest to install.
Roof integration
In-roof systems integrate with the roof covering and are often used on pitched roofs. On-roof systems sit above the existing surface. Both approaches have implications for weatherproofing, maintenance access, and future roof replacement. We assess which approach is appropriate and ensure the installation does not compromise your building envelope.
Structural verification
Wind and snow load calculations are not optional - they are a legal requirement. We commission independent structural assessments before any installation proceeds. A roof that looks adequate may not meet the additional loading requirements of a solar array, particularly on older industrial buildings.
Protecting existing warranties and future access
Solar installations can void roof warranties if not installed correctly. We review your existing warranties before specifying the installation approach. We also plan for future access - maintenance teams need to reach all parts of the roof safely, and solar arrays should not create permanent access problems.
Hardware Safety and System Uptime
Not all solar hardware is equal. The components you choose determine how the system performs over its 25-year life - and whether it causes problems for your building, your insurer, or your operations team.
Premium inverters
The inverter converts DC electricity from the panels into AC electricity for your building. It is the component most likely to require replacement over the system's life. We specify premium inverters from established manufacturers with proven reliability records and strong UK support networks - not the cheapest option available.
Smart optimisers
Panel-level optimisers provide individual visibility of each panel's performance. This means faults are identified quickly, partial shading from nearby structures or rooftop equipment has minimal impact on overall output, and maintenance teams can diagnose issues without manual inspection of every panel. On commercial roofs with complex shading profiles, optimisers can significantly improve system yield.
RC62 fire safety and insurance compliance
RC62 is the BFPSA guidance document covering solar PV fire safety. Compliance is increasingly required by commercial insurers - and some insurers will not cover buildings with solar installations that do not meet this standard. We design installations to RC62 requirements as standard, and we advise clients to notify their insurer before installation proceeds.
Capital Structure - Four Funding Routes
Capital cost does not have to be a barrier. There are four distinct funding routes for commercial solar, each with different implications for your balance sheet, your cash flow, and your long-term ownership position.
| Route | How it works | Balance sheet impact |
|---|---|---|
| CAPEX | You own the system outright from day one. Full capital expenditure, maximum long-term return. | Asset on balance sheet. Depreciated over asset life. Eligible for capital allowances. |
| Hire Purchase | Fixed monthly payments over an agreed term (typically 5-10 years). You own the asset at the end. | Asset and liability on balance sheet. Interest payments tax-deductible. No large upfront outlay. |
| Power Purchase Agreement (PPA) | A third party owns and maintains the system. You buy the electricity it generates at an agreed rate - typically below grid price. | Off balance sheet. No ownership, no maintenance responsibility. Lower savings than ownership routes. |
| Roof-Plus PPA | The PPA provider also funds roof repairs or replacement as part of the agreement. Useful where the roof needs work before solar can be installed. | Off balance sheet. Roof costs bundled into the PPA rate. Longer contract terms typically required. |
The right route depends on your organisation's capital position, tax situation, and appetite for long-term ownership. We work with your finance team to identify which structure delivers the best outcome - and we are not tied to any particular funding provider.
Regulatory Compliance and Operations Management
A solar installation is not a one-off project - it is a 25-year asset that requires ongoing management. The regulatory and operational framework needs to be in place from day one.
G99 grid connection
Any commercial solar installation above 16A per phase requires a G99 application to your Distribution Network Operator (DNO). This is a formal engineering process that can take 3-6 months and may require network reinforcement. We manage the G99 application process and liaise with the DNO on your behalf - including any technical studies required.
Lifecycle asset management
Solar panels are rated for 25 years, but they need active management to perform across that lifetime. We put in place operations and maintenance (O&M) contracts that cover routine inspection, cleaning, inverter monitoring, and fault response. We also use drone thermal imaging to identify underperforming panels and potential hotspots - faults that are invisible from ground level.
25-year warranty management
Quality solar panels carry performance warranties of 25 years - typically guaranteeing 80% of rated output at year 25. Inverters typically carry 10-year warranties, extendable to 20 years. We document all warranties at the point of installation and put in place a management process to ensure claims can be made if performance falls short. Most organisations never claim on warranties simply because they have no system to track them.
Independence - Why It Matters for Solar
Most solar projects are sold by developers who benefit from the sale. Their incentive is to install the largest system possible, using the products that give them the best margin. Our incentive is different - we are paid to give you the right advice, not to sell you a system.
| Area | Typical solar developer | Hawley Energy approach |
|---|---|---|
| System sizing | Maximise roof coverage to increase revenue | Size to your consumption profile - no more, no less |
| Hardware selection | Products with best installer margin | Products with best whole-life performance and support |
| Financial modelling | Optimistic projections to justify the sale | Conservative, independently verified assumptions |
| Funding route | Preferred finance partner (often tied) | Best route for your balance sheet and tax position |
| Post-installation | Limited ongoing support | Ongoing monitoring via Enerlyse, O&M management |
| Honest assessment | Rarely told solar is not right for their building | We tell you if solar does not stack up for your site |
Before doing anything else, here is what we would recommend: make sure whoever you speak to is truly independent and does not benefit from the route you choose to take. If solar does not make sense for your building, we will tell you - and point you towards what does.
Case Study - Manufacturing Facility
Project Example
400 kWp rooftop installation - manufacturing and distribution
400 kWp
System size
38%
Grid dependence reduction
£52,000
Year 1 savings
4.8 years
Simple payback period
CAPEX
Funding route used
The site had high daytime consumption from manufacturing processes, making it well-suited to solar. A structural survey confirmed the roof could carry a ballasted system without penetrations, protecting the existing roof warranty. G99 application was submitted 5 months before installation, avoiding delays. Smart optimisers were specified due to partial shading from rooftop plant. Year 1 performance came in 4% above the modelled projection.
This outcome was achievable because the project was designed correctly from the outset - with honest financial modelling, independent hardware specification, and a procurement process that selected the right contractor rather than the cheapest one.
Common Friction Points - and How to Handle Them
Most solar projects that stall or disappoint do so for predictable reasons. Here are the friction points we encounter most often - and how we address them.
DNO delays
G99 applications can take 3-6 months, and some require additional technical studies that extend this further. Organisations that do not start the DNO process early enough find their installation delayed by months. We submit G99 applications as soon as the system design is confirmed - not after the contractor is appointed.
Insurer pushback
Some commercial insurers have specific requirements for solar installations - or will not cover buildings with solar at all without prior notification. We advise clients to contact their insurer before installation begins, and we design installations to RC62 fire safety standards as standard. Surprises at the insurance renewal stage are avoidable.
Consumption profile mismatches
A solar system sized for a building's peak demand may export most of its generation if that demand is seasonal or shift-dependent. We analyse 12 months of half-hourly consumption data before sizing any system - ensuring the generation profile matches the consumption profile as closely as possible.
Switchgear limitations
Older switchgear may not be rated for the additional fault current that a solar installation introduces. This is a safety issue, not just a technical one. We assess your existing electrical infrastructure as part of the design process and include any required switchgear upgrades in the project scope and budget - not as a surprise variation after work has started.
Planning restrictions
Listed buildings, conservation areas, and some commercial premises have planning restrictions that affect what can be installed and how. We check planning requirements before design work begins. In some cases, permitted development rights cover commercial solar installations - but this cannot be assumed.
Next Step
Find out if solar is right for your building
Book a free energy review and we will assess whether solar PV makes commercial sense for your specific situation - with honest numbers, not optimistic projections.
Get in Touch