Commercial solar PV can cut a business’s electricity bills and carbon footprint, but whether it pays depends on roof suitability, how much of the power is used on site, and how the system is sized against the building’s grid connection. It is best treated as part of the building’s wider electrical infrastructure (survey, connection, maintenance and compliance) rather than as a panel-only purchase.
What does a commercial solar PV installation involve?
A commercial installation includes the panels and mounting system, inverters, DC and AC isolators, generation metering and the connection into the building’s distribution system. The electrical integration matters as much as the panels themselves. Three-phase supplies, load balancing, protective devices and safe isolation all affect how well and how safely the system operates.
Programme length depends on system size and complexity. A modest roof-mounted array on a straightforward industrial unit can be installed relatively quickly once approvals are in place, while larger systems with several inverters and long cable runs take longer. Grid connection approval for larger systems can add significantly to the overall timeline, so it should be started early.
The handover pack should include the electrical installation certificate and test results, schematic drawings, equipment data sheets and monitoring details. These documents show the installation meets BS 7671, which contains specific requirements for solar PV power supply systems, and give the facilities team a clear record for future maintenance and fault-finding.
How do you size a commercial solar PV system for an Essex business?
Sizing starts with half-hourly or interval consumption data, not roof area alone. A business that uses most of its electricity during daylight hours can justify a larger array than one with evening or overnight demand. Matching generation to daytime load maximises self-consumption, which is where the strongest savings sit.
Export is a secondary income stream. Rates paid for exported electricity are generally lower than the cost of imported power, so the business case should not rely on export alone. Roof structure, orientation, shading and available area set the practical limits on what can be installed.
Oversizing without a battery or load strategy can weaken the business case. If the system generates more than the building uses, the surplus is exported at a lower value. A site survey confirms what the connection can accept and whether the existing electrical infrastructure, such as the main switchboard or distribution boards, needs upgrading first.
What grid connection and approval steps apply to commercial solar PV?
Any generating system that runs in parallel with the public network must be notified to, or approved by, the distribution network operator (DNO) — across Essex, that is UK Power Networks. Smaller systems within set technical limits (up to 16A per phase) follow the G98 process, where the installer notifies the DNO after commissioning. Larger or more complex installations need a G99 application and approval before the system is connected.
The existing supply capacity and import/export limits shape the design. If the network cannot accept the proposed export, the system may need to be smaller, fitted with export limitation, or the business may need to fund network reinforcement. Battery storage can also change the connection picture by managing export and peak demand.
The practical sequence runs: survey, design, DNO application, installation, commissioning and notification. Each step should be documented. Energising a system without the correct approval creates a compliance risk and can cause problems on the local network.
Do you need planning permission or building regulations approval for solar panels on a business building?
Sometimes. Permitted development rights cover many roof-mounted installations on non-domestic buildings, subject to conditions on matters such as projection from the roof and siting. Listed buildings and sites in conservation areas need extra checks because the rules are tighter.
Building regulations points to confirm include structural loading and electrical safety. The roof must be able to carry the additional weight and wind loads, and the electrical installation must meet the relevant wiring standards. The local planning authority is the right place to confirm whether a specific project needs permission, and that position should be settled in writing before work starts.
What does commercial solar PV cost and what tax reliefs apply?
Commercial costs are quoted per project. The factors that move the figure include roof access, structural condition, inverter specification, cable runs, monitoring and any distribution board or supply upgrades. Like-for-like comparison between quotes is rarely straightforward, so check what each one includes.
The Annual Investment Allowance lets businesses deduct the full value of qualifying plant and machinery, up to £1 million a year, from profits before tax, and solar PV can qualify. VAT treatment differs between residential and commercial installations, so confirm the current position for your business with your accountant.
Panels typically carry long manufacturer warranties, while inverters usually have shorter cover and may need replacing during the system’s life. Payback is driven by self-consumption, export rates and electricity prices, all of which change over time, so treat any fixed payback figure with caution.
How is commercial solar PV maintained and how do you know it is performing?
Monitoring via the inverter portal shows live generation and alerts for faults or underperformance. A system that quietly loses output will erode the savings without anyone noticing, so the monitoring data should be reviewed regularly, not only when a problem is reported.
Periodic inspection and testing should cover both the DC side (strings, connectors and isolators) and the AC side (isolation, protective devices and earthing). Panel cleaning and vegetation management matter where soiling or shading reduces output. Solar should sit inside the building’s wider planned preventative maintenance schedule, alongside fixed wire testing and emergency lighting.
Record-keeping supports compliance and future due diligence. Certificates, DNO correspondence and maintenance reports should be stored with the rest of the building’s electrical records, which makes future inspections and property transactions simpler.
How can Delta First help with commercial solar PV?
Solar PV depends on the building’s electrical infrastructure, so it makes sense to plan it alongside the rest of your electrical work. Delta First’s directly employed commercial electrical team can assess your supply, distribution boards and three-phase capacity and carry out the upgrades a solar system depends on, and we can arrange solar PV design and installation through vetted specialist subcontractors.
Once the system is live, it can be brought into your commercial electrical maintenance regime and periodic commercial EICR testing, with records kept alongside your other compliance documentation through our full compliance management service. If you are also considering EV charging, the two can be planned together: see our EV charger installation service.
Key takeaways
- Commercial solar PV should be sized from the business’s actual consumption profile, not from roof area alone.
- Self-consumption drives the strongest savings; export is a secondary, lower-value income stream.
- Systems connected to the grid need DNO notification (G98) or prior approval (G99), and in Essex the DNO is UK Power Networks.
- Permitted development covers many roof-mounted installations on non-domestic buildings, but listed buildings and conservation areas need extra checks.
- The Annual Investment Allowance of up to £1 million a year can apply to qualifying solar PV expenditure; check VAT and tax treatment with your accountant.
- Solar is an electrical installation and should be monitored, tested and recorded alongside the rest of the building’s electrical systems.
Talk to Delta First
Delta First Building Services is a Colchester-based M&E contractor working across Essex, Suffolk and London, with commercial work in Norfolk. Our directly employed electrical team is supported by vetted specialist subcontractors where extra certification is needed, and we offer genuine 24/7 emergency cover. Get in touch to arrange a survey or quote.