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On-Site Energy Generation UK: Legal Risks & Rules

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Written by Brad Askew Solicitor (non-practising)
Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice.
Updated June 2026 · England & Wales
More UK businesses are looking at generating their own power on site, whether to cut running costs, hit sustainability targets, or reduce exposure to volatile wholesale prices. The technology choices are wide ranging, from rooftop solar and small wind to biomass boilers and combined heat and power units. What often gets less attention is the legal and regulatory framework sitting behind these projects. Planning, environmental rules, grid connection, and the contracts you sign with installers and operators can all reshape the economics of a scheme, and in some cases sink it entirely. This guide walks through the main legal considerations a commercial operator should think about before committing to an on-site generation project in England and Wales, and flags the questions worth asking your suppliers, advisers and landlord before anything gets bolted to the roof.

Overview

On-site energy generation, sometimes shortened to OSEG, simply means producing electricity or heat at the premises where it is used rather than buying everything from the grid. For a commercial user this might look like solar photovoltaic panels across a warehouse roof, a wind turbine on a rural industrial site, a biomass boiler feeding a process, or a combined heat and power unit that generates electricity and captures the waste heat for space heating or hot water.

Some installations are sized to serve the occupier's own demand, while others are large enough to export surplus electricity back to the public network. The scale and technology drive almost every legal question that follows, including whether planning consent is needed, whether an environmental permit applies, how the connection to the grid is regulated, and what the supplier contracts need to cover. Treating it as purely a procurement decision tends to miss material legal and operational risks.

Key steps

  1. Check whether planning permission is required. Some smaller installations fall within permitted development rights, but larger schemes, listed buildings, sites in conservation areas, or ground-mounted arrays commonly need a formal application to the local planning authority. Speak to the planning team early, since conditions attached to consent can affect layout, noise limits and operating hours.
  2. Identify any environmental permits or exemptions. Biomass and combustion based systems in particular may fall within the environmental permitting regime overseen by the Environment Agency, with rules on emissions, waste and water. Even solar and wind projects can trigger ecological, noise or flood risk considerations, so a proportionate environmental review is sensible before design is finalised.
  3. Sort out your grid connection position. If the system will connect to the public network, or export surplus power, you will need to engage your Distribution Network Operator. Application timelines, capacity constraints and network reinforcement costs can be significant, and should be understood before the capital spend on equipment is committed.
  4. Review the installer and operation contracts carefully. Look closely at performance guarantees, warranties, liability caps, insurance obligations, and what happens if output falls short or equipment fails. Maintenance responsibilities, response times for faults, and exit arrangements at the end of the term all deserve scrutiny rather than being left to the standard terms.
  5. Think about property, tax and accounting implications. If you lease the premises, check the lease for restrictions on alterations, rooftop use, and reversion of improvements. Consider who will own the equipment, how it will be financed, whether a power purchase arrangement is involved, and how the asset and any incentives should be treated for tax and accounting purposes.

Common questions

If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £89.

Common questions

Q Do I always need planning permission for solar panels on a commercial building?
Not always. Some commercial solar installations are covered by permitted development rights, particularly smaller rooftop schemes on non-listed buildings outside sensitive areas. Larger arrays, ground-mounted systems, projects on listed buildings, and installations in conservation areas or national parks commonly need a full application. The safest approach is to ask your local planning authority to confirm the position in writing before ordering equipment.
Q When does an environmental permit apply to on-site generation?
Environmental permitting tends to bite where combustion, waste handling, or emissions to air or water are involved. Biomass boilers, gas fired CHP units and certain anaerobic digestion setups often fall within the regime, while purely electrical systems like solar or wind generally do not. The Environment Agency publishes thresholds and standard rules, and it is worth checking these during the design stage rather than after installation.
Q What is a grid connection agreement and why does it matter?
A grid connection agreement is the contract with your Distribution Network Operator that governs how your installation connects to, and interacts with, the public electricity network. It sets out technical conditions, protection requirements, metering arrangements, and any limits on import or export. The cost of network upgrades and the available capacity in your area can materially affect project viability, so treat this as a core commercial document.
Q What should I look for in the contract with the installer?
Focus on what happens when things go wrong. Performance guarantees should tie to realistic output figures, warranties should cover both equipment and workmanship for a sensible period, and liability caps should be proportionate to the risks. Check maintenance obligations, response times, insurance requirements, and the consequences of delay or defective work. Dispute resolution and termination rights also deserve careful review.
Q We lease our premises. Does that change anything?
Significantly, yes. Most commercial leases restrict alterations, rooftop use, and fixing equipment to the structure. You may need landlord consent, a licence for alterations, or a separate agreement for rooftop rights, and the lease may dictate what happens to the equipment at the end of the term. Read the lease before approaching installers, and factor any negotiations with the landlord into the project timeline.
Q Can I sell surplus electricity back to the grid?
In many cases yes, but the commercial route depends on your connection agreement, your meter arrangements, and the supplier or trading party you contract with. Export tariffs and power purchase agreements vary widely in price, length and flexibility. Read the export contract alongside the grid connection documents so that technical limits and commercial terms actually line up.
Q Who is responsible if the system underperforms or fails?
That depends on the contractual structure. Responsibility can sit with the installer under a performance guarantee, with a maintenance provider under a service contract, with the equipment manufacturer under a warranty, or with you as operator. Clarifying this before signing, and making sure the different contracts dovetail rather than leave gaps, is one of the more common issues we see businesses raise after the event.
If you're dealing with this kind of situation, a call with an experienced legal adviser can help you work out the right next step — from £89.

Sources

This guide is based on primary UK law and official guidance.

Brad Askew, Solicitor (non-practising)

Written & reviewed by

Brad Askew Solicitor (non-practising)

Brad is on the roll of solicitors of England & Wales but does not hold a practising certificate and does not provide legal advice. LegalDocuments.co.uk is not a law firm and does not provide regulated legal advice.

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Legal disclaimer
This article is for general information only. It is a tool to help you find your way — not legal advice, and not a substitute for speaking to a qualified adviser about your situation.