G99 and G100 Applications for Commercial Solar in Manchester
G99 is the DNO generation-connection application required above 3.68 kW per phase and therefore for essentially every commercial solar system. G100 is the related export-limitation framework when the network cannot take full export. Incomplete applications and late DNO engagement are the usual causes of months of delay, extra cost, or export curtailment that hits ROI.
Bee Solar is a Manchester, Greater Manchester commercial installer that treats G99/G100 as core to every commercial installation, not an add-on form hunt. Timelines and reinforcement vary by local network conditions, with industrial estates with multiple solar systems as a constraint pattern.
Who it is for: UK commercial owners and property managers planning solar; not typical domestic G98 projects.
Risk/outcome at a glance:
- Delay: Months added when applications are late or incomplete.
- Reinforcement: Chargeable network works if local infrastructure is constrained.
- Export cap: G100 may limit what you can export, affecting ROI.
- Stalled business case: Grid connection issues can pause or kill a project after design freeze.
G99 is typically the longest-lead item after contract signature, so submitting immediately and checking feasibility early is a project-control decision, not admin trivia.
G99 vs G100 vs G98: which standard applies, and when one project needs both
Commercial systems almost always need G99. G98 is the simplified route up to 3.68 kW per phase and is almost never commercial. G100 governs export limitation schemes. A single project can be G99 plus G100-compliant equipment if the DNO approves generation but caps export. Understanding these UK Grid codes and compliance requirements is essential for a successful connection.
| Standard | What it is | Typical scale | What the DNO is deciding | Commercial relevance |
|---|---|---|---|---|
| G98 | Simplified connection route for small generation. | Up to 3.68 kW per phase. | Whether small generation can connect without detailed study. | Almost never commercial. |
| G99 | Formal application to connect generation equipment. | Above 3.68 kW per phase; essentially all commercial systems. | Capacity, voltage, transformer loading, and network impact. | Permission to connect generation. |
| G100 | Export limitation framework when the network cannot accept full export. | Used where generation exceeds local network capacity. | How much you may export at any moment. | Often offered instead of outright refusal. |
Same project rule: G99 = permission to connect generation. G100 = how much you may export at any moment. One project can require both.
G100 is often offered instead of outright refusal when the network cannot accept full export.
What a G99 application covers for commercial plant (Type A and Type B)
G99 is the formal application to the local DNO to connect generation equipment, with assessment of capacity, voltage, and transformer loading.
Type A: Systems up to 50 kW connected at low voltage (source only).
Type B: Larger or more complex connections (source only; no extra kW bands invented).
For Type A installations on warehouse and retail units, the next critical step once the connection path is clear is choosing the right solar technology.
The outcome you want is a DNO decision path (accept, reinforce, and/or impose G100), not a DIY form tutorial. Official G99 forms and guidance exist via DNO / National Grid connections resources; the installer normally completes and submits them (per Generation (G99), connections.nationalgrid.co.uk).
Complexity note: Type B cases involve more engineering and DNO scrutiny than standard Type A connections.
When a DNO offers G100 export limitation—and how storage changes the economics
G100 is the standard for export limitation schemes used when the DNO cannot accept full export but may still approve the connection. G100-compliant smart inverters provide real-time export monitoring and millisecond throttle to stay within agreed limits.
Decision/trade-off:
- Full export: No curtailment, but may not be approved on constrained networks.
- G100 limit: Connection in constrained areas, but possible curtailment at high generation and low on-site load.
- G100 + storage: Divert generation that would be curtailed into charge; increasingly standard for larger commercial systems in urban and industrial areas.
Battery storage can make export limits commercially viable. In Manchester and Greater Manchester, urban-industrial constraint patterns make this trade-off common, but local network conditions always decide.
G100 is not an optional extra after design freeze. Export limits should be designed in, with storage as an economics fix, not a technical afterthought.
How Bee Solar manages G99 and G100 as a productised commercial service
Bee Solar manages G99 and G100 as a core part of every commercial installation. In-house electrical engineering prepares and submits documentation, liaises with DNO engineers, and tracks through to approval.
- Assess/feasibility: Early DNO engagement and grid capacity check.
- Design to DNO requirements: System design aligned with connection standards.
- Complete pack: All required documents prepared in-house.
- Submit: G99 submitted immediately on contract signature (longest-lead item).
- DNO assessment: Tracking and responding to DNO questions.
- Possible G100 and/or reinforcement: Managing the outcome path.
- Install/commission alignment: Ensuring the installed system matches the approved connection.
Inclusions: Standalone pre-application enquiry for first-time explorers: indicative grid capacity and connection costs before financial commitment.
Suitability: Commercial owners/managers, including Manchester-area commercial solar; not typical domestic G98.
Limitations: DNO may still require chargeable works or export limits; no promised approval times.
Next step: Free site survey and detailed itemised quotation. Enquire about a pre-application if you are not ready to contract.
Managers should track completeness and DNO questions, not hunt PDFs. Bee Solar owns submission and liaison.
The G99 application pack property managers should insist is complete
Missing or incorrect documentation is the most common cause of DNO delay. The installer prepares the pack; the client tracks progress and asks the right questions.
Mandatory pack contents:
- Completed G99 application form.
- Single-line diagram.
- Inverter specifications and G99 type-test certificates.
- Protection settings.
- Earthing arrangement diagram.
Completeness of the pack matters more than knowing where the National Grid G99 page lives.
What actually drives time and money: DNO assessment versus network reinforcement
Two clocks run on a G99 application. Typical DNO assessment takes about four to six weeks in uncongested networks; twelve weeks or more if reinforcement is required (network-dependent; no guarantees). The typical G99 application fee is about £250–£500 for administrative assessment only. Reinforcement (transformer upgrade, reconductoring, etc.) can be much higher and in extreme cases tens of thousands of pounds, changing project economics.
| Layer | What it covers | Indicative scale |
|---|---|---|
| DNO assessment | Administrative review and connection decision. | About £250–£500; about four to six weeks in uncongested networks. |
| Network reinforcement | Chargeable network works (transformer upgrade, reconductoring, etc.). | Can be much higher; in extreme cases tens of thousands of pounds; twelve weeks or more. |
When economics change: If reinforcement costs are extreme, the project business case may need revisiting. Solar financing can cover the project including DNO reinforcement costs, spreading investment (source-safe note; no named finance product).
Industrial estates and constrained urban-industrial networks (Manchester-area commercial audience) are where reinforcement or G100 is more likely as a pattern. The application fee is not the grid-connection budget; reinforcement and export limits are the real commercial variables.
Pre-application enquiry versus committing to a full commercial design
Early DNO engagement at feasibility is the most effective way to avoid surprises. Bee Solar offers a standalone pre-application enquiry: indicative grid capacity and connection costs before financial commitment.
Choose pre-application enquiry if: You want indicative capacity and cost before locking the business case.
Choose free site survey and itemised quotation if: You are ready to plan the install.
Expected outcome: An approval path (connect / connect with G100 / reinforce) before capex lock-in.
Limitations: Indicative, not a binding DNO offer. The DNO still decides.
Pre-application is a productised risk-reduction service, not "fill in a form when you feel like it."
Frequently Asked Questions
- What is a G99 application for commercial solar?
- What is a G100 application?
- What is the difference between G99 and G100?
- Do commercial solar systems always need G99 rather than G98?
- Can one commercial project need both G99 and G100?
- Where is the official G99 form and who should submit it?
- How long does a G99 DNO assessment usually take?
- What documents are required for a G99 application?
- When would a DNO require G100 export limitation or network reinforcement?
- Should we request a pre-application enquiry before committing to a Manchester commercial solar design?
Why G99 and G100 sit on the critical path of a Manchester commercial solar project
G99 is the DNO generation-connection application required above 3.68 kW per phase, which means it applies to essentially every commercial solar system. G100 is the related export-limitation framework used when the network cannot accept full export. These standards, not panel choice, usually determine whether a commercial install proceeds on time and on budget.
Incomplete applications and late DNO engagement are the usual causes of months of delay, extra cost, or export curtailment that hits ROI. Bee Solar, a Manchester and Greater Manchester commercial installer, treats G99 and G100 as core to every commercial installation, not an add-on form hunt. This meticulous approach is vital given the rising demand for commercial solar across the UK, which puts additional pressure on regional grid capacity.
Timelines and reinforcement vary by local network conditions, and industrial estates with multiple solar systems are a common constraint pattern. G99 is typically the longest-lead item after contract signature, so submitting immediately and checking feasibility early is a project-control decision, not admin trivia.
UK commercial owners and property managers planning solar should treat grid-connection risk as a managed service, not paperwork after design freeze; this is not a typical domestic G98 project.
Delaying the application by even a few weeks can push the whole installation past a planned commissioning window (per G99 Grid Connection for Commercial Solar: Complete Guide, ececoenergy.com), which is why the application should be treated as the first task after sign-off, not a later stage.
G99 vs G100 vs G98: which standard applies, and when one project needs both
Commercial systems almost always need G99; G98 is the simplified route up to 3.68 kW per phase and is almost never commercial; G100 governs export limitation schemes. A single project can be G99 plus G100-compliant equipment if the DNO approves generation but caps export. Navigating these distinctions successfully relies on a solid grasp of the UK Grid codes and compliance framework.
| Standard | What it is | Typical scale | What the DNO is deciding | Commercial relevance |
|---|---|---|---|---|
| G98 | Simplified connection process | Up to 3.68 kW per phase | Small-scale generation connection | Almost never commercial |
| G99 | Formal generation connection application | Above 3.68 kW per phase | Capacity, voltage, transformer loading | Default route for commercial systems |
| G100 | Export limitation framework | Any system with export limits | How much may be exported at any moment | Often added when full export is refused |
G100 is not a substitute for G99; it is often offered instead of outright refusal when the network cannot accept full export. G99 means permission to connect generation, while G100 means how much you may export at any moment.
The practical implication is that a project team needs to plan for both: the G99 application secures the right to generate, and the G100 scheme defines the operating envelope within which that generation must stay. A system designed with only one standard in mind may face rework or unnecessary curtailment.
What a G99 application covers for commercial plant (Type A and Type B)
G99 is the formal application to the local DNO to connect generation equipment, covering assessment of capacity, voltage, and transformer loading. The outcome is a DNO decision path: accept, reinforce, or impose G100, rather than a DIY form tutorial.
Type A: systems up to 50 kW connected at low voltage (source only). These are the most common commercial installations, typically on warehouse roofs, retail units, and small industrial buildings, where choosing the right solar technology is key to maximising returns.
Type B: larger or more complex connections (source only). These involve more engineering, longer DNO assessment, and usually a higher likelihood of reinforcement or export constraints.
Official G99 forms and guidance exist via DNO and National Grid connections resources (per Generation (G99), connections.nationalgrid.co.uk). The installer normally completes and submits them, which is why the Type A versus Type B split matters: Type B systems involve more engineering and DNO scrutiny.
Knowing which type applies early helps set realistic expectations on timeline and budget, and it determines the level of electrical design evidence the DNO will expect in the application pack.
When a DNO offers G100 export limitation—and how storage changes the economics
G100 is the standard for export limitation schemes used when the DNO cannot accept full export but may still approve the connection.
G100-compliant smart inverters provide real-time export monitoring and millisecond throttle to stay within agreed limits.
The trade-off is connection in constrained areas versus possible curtailment at high generation and low on-site load.
Battery storage can divert generation that would be curtailed into charge, making storage increasingly standard for larger commercial systems in urban and industrial areas like Manchester and Greater Manchester. Rather than losing the surplus entirely, a battery bank captures those kilowatt-hours and discharges them when on-site demand rises or when export becomes permissible.
G100 is not an optional extra after design freeze; export limits should be designed in, with storage as an economics fix, not a technical afterthought.
When choosing between insisting on unconstrained export, accepting G100 limits, or pairing limitation with batteries, the last option often unlocks the largest viable system. The key modelling question is whether the curtailment losses under G100 exceed the cost of adding storage, and this calculation should be done before the G99 application is submitted, not after the DNO responds.
How Bee Solar manages G99 and G100 as a productised commercial service
Bee Solar manages G99 and G100 as a core part of every commercial installation; in-house electrical engineering prepares and submits documentation, liaises with DNO engineers, and tracks through to approval. We submit G99 immediately on contract signature because it is the longest-lead item.
For first-time explorers, we offer a standalone pre-application enquiry service that provides indicative grid capacity and connection costs before financial commitment.
- Assess and feasibility check
- Design to DNO requirements
- Complete the application pack
- Submit to the DNO
- DNO assessment
- Possible G100 and/or reinforcement
- Install and commission aligned with approval
This service suits commercial owners and managers, including Manchester-area commercial solar; it is not for typical domestic G98 projects.
The DNO may still require chargeable works or export limits, and we cannot promise approval times. What we can promise is that the application is submitted early, the documentation is complete, and any DNO questions are answered promptly so that the clock is not paused waiting on the applicant.
Request a free site survey and detailed itemised quotation, or enquire about a pre-application where you are not ready to contract.
The G99 application pack property managers should insist is complete
Missing or incorrect documentation is the most common cause of DNO delay. This is the mandatory source list for a complete G99 pack:
- Completed G99 application form
- Single-line diagram
- Inverter specifications and G99 type-test certificates
- Protection settings
- Earthing arrangement diagram
The installer prepares these documents; the client tracks progress and asks the right questions. Completeness of the pack matters more than knowing where the National Grid G99 page lives.
A practical way to keep the process moving is to agree at the outset which party responds to DNO queries and within what timeframe. Every day spent chasing a missing drawing is a day added to the overall project schedule.
What actually drives time and money: DNO assessment versus network reinforcement
There are two clocks:
- Typical DNO assessment: about four to six weeks in uncongested networks.
- Assessment with reinforcement required: twelve weeks or more, depending on the network.
Cost has two layers:
- Typical G99 application fee: about £250 to £500, covering administrative assessment only.
- Reinforcement costs (transformer upgrade, reconductoring, etc.): can be much higher, reaching tens of thousands of pounds in extreme cases.
The application fee is not the grid-connection budget; reinforcement and export limits are the real commercial variables. Industrial estates and constrained urban-industrial networks, common in Manchester-area commercial settings, are where reinforcement or G100 is more likely as a pattern. A site on an estate where several neighbouring units already export solar is more likely to face a constraint or a reinforcement quote than a site on a lightly loaded feeder.
Solar financing can cover the project including DNO reinforcement costs, spreading the investment, though these figures are not a Bee Solar quote or a total project cost. The point is that reinforcement expense should be treated as a feasibility item to be investigated early, not an emergency cost discovered at the end of the design process.
Pre-application enquiry versus committing to a full commercial design
Early DNO engagement at feasibility is the most effective way to avoid surprises. Bee Solar offers a standalone pre-application enquiry providing indicative grid capacity and connection costs before financial commitment.
For those ready to plan the install, request a free site survey and itemised quotation. The expected outcome is an approval path: connect, connect with G100, or reinforce, before capex lock-in.
This is indicative only, not a binding DNO offer; the DNO still decides.
Pre-application is a productised risk-reduction service, not a form to fill in when you feel like it. Choose it before committing to a full commercial design in Manchester if you want to lock the business case with confidence.
The cost of a pre-application enquiry is typically negligible compared with the cost of redesigning a system that the DNO will not accept unconstrained (per Generation (G99), connections.nationalgrid.co.uk), and it gives the project team a documented basis for the financial model.
Frequently Asked Questions
What is a G99 application for commercial solar?
A G99 application is the formal request to the DNO for permission to connect generation equipment above 3.68 kW per phase. It covers essentially every commercial solar system and includes technical assessment of capacity, voltage, and transformer loading.
What is a G100 application?
A G100 application is the export limitation framework used when the DNO cannot accept full export from a system. It requires G100-compliant equipment that throttles export in real time, and it is often offered instead of outright connection refusal.
What is the difference between G99 and G100?
G99 is permission to connect generation equipment; G100 is the limit on how much you may export at any moment. They are not alternatives: a single project can need both, with G99 approving connection and G100 capping export.
Do commercial solar systems always need G99 rather than G98?
Yes, commercial systems almost always need G99 because they exceed 3.68 kW per phase. G98 is the simplified route for small domestic-scale systems and is almost never relevant to commercial projects.
Can one commercial project need both G99 and G100?
Yes, a single project can be G99 plus G100-compliant equipment if the DNO approves generation but caps export. This is common in constrained urban and industrial networks where the grid cannot accept full export.
Where is the official G99 form and who should submit it?
The official G99 form is available through DNO and National Grid connections resources (per Generation (G99), connections.nationalgrid.co.uk). Your installer normally completes and submits it, and you should track completeness rather than hunting for PDFs yourself.
How long does a G99 DNO assessment usually take?
A typical G99 assessment takes four to six weeks in uncongested networks. It can extend to twelve weeks or more if network reinforcement is required, depending on local grid conditions.
What documents are required for a G99 application?
The mandatory pack includes the completed G99 application form, single-line diagram, inverter specifications and G99 type-test certificates, protection settings, and earthing arrangement diagram. Missing documents are the most common cause of delay.
When would a DNO require G100 export limitation or network reinforcement?
A DNO requires G100 export limitation when the local network cannot accept full export without overloading. Reinforcement is required when capacity, voltage, or transformer loading falls short; both are more likely in constrained industrial estates in Manchester and Greater Manchester.
Should we request a pre-application enquiry before committing to a Manchester commercial solar design?
Yes, a pre-application enquiry is the most effective way to avoid surprises. It provides indicative grid capacity and connection costs before financial commitment, giving you an approval path before capex lock-in.
Further Reading
A selection of official sources on G99, G100 and grid connections for commercial solar: