Grid Connection Process Explained: How Solar Systems Are Approved and Integrated
Author: Steve Fairless
Originally Published: 1st May 2026 · Updated: 3rd September 2026
Solar Grid Connection Process: The Short Answer
In Great Britain, small generating installations can use different engineering-recommendation routes depending on their registered capacity and configuration. The current ENA G98 Issue 2, published in April 2026, applies to qualifying micro-generators up to and including 16 A per phase. Installations outside G98 conditions normally follow G99 or another applicable connection route. The DNO process should be identified during design because it can affect inverter size, export limits, battery strategy and project timing.
- G98 is a 16 A-per-phase route. Current ENA G98 Issue 2 covers qualifying fully type-tested micro-generators up to and including 16 A per phase.
- On a nominal 230 V single-phase supply, 16 A is approximately 3.68 kW AC. On three phase, 16 A per phase is approximately 11.04 kW in total if appropriately balanced.
- Qualifying G98 installations are normally connect-and-notify. Current GOV.UK guidance says the relevant notification should be submitted within 28 days of installation.
- Apply-to-connect projects need the network step before installation. GOV.UK currently points installers to G99, or G100 where export is limited, for applicable pre-connection applications.
- Connection timing is not one fixed number. Current government guidance gives 45 days for low-voltage and 65 days for high-voltage apply-to-connect responses, with a 10-days-or-less fast-track route for qualifying integrated microgeneration and storage.
- Export capacity and generation capacity are different. We design the inverter, battery and export-control strategy around the actual DNO position rather than the panel count alone.
What does the DNO actually do?
The Distribution Network Operator owns and operates the local electricity distribution network. It is not normally your electricity supplier. The DNO's job in a generation connection is to make sure the proposed equipment can operate without creating unacceptable voltage, protection or network-security problems.
For our domestic solar and commercial solar projects, we identify the relevant DNO and connection route before finalising equipment. That prevents a system being sold around an inverter capacity that later conflicts with the available network connection.
G98 in 2026: the threshold is 16 A per phase
The current G98 engineering recommendation covers micro-generators up to and including 16 A per phase that meet the relevant technical requirements. At a nominal 230 V:
| Supply | 16 A-per-phase equivalent at 230 V | Meaning |
|---|---|---|
| Single phase | 3.68 kW | Common G98 single-phase threshold. |
| Three phase | 11.04 kW total | Equivalent if generation is appropriately balanced across three phases. |
The familiar 3.68 kW number is therefore the approximate single-phase AC threshold corresponding to 16 A at 230 V. It is not a universal maximum solar-array size and it is not simply the total DC wattage printed on the panels.
Current ENA Connection Documents We Design Against
| Document | Current issue | Published | Why it matters |
|---|---|---|---|
| EREC G98 | Issue 2 | April 2026 | Current micro-generation recommendation for qualifying fully type-tested equipment up to and including 16 A per phase. |
| EREC G99 | Issue 2 | March 2025 | Current generation-connection recommendation for installations outside the G98 route. |
| Distributed Generation Connection Guide: G98 & G99 | Issue 3 | March 2026 | Current ENA guide used to navigate the application and notification routes. |
For us, the important point is not the document number on its own. We use the current connection route to decide what equipment can be specified, when the DNO needs information and whether export control or a different inverter arrangement is required.
Why DC panel kWp and grid-connection capacity are different
A solar array might have, for example, 5 kWp of modules connected to an inverter whose registered AC generating capacity is lower. The network application is concerned with the generating equipment and how it can interact with the grid, not just the sum of module nameplate powers.
That distinction is important because people often ask whether “anything over 3.68 kW needs G99”. The correct answer depends on the registered generation arrangement, phases and equipment. A larger DC array can sometimes sit behind a lower AC inverter capacity, while batteries or multiple inverters can change the registered-generation picture.
G98 is generally a connect-and-notify route
For an eligible single-premises G98 installation, the installer can normally connect the compliant system and then notify the DNO. Current GOV.UK guidance says the relevant G98 application/notification should be submitted within 28 days of commissioning under the connect-and-notify route.
That does not mean the network can be ignored until the end. The installer still needs to verify that the system is genuinely within the G98 route, use compliant equipment and submit accurate information after commissioning.
When G99 becomes relevant
G99 covers generating installations outside the G98 micro-generation conditions. In domestic solar, this can include systems with higher registered capacity, multiple devices or configurations that do not qualify for G98. Commercial installations commonly use G99 because they are larger and frequently three-phase.
Unlike the straightforward G98 connect-and-notify process, G99 commonly involves an application and DNO assessment before the generating plant is connected. The precise application route, technical studies and response time depend on the scale and network.
There is no single guaranteed G99 approval time
Generic claims such as “G99 always takes four weeks” are unreliable. A small application on a strong local network may be straightforward; a larger connection can need network studies, revised protection settings, export limitation, reinforcement or a formal connection offer. DNO workload and the quality of the application also affect progress.
We therefore separate the physical installation programme from the network-approval programme. The roof work may take days while the connection process takes materially longer.
Current Connection Timing References
| Route | Current published timing | How we use it |
|---|---|---|
| G98 connect-and-notify | Notify within 28 days of installation | Useful for qualifying installations that can be connected before the formal notification is submitted. |
| Apply-to-connect — low voltage | DNO in touch within 45 days | A planning reference, not a promise that every project will be fully approved and ready to build inside that period. |
| Apply-to-connect — high voltage | DNO in touch within 65 days | Relevant to larger or more complex connections where network assessment can be more involved. |
| Qualifying integrated microgeneration + storage fast track | 10 days or less | Available only where the specific fully type-tested configuration and application route meet the fast-track conditions. |
We programme the project around the actual route returned by the DNO. These published windows help set expectations, but they do not replace the connection offer or the conditions attached to a specific site.
What information goes into a connection application?
The required information varies by route and scale but can include site details, supply characteristics, phase arrangement, generating-unit make and model, registered capacity, protection data, single-line diagrams, battery information and export-limitation arrangements. Using approved/certified equipment and accurate technical data reduces avoidable queries.
The information submitted should match the final installed system. Substituting an inverter or adding storage without checking the approved design can invalidate assumptions made during the network assessment.
Export limit is not the same as generation capacity
A system can be capable of generating more power internally than the DNO permits it to export. An export limitation scheme can monitor power flow at the grid connection point and control generation or storage so export stays within the agreed limit.
| Term | What it describes |
|---|---|
| DC array capacity (kWp) | Sum of the solar-module nameplate power. |
| Registered generation capacity | Capacity of generating equipment considered for the connection route. |
| Export capacity | Maximum power permitted to flow from the site to the network. |
| Self-consumption | Generation used behind the meter instead of exported. |
This distinction allows some sites to install more generation for on-site use while respecting a constrained network export. The engineering and approved control scheme have to be correct; export limitation is not just a software slider chosen after installation.
How batteries change the network calculation
Batteries can charge from solar, charge from the grid and discharge back into the property or grid depending on the configuration. From a DNO perspective, that means the battery inverter may contribute to the generating capacity or export capability considered in the application.
Our battery-storage designs therefore include the battery in the connection strategy from the start. Adding a battery later can require a new notification or application even when the PV modules themselves are unchanged.
Three-phase supplies and the 16 A threshold
On a three-phase system, G98's 16 A-per-phase threshold corresponds to about 11.04 kW total at 230 V per phase if the generation is suitably balanced. That does not mean every 11 kW three-phase installation automatically qualifies; it still has to meet the relevant G98 conditions and device requirements.
Commercial sites can also have existing generators, CHP, EV infrastructure or battery systems that affect the combined connection assessment. The whole site must be considered rather than assessing the new PV in isolation.
What happens if the DNO offers less export than requested?
The DNO may propose a lower export capacity or require an export-limitation scheme where the local network cannot accept the requested export without reinforcement. The customer then has choices: redesign the system, accept the limit, add control/storage, or in some cases pay for network work where that is economically justified.
An export limit does not necessarily make solar a poor investment. A daytime-load-heavy business can use much of its generation behind the meter, while a household battery can capture some midday surplus. But the financial model needs to use the real agreed export capability.
Does DNO approval automatically qualify you for SEG?
No. Grid connection and export payment are separate processes. The DNO deals with the safe network connection. The Smart Export Guarantee is an electricity-supplier scheme under which an eligible generator applies to an SEG licensee for payment for metered exports.
Ofgem requires actual export measurement for SEG and suppliers set their own rates and contract conditions. DNO registration is therefore part of the technical compliance picture, while the export tariff is a commercial agreement with a supplier.
What about MCS certification?
MCS certification is also separate from the DNO's engineering decision, but it is central to the consumer and export pathway for typical domestic solar. The current MIS 3002 standard covers system design, performance estimation, technical information and installation requirements.
A professional project coordinates all three strands: MCS technical/certification requirements, DNO connection requirements and the customer's eventual SEG application where export payment is desired.
Common grid-connection mistakes
| Mistake | Consequence |
|---|---|
| Assuming panel kWp equals G98 capacity | Can put a project on the wrong connection route. |
| Applying after equipment is changed | DNO assessment may no longer match the installed system. |
| Ignoring batteries | Combined generating/export capability can be understated. |
| Treating an export limit as a generation limit | Can unnecessarily undersize useful behind-the-meter generation. |
| Promising a fixed G99 approval time | Creates unrealistic project expectations. |
| Confusing DNO approval with SEG | Technical connection does not create an export-payment contract. |
These problems are avoidable when connection engineering is completed before procurement and the final installed equipment is checked against the application.
Can you install more panels later?
Yes, but an extension can change the network position. Adding modules to an existing inverter may leave registered AC capacity unchanged, while adding another inverter can increase it. Battery retrofits can also affect the connection. Before extending an existing array, check the original DNO paperwork and current equipment.
This is one reason we recommend keeping MCS certificates, commissioning data, single-line diagrams and DNO correspondence with the property records.
How grid connection affects solar ROI
The connection decision can affect export revenue, inverter selection, battery use and future expansion. A design that assumes unrestricted export but is later capped may overstate revenue. Conversely, a project with strong self-consumption can remain attractive even under a modest export limit.
The financial model should therefore be updated after the network route and any export limitation are known. We do not treat the DNO step as administrative paperwork added after the sales calculation.
Our grid-connection workflow
- Confirm supply type, phases and existing generation/storage.
- Select the intended inverter, battery and control architecture.
- Calculate registered capacity and identify the G98/G99 route.
- Submit any required pre-connection application before installation.
- Design around any DNO export limit or conditions.
- Install and commission the approved equipment.
- Submit G98 notification or G99 completion information as required.
- Provide customer records for MCS/SEG and future upgrades.
Customers planning a system can request a solar quotation. We use the intended equipment and supply details to identify the likely connection route and flag anything that could affect timing before the installation programme is agreed.
Final answer: what is the solar grid-connection process?
First, the installer determines whether the proposed generating equipment qualifies for G98 or needs a G99 route. G98 micro-generation is based on up to and including 16 A per phase and generally follows connect-and-notify, while larger or non-qualifying installations require the appropriate G99 application and DNO assessment. The final installed system is then commissioned, documented and registered in line with the applicable route.
The key is to distinguish panel DC capacity, registered AC generation, export capacity and the customer's export tariff. They are related but not interchangeable. When those four concepts are clear, the connection process becomes much easier to design correctly.
Need Us to Check the Grid Route Before You Choose the Inverter?
We can assess the proposed PV, battery and export arrangement against the supply and likely DNO route before the final equipment specification is fixed.
Request a tailored quote from Sustainable Energy Engineering.
