DNO Grid Connection for Commercial Solar
DNO grid connection for UK commercial solar PV — G99 process, current lead times, capacity constraints by region.
DNO grid connection for UK commercial solar PV — G99 process, current lead times, capacity constraints by region.
Introduction
DNO grid connection for UK commercial solar PV — G99 process, current lead times, capacity constraints by region. This post sets out the current state of play for UK commercial property owners, facilities directors, and finance teams considering this topic in 2026.
Market context
The UK commercial solar PV market entered a sustained growth phase from 2021 onwards as grid retail electricity prices more than doubled, corporate and public-sector net zero commitments brought forward decarbonisation timelines, and the supply chain matured to support installations at scale. UK installed commercial solar capacity exceeded 2.5 GW in 2024 and is projected to add 1 GW per year through 2030 under current policy trajectories.
Against that market backdrop, the topic of this post sits at the centre of the practical decisions UK commercial property owners face in 2026. The economics, the compliance environment, and the financing landscape have all shifted in ways that materially affect commercial solar project planning.
Detailed analysis
Three primary factors drive the current state of the UK commercial solar market relevant to dno grid connection for commercial solar. First, the underlying economics — UK commercial grid retail electricity averages 22–28p/kWh in 2026 versus commercial solar LCOE of 6–10p/kWh, meaning every kWh self-consumed from on-site generation saves the marginal grid retail tariff. Second, the regulatory environment — UK building regulations, MEES (Minimum Energy Efficiency Standards), SECR (Streamlined Energy and Carbon Reporting), and net zero commitments increasingly require demonstrable energy efficiency and Scope 2 emissions reductions. Third, the financing environment — three distinct funding routes (capital purchase plus AIA, asset finance, PPA) plus capital grants for public sector and manufacturing estates.
For UK commercial decision-makers, this means the 2026 commercial solar market is more mature, more scrutinised, and more strategically embedded than at any previous point. Generalist solar installers running domestic work as their core business and commercial as a side line are increasingly outcompeted by specialist commercial installers with deeper compliance, design, and aftersales infrastructure.
Real-world examples
To make this concrete, consider three recent profiles from our installed fleet:
- 300 kW rooftop install on a Tier-1 automotive supplier in the West Midlands. Annual electricity demand 1.4 GWh against £140k+ quarterly bills. 92% self-consumption, 4.8-year payback, second-phase 200 kW battery contract within 18 months.
- 120 kW roof install on a multi-academy trust secondary school in the East Midlands. 100% PSDS grant funded after Low Carbon Skills Fund feasibility. Live monitoring dashboard integrated into curriculum. Trust scaled the model to 5 further sites within 24 months.
- 650 kW PPA install on a logistics distribution centre in the South East. 12,000 sqm regional distribution centre. Zero capital, fixed 11p/kWh energy rate for 20 years (vs 22p grid). 130 tonnes/year carbon reduction reportable in ESG annual report from year one.
Practical guidance
For UK commercial decision-makers acting on the analysis above, three practical steps de-risk the decision. First, start with a proper desk-based feasibility study from half-hourly meter data — sizing systems to actual demand rather than to roof capacity is the single biggest determinant of project ROI. Second, engage a commercial-only specialist installer rather than a generalist running domestic work as their core business — the gap in compliance and design quality is wider than the headline price difference suggests. Third, map the funding stack early — combining AIA, capital grants where applicable, and the right financing route can improve project IRR by 4–6 percentage points.
Cross-references
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The DNO Connection Process for Commercial Solar: G98, G99 and Beyond
Every grid-connected commercial solar installation in the UK requires notification or approval from the Distribution Network Operator (DNO). The specific process depends on the system size and local grid conditions. Understanding the process — and starting it early — is critical to keeping your commercial solar project on schedule.
G98: Under 50kW — Notification Only
Systems under 50kW on a single-phase connection (or under 50kW per phase on three-phase) use the G98 notification process. The installer submits a G98 notification form to the DNO at least 28 days before commissioning. The DNO acknowledges but does not approve — there is no waiting period for approval, no queue and no risk of refusal for G98 systems in normal grid conditions. G98 is simple, fast and applies to the majority of small commercial solar installations (SMEs, small agricultural buildings, retail units). Our team submits G98 notifications as part of the standard installation process.
G99: 50kW-1MW — Active Approval Required
Systems above 50kW require a G99 application — an active approval process where the DNO assesses the system's impact on the local network before granting connection approval. G99 applications must include a full technical specification of the proposed installation (system design, protection relay settings, export control arrangements). Processing times vary by DNO and network congestion: 6-10 weeks in unconstrained areas (NGED Midlands, parts of NPg); 12-26 weeks in congested areas (UKPN South East, parts of SSEN South West). Our G99 application team has experience with all UK DNOs and can advise on current processing times for your specific location.
Can the DNO refuse a G99 connection application?
DNOs cannot refuse a connection outright — they have a legal duty to offer connection terms under the Electricity Act 1989. However, they can impose conditions on the connection: limited export (capping how much electricity you can export to the grid), export curtailment (requiring the system to reduce output at times of grid stress), protection relay settings requirements, or reinforcement contributions (where the local network requires upgrading to accommodate the new generation). We can advise on the typical conditions applied by each DNO for systems of different sizes in different grid areas.
What happens between G99 approval and commissioning?
After G99 approval is granted, the DNO issues a technical acceptance document specifying the approved connection terms (export limit, protection relay settings, metering requirements). The installer must commission the system in accordance with these terms. Our commissioning team configures all protection relay settings to match the DNO approval, completes commissioning tests, and notifies the DNO on the date of commissioning. The DNO may carry out a commissioning inspection for larger systems (typically above 250kW). Only after commissioning can the system be connected to the grid and generation begin.
Managing Your DNO Application: Our Service
Our G99 application service covers all UK DNOs: NGED (East and West Midlands, East of England, Yorkshire), UKPN (London, South East, East of England), ENW (North West England), Northern Powergrid (Yorkshire, North East), SSEN (Southern England, South West, Scotland), SP Energy Networks (Central Scotland, Merseyside). We submit G99 applications, manage the technical correspondence with the DNO connections team, respond to additional information requests and track applications through to technical acceptance. Contact us to discuss the DNO connection strategy for your commercial solar project.
Early DNO engagement is the most important schedule management action for commercial solar projects over 50kW. Our G99 application service can submit an application within 5 working days of receiving basic system information. Contact us today to start your DNO application process and secure your queue position.
Do not wait to start your DNO application. Our G99 application team can submit within 5 working days. Contact us today to secure your queue position and keep your commercial solar project on schedule.
Our G99 application team covers all UK DNOs and can submit applications within 5 working days. Contact us today to start your DNO process.