Every solar or battery system that runs in parallel with the grid needs the network operator’s approval before it energises. For a commercial system, that approval — not the installation itself — is often the item that sets the project timeline. Here is how it works and how we handle it.
Who the DNO is
Your Distribution Network Operator owns and runs the local electricity network your site connects to. There are six DNO groups covering Great Britain’s regions — including National Grid Electricity Distribution, UK Power Networks, Northern Powergrid, SP Energy Networks, SSEN and Electricity North West. You don’t choose your DNO; it comes with your location.
G98 and G99 — the two connection routes
- G98 covers micro-generation up to 3.68kW per phase (about 11kW on a three-phase supply). These systems can be connected first and notified to the DNO within 28 days. Almost no commercial system is this small.
- G99 covers everything larger — which means effectively every commercial rooftop, ground-mount and battery project. A G99 application must be submitted and approved before the system is connected. The DNO studies whether the local network can accept the generation, and either approves it, offers a modified connection, or quotes for network reinforcement.
- G100 is the standard for export limitation. Where the network can’t accept full export, an approved limitation scheme caps what the site sends out while leaving on-site use untouched.
What the application involves
A G99 application describes the generator and inverters (manufacturer type-test data), the site’s existing supply, protection settings and single-line diagrams. Larger schemes may need witness testing at commissioning, where the DNO checks the protection systems behave as declared. Getting the paperwork right first time is the single biggest factor in a fast approval.
How it affects your project timeline
DNO response times vary with the size of the connection and the state of the local network — from weeks for a straightforward rooftop to months where studies or reinforcement quotes are involved. This is why Novalux submits the DNO application at the start of the project, in parallel with design and procurement, rather than after the panels are ordered. By the time the system is ready to install, the connection is ready to accept it.
Export limits are not deal-breakers
A common worry is the DNO limiting export to zero or near-zero. In practice this rarely damages the business case: commercial solar earns most of its return by displacing electricity you would otherwise buy at retail rates, not by exporting at wholesale rates (what actually drives payback). Where an export limit would otherwise waste generation, a battery stores it for the expensive hours instead — and Nova AI decides every half hour whether that stored energy is worth more used on site or sold.
Handled for you
Novalux manages the full DNO process on every project — application, protection settings, any export-limitation scheme and witness testing — as part of the installation service, alongside planning consents. It’s one of the reasons our order-to-install timelines hold: the grid paperwork starts on day one. See it delivered across our completed projects, or request a Quick Quote to start yours.