Permission Slips for the Roof and Wall: Understanding DNO Consent for Domestic Renewables in 2026
The connection question comes before the commissioning date
For many homeowners, a renewables project begins with a roof survey and a shading analysis. The distribution network operator, or DNO, tends to enter the conversation much later, often when the installer is ready to book a commissioning date. That sequencing is understandable, but it is not always wise. In 2026, with more homes adding solar, batteries, heat pumps and electric vehicle charging to the same supply, the local network is being asked to absorb more distributed activity than before. DNO consent is not a formality that can be assumed; it is a technical and administrative process with its own thresholds, timelines and failure points.
The DNO owns and operates the local electricity distribution network. It is not the planning authority, and it does not replace building regulations or MCS certification. Its interest is narrower but important: whether the proposed equipment can connect safely, whether it can export without causing voltage or frequency problems, and whether the local network has the capacity to accommodate the change. For a domestic project, that usually means one of two routes: G98 notification or G99 application.
G98 and G99: two doors into the same network
Engineering Recommendation G98 applies to small-scale embedded generation up to 16 amps per phase. On a single-phase domestic supply, that is roughly 3.68 kW; on a three-phase supply, the threshold is higher because the limit is applied per phase. G98 is a notification process, not a prior approval process. The installer commissions the system and notifies the DNO within 28 days, and the DNO has a window in which to object or require changes. That does not mean the homeowner can ignore the DNO beforehand. A responsible installer will check the existing supply and the proposed inverter rating before work begins, because a G98 notification that later attracts an objection is a poor outcome for everyone.
G99 is the route for larger systems, for multiple generating units, and for installations that fall outside the G98 threshold. It is an application-led process: the DNO receives the proposal, assesses it against the network, and may issue a connection offer with conditions. Those conditions can include export limitation, a revised protection setting, or a requirement for further equipment. The installation should not proceed on the assumption that approval will be granted. The offer is the point at which the project has a defensible connection position.
Battery storage complicates the picture. A battery that can export is treated as generation, so its inverter rating and export behaviour matter. A battery configured not to export may still need to be declared, and the export limitation itself must be engineered and certified rather than left as a setting in an app. Installers should not assume that a zero-export battery is invisible to the DNO. Heat pumps sit on the other side of the meter: they are loads rather than generators, so they usually fall outside G98 and G99. However, a larger heat pump can push a single-phase supply close to its fuse limit, particularly where an electric shower, immersion heater or EV charger is already present. DNOs may ask for a load assessment, and some will require an application where the increase is material.
Export limitation is a design decision, not a sticker
When a DNO offers a constrained connection, export limitation is often the compromise. The system is allowed to connect, but it must not export above an agreed level, or must not export at all. This is usually managed under G100, the engineering recommendation for export limitation schemes. The important point for homeowners is that export limitation is not a box-ticking exercise. It affects inverter selection, control settings, commissioning tests and future maintenance. A system that is set to zero export but later has that setting changed without DNO agreement is no longer the system that was approved.
Export limitation can also affect the economics of a solar and battery project. If the DNO permits only a small export capacity, the case for the system may depend more heavily on self-consumption than on export payments. That is not a reason to abandon the project, but it is a reason to model it honestly before signing a contract. The DNO's constraint is part of the system design, not an afterthought.
Timelines, assumptions and the points where projects stall
The most common installer assumption is that G98 notification can be handled entirely after commissioning. In many straightforward domestic solar installations, that is how the process works. It becomes a problem when the system is larger than the installer assumed, when the property already has generation, or when the DNO's records do not match the supply capacity on site. A second common assumption is that a battery will never export. A third is that a heat pump is simply a load and therefore needs no discussion. Each assumption can be reasonable in isolation; each can also cause a project to stall at the connection stage.
G99 timelines vary by DNO and by the complexity of the local network. Some applications are straightforward; others require reinforcement studies or queuing behind other projects. Homeowners should ask the installer to confirm in writing which route applies, what information has been submitted, and what conditions the DNO has attached. It is also sensible to keep the DNO correspondence with the project file, because connection conditions can affect warranty, commissioning and future upgrades.
The practical lesson for 2026 is that grid connection should be checked early, before equipment is ordered and before installation dates are promised. A short delay at the application stage is usually less expensive than a system that cannot be commissioned as designed. The DNO is not an obstacle to domestic renewables; it is part of the project's technical context. Treating it that way makes the rest of the installation more predictable.
