Every solar system in Luton ends with the same step: a form to the company that owns the cables in your street. Most homeowners never see it, because the installer files it, but it decides how big a system can be, when work can start and whether anything has to change at the meter first. This guide walks through that process from survey to switch-on for a Luton home, and gives the plain answer on what panels and batteries do in a power cut. For the roof side, the town’s planning rules and its 2040 net zero pledge, see our page on solar panels in Luton.
One distinction first. The network operator owns the wires and substations. It is not your energy supplier, and changing supplier does not change it.
Who owns the wires in Luton
UK Power Networks. Its own licence-boundary data places central Luton inside its Eastern Power Networks area, and on the National Energy System Operator’s boundaries the nearest other licence area is about 18.6 km from the town-centre point. UKPN’s history page records that its Eastern predecessor managed the cables and lines in most of Bedfordshire. If you want to confirm the operator for your own address, UKPN’s area checker does it by postcode.
At the survey: what decides the paperwork
The surveyor is not only measuring the roof. Three electrical details shape the connection:
- System size. The inverter’s rating, and whether a battery adds to it, decides which form applies.
- The supply. Most UK homes lack a three-phase supply, so the G98 line below is measured on a single phase, and the main fuse rating matters if an EV charger is also on the list.
- Export. How much the system could push onto the network at once, which can be capped by a setting.
At the 2021 Census, 40.3% of Luton’s households lived in semi-detached houses and 20.5% in purpose-built flats. On a semi the survey usually leads straight to a design. In a block of flats, a shared supply and a shared roof mean the freeholder’s consent comes before the network question.
The small-system route: G98
Under the Energy Networks Association’s G98 standard, type-tested equipment up to and including 16 A per phase, 3.68 kW on a single-phase supply, is notified to UK Power Networks before commissioning or no later than 28 days after it. UKPN’s Smart Connect service handles these forms for solar PV and battery storage, and only approved installers can use it. You do not fill anything in.
The larger-system route: G99 and the 5 kW line
Above 16 A per phase, a G99 application has to be approved before the work starts. The line is lower than people expect: a 4 kW inverter runs at 17.39 A, just over it, so a typical solar-and-battery system on a Luton semi can easily land on the G99 side.
UKPN says it automatically approves an application where the installation’s maximum export, after any export limitation scheme, is under 5 kW. An export limit is a setting that caps what the system sends to the network, even if the inverter could deliver more to the house. It is one way a larger system stays inside the automatic-approval band. Our explainer on solar battery storage covers how a battery changes what is exported.
If the supply needs upgrading
Sometimes UKPN finds that a supply is not sufficient for the additional load and has to upgrade it first. If no upgrade is needed, UKPN says there is nothing for you to pay it. If one is, it says the cost and timing vary from project to project. Either way, the installer deals with UKPN on your behalf, and a good quote says which route it expects.
When the grid goes down
This is the part most often misunderstood. A standard grid-connected solar inverter switches off when the grid does. That is deliberate: it stops your system feeding power into cables that engineers may be working on. A battery on a standard design behaves the same way, so a full battery will not, on its own, keep the lights on.
Backup can be designed in, for selected circuits or the whole house. It changes the specification, the wiring and usually the price. Our guide to battery storage without solar panels explains how backup fits into a design, and our page on battery storage in Luton covers storage for the town’s homes.
How often would it matter? Ofgem’s 2024/25 figures for Eastern Power Networks show about 44.6 supply interruptions per 100 customers and about 32.5 minutes lost per customer over the year, planned and unplanned together. Those are averages across a licence area that runs well beyond Bedfordshire, as reported before Ofgem’s final assessment, not a forecast for your street. Use them to decide calmly whether backup is worth paying for.
After switch-on: export payments
Once the system is commissioned, the MCS certificate and electrical certification arrive after the installation is registered. A Smart Export Guarantee tariff needs that MCS certificate and a meter able to take half-hourly export readings. Rates are set by each supplier and must be above zero under Ofgem’s rules; they change at short notice, which is why we never print one. We are MCS-certified for solar PV and battery storage, held via NAPIT (member 73495).
For the county view, including how UKPN covers most of Bedfordshire, see solar panels in Bedfordshire. When you would like a survey that covers the connection as well as the roof, use our contact page.
Sources: UK Power Networks, Licence Boundaries open dataset, Our history, Areas we cover, Smart Connect, and Solar panels and energy storage: cost, time and what’s involved; NESO, GIS boundaries for GB DNO licence areas (May 2024); Energy Networks Association, EREC G98 Issue 2 (10 March 2025); Ofgem, RIIO-2 Electricity Distribution annual report 2024 to 2025 and supplementary datafile (reliability); Ofgem, Smart Export Guarantee; ONS Census 2021, TS044 Accommodation type via Nomis (Luton).