The export rules in brief
Ofgem's rules require some electricity suppliers to pay small-scale generators for the power they send to the network. Ofgem's own name for the arrangement is the Smart Export Guarantee, and the rules cover solar installations up to a capacity of 5 MW, far above anything on a house (Ofgem). Any supplier with at least 150,000 domestic electricity customers at the end of the previous year must offer an export tariff and cannot opt out; smaller suppliers can choose to take part (Ofgem). The installation has to be in Great Britain and meet the eligibility criteria, which for a home in the borough means the conditions in the next section.
What a supplier offers is largely up to the supplier. Ofgem says each can choose the rate, the contract length and some other terms, with one fixed rule: the rate must always be above zero (Ofgem). This guide prints no pence-per-kWh figures, because rates move and a figure copied today would mislead a reader next spring. Compare the current offers yourself when the system is close to switching on, and treat any rate on a quote as a snapshot with a date on it.
What you need before you can sign up
GOV.UK sets out what you need. The installation and the installer must be certified through MCS or an equivalent scheme such as Flexi-Orb; you need a meter capable of half-hourly export readings, which would typically be a smart meter; and you cannot take an export tariff while receiving export payments under the old Feed-in Tariffs scheme (GOV.UK). If there is no smart meter in the house yet, GOV.UK's advice is to speak to your energy supplier about getting one fitted.
The certificate is the condition that catches people out, because it depends on a choice made months earlier. It is registered by the installer, so the export tariff rests on the firm you chose being genuinely certified for solar when it did the work. That is a reason to search the firm on the MCS installer search under the exact name on the quote before you sign, as checking a solar installer explains, and to keep the certificate safe once it arrives.
Choosing an export tariff
You are not tied to your current supplier. GOV.UK says the supplier that pays for your exports does not need to be the same as the supplier that provides your energy (GOV.UK), though each supplier's own terms decide what it will accept, so read them before applying. Tariffs can be fixed or variable, and because they change over time GOV.UK suggests checking regularly that you are still on a competitive one. You apply to the supplier directly, and Ofgem publishes a list of suppliers that offer export tariffs.
When you compare offers, look past the headline rate. Read how often the supplier pays and how, whether a variable rate can change at short notice, how long any fixed rate lasts, and what happens to the export tariff if you later move your electricity supply elsewhere. Those terms decide how well a tariff suits a household that plans to stay put for years.
A battery does not rule you out. GOV.UK says storage, such as a home battery, may be used to benefit from an export tariff where it can both import and export electricity, and that prospective suppliers can advise (GOV.UK). If a battery is part of the plan, ask each supplier how it treats exports from one before you choose; batteries covers sizing and prices.
How much a Wigan semi sends out: two layouts
Semis are the borough's commonest home: 45.6% of Wigan households live in one, against 31.5% across England (Census 2021). Depending on which way the house faces, a semi's roof may offer one good south slope or a pair of slopes facing east and west, so take the same 4 kW both ways. On a south-facing slope at 35° in central Wigan, PVGIS gives 3,708 kWh a year. Split as 2 kW east and 2 kW west, it gives 2,960 kWh, because in central Wigan east and west are almost level, at 737 and 743 kWh per kW (PVGIS 5.3, our arithmetic). Semis and terraces covers how to tell which slopes a house has.
Set those against what a household uses. Ofgem's typical figure for electricity is 2,500 kWh a year (Ofgem), so the south roof makes about 148% of that and the east-west split about 118%, by our arithmetic. That does not mean the whole of it is used at home. Spread evenly, 2,500 kWh comes to about 208 kWh a month, and real use is never that even; still, the gap is plain. In June the south roof makes about 460 kWh and the split 434 kWh, while in December they make 108 and 44 kWh.
| Layout | kWh a year | June | December | Against 2,500 kWh |
|---|---|---|---|---|
| 4 kW facing south | 3,708 | 460 | 108 | 148% |
| 2 kW east and 2 kW west | 2,960 | 434 | 44 | 118% |
| Typical use, spread evenly (Ofgem) | 2,500 | 208 | 208 | 100% |
Summer is when most of the export happens. The months when output runs well above a typical household's use are the months that matter most for an export tariff, which is why the estimate on a quote should say how much of the yearly figure it expects you to use at home, how much it expects to send out, and what it assumed about when you are in. An east-west split puts panels on both slopes, so one catches the morning and the other the afternoon; whether that changes how much you use yourself depends on your day, not on the roof. Other directions and other parts of the borough are on output across the borough.
After switch-on: getting the tariff started
Ofgem says payments for exported power are calculated from export meter readings (Ofgem), so the meter is what turns spare power into something a supplier can pay for. Once the system is commissioned, the order of jobs is roughly this: the installer registers the MCS certificate and sends the network notice; you make sure a meter is recording exports; then you apply to the supplier you have chosen, with the certificate to hand. Keep the installer's paperwork together, because a supplier may ask when the system was commissioned and by whom.
Panels are not new to the borough. DESNZ counted 3,701 solar PV installations of every size in Wigan at the end of 2015 and 6,529 at the end of 2025 (DESNZ), and some of the older systems may have been registered under the Feed-in Tariffs scheme, which paid for exports too. If you bought a house with panels already on the roof, check the papers that came with it before applying: GOV.UK says you cannot take an export tariff while export payments under the Feed-in Tariffs are still being made (GOV.UK).
One more thing can shape the figure. If the system has an export limit, set to keep it within what the network agreed, the cap applies to what can go out, and the estimate of exports on the quote should already allow for it. Electricity North West and your panels explains why a system may be limited and what to ask.
What the quote should say about exports
RECC tells buyers to get the performance estimate in writing, and says its members follow strict rules for how those estimates are calculated (RECC). For exports, ask for the yearly figure in kWh split between use at home and export, the assumption behind that split, the meter you will need, and confirmation that the installer will register the MCS certificate and send the network notice. If a quote turns the export into pounds, ask which rate it used and when it was checked, and be ready to compare that with the offers available when you switch on.
Then test the yearly figure on the quote checker, which uses the same PVGIS figures for 12 places in the borough, and the price against the North West means on the costs page. A tariff can be changed later with a few emails; an inflated estimate or an uncertified installer cannot. If the figures do not add up, ask the installer to show its working before you sign rather than after.