How the Smart Export Guarantee works

Every unit of solar you don't use yourself gets sold back to the grid, and the price you get for it varies by more than most people expect. The same exported kWh can earn 3p from one supplier or 20p from another. Over a year that gap is worth hundreds of pounds, so the tariff you pick matters almost as much as the panels. Here's how the Smart Export Guarantee works and how to get paid more for what you send out.

What the SEG actually is

The Smart Export Guarantee (SEG) launched on 1 January 2020. It requires every licensed electricity supplier with 150,000 or more domestic customers to offer at least one tariff that pays you per kWh you export to the grid. It replaced the old Feed-in Tariff, which closed to new applicants in March 2019 and paid for generation rather than export.

To qualify you need an MCS-certified install and an export-capable smart meter, so the supplier can measure what you actually send back rather than estimate it. You don't legally have to buy your electricity from the company that pays your SEG, but, as you'll see, the best rates usually come with strings attached.

How much the rates vary

Suppliers set their own SEG rate, and the spread is wide. The floor sits around 3p to 4p per kWh from the suppliers offering the bare legal minimum. The best widely-available flat rates reach about 20p, the most popular sit near 15p, and a cluster pay around 12p. Most of the strong rates require you to take your import electricity from the same supplier too, plus their smart meter.

On a typical home without a battery, you might export 50% to 70% of what you generate. A 4 kWp system producing roughly 3,600 kWh a year could send back around 2,000 kWh. At 5p that's £100 a year; at 15p it's £300; at 20p it's £400. Switching from a poor SEG tariff to a good one can be worth £200 to £300 a year on its own, with no change to your panels.

Fixed versus agile export tariffs

Most SEG deals are flat-rate: a single price per kWh, all day. A few are variable or "agile", paying the half-hourly wholesale-linked price instead. Agile can spike well above 20p during the evening peak, which sounds great, but solar exports most at midday when wholesale prices are low. Agile export mainly rewards people who can choose when to export, for example by discharging a battery to the grid at the evening peak. For straight solar export, a strong fixed rate is usually the simpler win.

The catch worth remembering

Export is the consolation prize, not the main event. Every kWh you use yourself avoids buying at the import rate, around 25p, which beats any export rate going. So SEG matters most for the surplus you genuinely can't use. The order of priority is: use it live, then store it (see do I need a battery), then export what's left for the best rate you can find. Don't chase a high export rate at the expense of self-consumption.

How to choose a SEG tariff

• Compare the headline p/kWh, but check whether the rate requires you to buy import from the same supplier, and whether their import price is competitive.
• Confirm you have, or can get, an export-capable smart meter. Without it you can't be paid.
• Check for exit fees or fixed terms, since the best SEG rates move around and you may want to switch.
• If you have a battery or plan one, look at whether an agile export tariff plus evening discharge beats a fixed rate for you.

Worth solar in the first place is a separate question, covered in is solar worth it. Once you know it is, the SEG tariff is one of the cheapest levers you have on the return.

Do you have to switch suppliers?

Not for the SEG itself, but the economics usually pull you there. The strongest export rates are loyalty tariffs reserved for customers who also buy their import electricity from the same supplier. So the real comparison isn't the export rate alone, it's the combined cost of import plus the value of export. A supplier paying 20p to export but charging 3p more per imported unit can leave you worse off than a 15p export deal on cheaper import, depending on how much you buy versus sell.

That balance shifts with your self-consumption. A home that uses most of its solar and imports little leans toward the best export rate. A home that exports a lot but also imports heavily should weigh the import price just as carefully.

Will the rates hold up?

The SEG sets no minimum price, so rates aren't guaranteed. They move with wholesale energy prices and supplier competition. They've broadly risen as more suppliers chase solar customers, but there's no promise that today's 20p deal lasts. Treat the export rate as something to review every year or two, like any tariff, rather than a fixed feature of owning panels. One thing that doesn't change is the basic right to be paid: any large supplier must offer a SEG tariff, so you'll always have somewhere to sell your surplus, even if you shop around for the best price.