Octopus Agile explained

Agile prices electricity in half-hourly slots that follow the wholesale market. Rates are published the afternoon before, so you always know tomorrow’s prices, and they can swing from very cheap to very expensive within the same day.

It rewards a household that can move consumption. It punishes one that cannot, and the size of both effects is knowable in advance from your own smart meter data, which is the honest way to decide.

How the pricing works

Every half hour has its own price, derived from day-ahead wholesale prices. Per the tariff’s own page, the next day’s rates are published between 4pm and 8pm, usually nearer 4pm, and a cap the supplier calls Price Cap Protect guarantees you never pay more than 100p per kilowatt hour in any slot.

Two features matter more than the average rate:

The spread is large. The gap between the cheapest and dearest slot on a given day is usually substantial, and occasionally enormous: the same day can contain slots priced in single digits and slots several times the standard capped rate of 26.11p. That spread is the opportunity.

Prices can go negative. When the grid has more generation than demand, typically on windy nights or bright, breezy afternoons, the tariff’s Plunge Pricing passes negative wholesale prices through: you are paid to consume, and the supplier alerts you when it happens.

Who benefits

Anyone with a battery. Storage turns the spread into money directly: charge in the cheap slots, discharge during the expensive ones. This is the clearest case and it works whether or not you have solar, on the same arbitrage arithmetic as any spread, except that Agile’s spread moves daily and occasionally pays you to fill the battery at all.

Anyone with big shiftable loads. An electric car, an immersion heater, a dishwasher and washing machine on timers. The more of your consumption you can move, the better it works.

Anyone willing to pay attention. Prices are published daily. Households that check and plan around them, or automate the response through a scheduled battery and charger, do noticeably better than those that do not. Automation matters: the tariff’s winners are mostly systems, not people with alarms set for 4pm.

Who does not

A household with a flat consumption profile, no storage and no flexibility is exposed to peak prices without any way to avoid them. Early evening on a cold, still day is precisely when Agile is at its most expensive, and it is also when an inflexible household uses most. On a bad week that combination costs real money, and there is no mechanism to recover it.

If your evening looks the same every night and nothing can move, a fixed tariff is the more sensible choice, and that is a legitimate answer rather than a failure of nerve.

The interaction with solar

This is the part specific to a generating household, and it is not entirely favourable.

Your generation peaks in the middle of the day. Wholesale prices often dip in the middle of the day, precisely because everyone else’s solar is generating too. So the hours when you have most to export can be the hours when export is worth least, the same correlation that complicates tracking export rates generally.

The corollary is that your generation reduces your imports during hours that were already cheap, which is worth less than reducing imports during the evening peak.

None of this makes Agile wrong for a solar household. It means the benefit comes from the evening rather than from the middle of the day, which is another way of saying it comes from having a battery that can carry midday energy into the expensive slots. A plain solar household is usually better matched by a flat export rate or the battery-oriented fixed-period tariff.

Managing the risk

Two things worth knowing before switching:

The cap is real but high. The 100p per kilowatt hour ceiling stops the tail risk, but it sits nearly four times the standard capped rate. A cold, still winter evening can be genuinely expensive; the cap makes it bounded, not cheap.

Switching away takes time. If prices move against you, you are not trapped, but you are not out tomorrow either. Treat it as a commitment of some months rather than a week-by-week choice, and keep the first month’s data to check the theory against the bill.

Checking whether it suits you

Do this with your own data rather than with an average:

1. Get your half-hourly consumption for a representative month.
2. Obtain the corresponding half-hourly Agile prices for the same period; they are published and archived.
3. Multiply each half hour of consumption by that half hour’s price and total it.
4. Compare against the same consumption at your current flat rate.

That gives you the honest answer for your household as it behaves now, before any changes. Then repeat it assuming you shift your most flexible loads into the cheapest few hours, which gives you the answer for the household you would become.

The gap between those two numbers is the amount of effort the tariff is asking of you, expressed in pounds, and it is the only figure that should decide the switch. For many households the first number is slightly worse than the flat rate and the second is much better: Agile is a tariff you join for the household you are willing to run, not the one you have.

It is one of several shapes

The same supplier offers a battery-oriented tariff with fixed periods and an EV-oriented one with a cheap overnight window at 8p per kilowatt hour. Those are more predictable and less demanding. Agile pays more to households that engage with it and less to those that do not, which is the whole design, and the reason the honest self-assessment above belongs before the switch rather than after the first surprising bill.