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Sign up for advance warnings so you can consider reducing electricity consumption during potential Triad periods.

National Grid uses Triads, three half-hour periods of peak demand in the winter, to determine its annual charges for transmission. If your business is a heavy power user, sign up for our free Triad alerts so you can reduce consumption during these peak times to minimise future transmission costs.

What are Triads?

Triads are three half-hour, peak periods during the winter that see the highest demand for electricity. “Tri” refers to the three periods, while “AD” stands for average demand.

Triads can be on any day from 1 November to the end of February, but they must be at least 10 days apart so that they don’t fall on consecutive days.

Triads usually occur between 5.00pm and 6.00pm because that’s when both industrial and domestic consumption tends to peak. But they do sometimes occur outside this window.

We can’t predict when Triads will fall with 100% certainty, mainly because they’re only determined after the event. Every year in March, National Grid reviews the season’s data to find the three peaks in demand with at least 10 days between each one.

Is TNUoS the same as Triads?

No, although “TNUoS” and “Triads” are sometimes used interchangeably. TNUoS is short for Transmission Network Use of System – the charge that covers the cost of installing and maintaining the electricity transmission system. Triads are used to determine TNUoS charges for businesses with half-hourly meters.

The aim of the Triad system is to incentivise industry to help smooth out peaks in energy demand during the winter, especially in cold snaps.

Why are Triads so important for major power users?

If you get half-hourly bills, your total TNUoS charge for the coming financial year is calculated based on your average consumption in the three half-hour Triad periods.

So if you’re a heavy user of electricity, optimising these costs can make a big difference to your annual spend – the more you reduce your energy usage during Triads, the lower your TNUoS payments will be for the whole of the next year.

But Triads won’t be so significant for much longer. Ofgem is currently reviewing network charges in its Targeted Charging Review (TCR), which is set to reduce the Triad element of your charges. Find out more about TCR and changes to future electricity network charges.

How do I reduce Triad-related charges?

You can sign up for our Triad warning email alerts so you’ll know in advance when Triads are likely to occur. You can then consider ways to minimise your energy consumption from the grid at those times.

If you’re a larger business with the ability to reduce demand or use on-site generation, you might like to consider a Triad management service. SSE Virtual Power Plant includes an automated Triad alert and dispatch service that helps you minimise Triad-related costs. It can also help you make the most of your flexibility, giving you access to new revenue streams.

How many Triad warnings might I get?

There could be around 20-30 potential Triad warnings in winter (November to February). However, since Triads are assessed after the event, it’s impossible to know in advance which half-hour will be a Triad. That’s why it’s important to sign up for our Triad warning service and have an energy efficiency strategy in place.

Can I make money from Triads?

You can make money from Triads if you can generate power and are able to supply excess electricity to the National Grid during Triad periods. SSE Virtual Power Plant can help you earn revenue from your existing assets.

Sign up for Triad warnings

Triads are determined by National Grid ESO so we can’t guarantee to give exact timings, but we’ll do our best to provide well-informed warnings.