For the first time ever households will be paid to use less electricity this evening. Shehab Khan has the latest.
Some households will be paid to cut back their energy use again on Tuesday evening amid concerns electricity supply margins may be "tighter than normal".
For the second time, the National Grid will activate its Demand Flexibility Service, after it was activated on Monday evening for the first ever time.
The scheme entitles some households with smart meters to discounts if they cut their use of electricity.
Launched last November, the Demand Flexibility Service allows the Grid to access additional flexibility when national demand is at its highest.
Why might the UK's electricity supply tighten?
The current cold weather means more people are heating their homes, which increases demand for energy. However, a lack of wind has reduced the amount of renewable energy available.
National Grid said that as well as activating the Demand Flexibility Service, it has ordered three UK coal plants to begin warming up in case they are needed to boost the energy supply.
The Grid added that its announcement should not be interpreted as a sign that electricity supplies are at risk and said “people should not be worried”.
When will the energy discount scheme run this week?
The scheme first went live on Monday, 23 January, between the hours of 5pm and 6pm.
The National Grid said it could also pay households to slash their electricity use between 4.30pm and 6pm on Tuesday 24 January.
It said that it was looking for bids from suppliers to help save up to 341 megawatts (MW) on Tuesday.
The plan could still be abandoned if conditions improve.
Who is eligible to save money via the scheme?
To be part of the scheme, you must have a smart meter and you must have signed up to the scheme through your supplier.
If you have signed up, your provider should have contacted you asking you if you want to take part in tonight's event.
The full list of energy suppliers taking part:
CUB (UK) Ltd
ENGIE Power Limited
Hugo Energy App
Labrador (via Perse Technology Ltd)
myenergyi (via Orange Power)
Power Rewaeds App (via Orange Power)
Shell Energy Retail
Zenobe Energy Limited
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How do I reduce my energy consumption during the aforementioned windows?
The National Grid advised households to run "power-hungry" appliances outside of the window of time it was asking them to reduce useage.
These appliances include:
Another option would be to reduce your energy usage (e.g. using a microwave instead of the oven) during the event window.
Will there be more opportunities to save money on energy with the scheme?
There are likely to be other live runs this year - Ofgem has granted approval for the scheme to run from November 3 2022 to March 31 2023.
How much can I save?
The National Grid previously said a typical household will be able to save approximately £100 over the five month duration of this service.
However, it is up to each electricity supplier how much and in what form this money is passed onto customers. The £100 figure is also only an approximate average.