Our early outlook on winter margins in 2021/22

Every year we share our summer and winter outlooks with the energy industry, outlining anticipated levels of supply and demand, and some of the challenges we might see in operating the electricity system.

This year, to help industry’s and the market’s preparations for the winter, we’re publishing an early outlook for this key period – with a focus on the margins we expect to be operating the system with.

Read our Winter Outlook early view of margins


Reflecting on last winter

Over last winter we saw some complex and challenging operating conditions leading to tight margins on occasions.

As detailed in our Winter Review, we used the tools at our disposal to balance the system and keep Britain’s electricity supply secure – including some tools, like the electricity margin notice (EMN), that we hadn’t used for a number of years.

We may see some tight margins again this winter, but we’re confident there’ll be enough electricity to keep Britain’s lights on

The tight margins and the actions we took were driven by a range of factors.

Wind patterns varied significantly, with periods of record-high output followed by spells of unusually low wind. Several transitions in and out of national and regional covid-19 lockdowns also had a changing impact on national demand.

However the main driver behind last winter’s lower margins was coal and combined cycle gas turbine (CCGT) plants being less available than had been notified at the time of our Winter Outlook report in October – creating a shortfall in available supply compared with expected levels. Unplanned interconnector outages were also a factor.

Everything you need to know about electricity system margins


Looking ahead to this winter

In giving industry an early view of our expected margin levels, we hope to support the electricity market in planning for this winter.

Our provisional view indicates that system margins could be similar or slightly lower than last winter, though they remain well within the government’s reliability standard for safely and securely operating the system.

So while we may see some tight margins again this winter – and we may need to use routine tools such as EMNs to help balance supply and demand – we’re confident there’ll be enough electricity to keep Britain’s lights on.

We'll be following up our early view with our more detailed operational forecast in the full Winter Outlook, due to be published in October 2021.