Posted: 21 December 2015

Why the TV guide is vital for National Grid’s forecasting team

National Grid, Christmas, energy, Boxing day, electricity, forecast
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The TV listings guide is a vital piece of equipment when it came to predicting spikes in demand.

You’d be forgiven for thinking Christmas Day would bring one of the highest demands for electricity of the year. 

But no. Despite all the twinkling lights, roasting hot ovens and TV watching, Christmas Day is likely to have one of the LOWEST electricity demands of the winter.

National Grid’s Forecasting Manager Jeremy Caplin explained: “Energy usage for Christmas Day is very different to the rest of the year.

“As factories, shops and offices close their doors, demand drops significantly and Christmas Day follows a different pattern to the one we see on a typical winter’s day (see graph below).

“Demand rises steadily as people wake up and begin turning on their ovens to cook their turkeys, and reaches a peak around lunchtime.”

Forecasters

Jeremy is part of an expert team which balances supply and demand on a second-by-second basis and predicts how much energy will be needed.

Every year National Grid’s team of forecasters looks at a range of past trends, behavioural data and detailed updates from the Met Office to forecast just how much electricity will be needed over the Christmas period.

Weather conditions, temperature and the day of the week on which Christmas falls can all make a difference to the forecast.

This year forecasters are predicting a lunchtime peak of around of 35,410 MW enough to light up 3.5 billion Christmas Trees – compared to a typical busy teatime peak of 50,000 MW. The picture will be updated several times a day from now until December 25.

“Last year Christmas Day had the lowest demand of the whole winter, which was 36,357 MW – though that’s still enough energy to light up 3.6 billion Christmas trees,” said Jeremy.

“Traditionally Boxing Day was always quieter – but in recent years behaviour has changed and it is now a popular sales day with supermarkets and shopping centres opening their doors and increasing demand for energy.

“In 2014, the Boxing Day demand was higher than Christmas Day and we expect to see the same again this year.”

TV pick-up

And Jeremy revealed that the TV listings guide was a vital piece of equipment when it came to predicting spikes in demand. At the end of the most popular shows there’s what’s called a ‘TV pick-up’.

Jeremy explained: “It’s important for us to determine which will be the most watched programmes as demand for electricity increases when these shows come to an end and people begin turning lights on, boiling kettles or even opening the fridge for a festive tipple.”

Last year the show with the biggest TV pick up was EastEnders.

The end of the show coincided with a commercial break in Downton Abbey and saw a pickup of 320 MW – the equivalent amount of energy needed to light 32 million Christmas trees.

The biggest Christmas Day pick-up in recent times followed an episode of Only Fools and Horses in 1996 with a pick-up of 1,340 MW – enough electricity to bake 30 million mince pies.

This year the team is predicting the last ever Downton Abbey will provide the biggest pick-up of 400 MW, followed by Coronation Street and Call the Midwife which are due to finish at the same time.

Christmas Day and Winter Peak

Christmas Day follows a different pattern to the one we see on a typical winter’s day.

Gas innovation in full flow
“In 2014, the Boxing Day demand was higher than Christmas Day and we expect to see the same again this year.”

Jeremy Caplin, Forecasting Manager, National Grid.