It’s that time of year again, when the frost has settled in, the scarves are wrapped tight, and we’re all frantically buying last minute gifts in time for the big day! Energy usage is the last thing people want to think about during Christmas, but it’s also the time of year when energy is most important. The winter months see much higher energy usage across the UK with the biggest peak on the 25th of December itself. As our energy system transforms into a smart, connected ecosystem where demand has just as big a part to play as generation, how we control our energy usage around Christmas is going to become more and more important.
There are a few major factors that impact energy usage at Christmas. With the whole family around, the baseload is usually much higher – that’s things like lights, TVs, computers and other relatively low-power devices. On top of this, cooking uses a massive amount of energy. It may take a lot of work to get the turkey into the oven, but once it’s in there, the amount of heat it takes to cook the whole meal requires far more energy than on a normal day – whether that’s gas or electricity. This is all before you consider heating, which is usually the largest source of energy consumption in a home.
Historically most of this consumption has been from gas. The majority of UK homes still use gas or oil boilers for their heating, while around half use gas hobs for cooking (and 30% use gas ovens). As a rule of thumb, heat is always the biggest draw of power in a home (the only exceptions being where there are other high-power devices such as EV chargers installed). Therefore the extra electricity load, while still significant, has been dwarfed by gas and oil. However housing across the UK is becoming increasingly dependent on electricity in place of fossil fuels. This is great – electricity consumption has zero emissions at point of use, significantly reducing carbon emissions from UK houses. However, it comes with a host of new challenges.
Christmas goes all electric
Gas and oil are very easy to store and use when needed. Electricity, however, doesn’t hang around – it needs to be used when it’s generated. It can be stored in batteries but this isn’t always a very efficient solution, and there aren’t enough batteries connected to the UK’s grid to store all the electricity we need. In a world where our electricity comes from gas and oil generators, when the UK needs more electricity to support demand, we turn our fossil fuel generators up to increase generation. However the UK’s electricity supply is becoming less and less reliant on fossil fuels. The last coal power plant in the UK shut down in October 2024, and 2024 is also the first year where renewable sources have generated more of the UK’s electricity than fossil fuels. Renewable generation is dependent on natural conditions, such as wind speed or sunlight, meaning we can’t just shift when we generate our electricity.
Electricity suppliers use forecast profiles to estimate how much electricity each home or business will use across the day. For a normal household this profile features two periods of high usage at the start and end of the day, corresponding to when people wake up and return from work, with a big peak in the evening when people are cooking dinner. At Christmas this profile is turned on its head! Lunch becomes the biggest meal of the day, and even that’s usually served later than a standard lunch, meaning there is one continuous peak through the morning and early afternoon. This would be really handy, as this coincides with usual periods of high solar generation. But the sun isn’t usually particularly high in the sky in the middle of winter!
How to save Christmas
This all results in a massive amount of demand in the middle of the day at a time when the grid can’t handle it. In order to ensure the power keeps flowing and we don’t end up with undercooked roasties, we need to make sure that every house in the country isn’t using electricity at the same time of day. It’d be even better if we could shift electricity away from the middle of the day to overnight, when there’s usually more generation coming from wind turbines.
Lots of the electricity demand on Christmas day can’t be easily shifted. After all, who wants to eat the turkey at nine in the morning?
Luckily, some of our biggest sources of electricity consumption at Christmas are flexible. Many of the highest power devices in the home are also the easiest to shift in time – home batteries, EV chargers, electric heaters and heat pumps.
With heat, it’s obviously important that gran isn’t shivering in the corner whilst presents are being opened. But that doesn’t mean that your heating device has to be running at max power throughout the day. Most homes, especially modern ones, are really good at holding heat. Ensuring the house is warm in the morning can mean it only needs a few small top ups of heat throughout the day. This is helped by the larger number of people usually in the house for Christmas, as well as the heat emitted when cooking Christmas dinner! Shifting electric heating to periods of high renewable generation helps reduce peak demand, utilise cleaner electricity and reduce energy costs for householders.
The flexibility of heat and other devices, especially during the winter, is essential in keeping our electricity supply secure. Transitioning away from fossil fuels isn’t a choice – if we want to keep enjoying white Christmases, we need to transition to a clean energy system. But the unpredictability of renewable generation comes with its own challenges. Smart operation of high power devices such as heat pumps enables our homes to coordinate power usage with power generation, ensuring that Christmas day is powered by cleaner, cheaper electricity.
