Managing energy demand over lockdown: Q&A with Ben Young, National Grid Electricity System Operator (NGESO) Control Centre

1. What are the biggest challenges you have faced with keeping the lights on?

Many people often assume that with more of the population staying at home and using more domestic energy, overall demand would increase. But that’s not been the case. Over the past months, electricity demand has been significantly lower than usual, due to a large decrease in energy use from commercial and industrial consumers.

It’s the role of our control room to keep supply and demand for electricity in balance. The tools and processes our control room currently has in place to do this mean Great Britain’s system is one of the most reliable in the world. But to help us manage the unprecedented situation caused by the pandemic and the reduced demand for electricity, we’ve also been working with industry to explore additional options (more on this below).

2. How much has demand dropped since lockdown started?

There has been a large drop in demand since lockdown first began in March. We’ve been looking closely at demand behaviour and comparing that to demands in 2019. It’s not possible to make a direct comparison between 2020 and 2019 because the weather on a particular day would naturally push demand up or down. So we have corrected for the effect of the weather as far as we can and produced the following chart, which has been updated each day during lockdown.

This chart illustrates the key observations. Weekdays have a greater percentage reduction than weekends. This is because the lockdown had a much greater impact on industry and commerce and actually enhanced residential demand slightly. Overnight demands also have a smaller percentage reduction than the daytime hours for similar reasons.

There has also been a general trend of recovery since the low point just after Easter. This trend is not really a straight line but consists of a number of steps as different aspects of lockdown have been eased and different parts of the economy have made steps towards normality. We are mindful that this upward trend could be reversed if the activity of Covid-19 increases and requires levels of lockdown to be tightened.

3. Are you seeing less variation in supply/demand patterns – or more?

A typical daily demand curve comprises of a number of peaks and troughs throughout the day, as the consumption of electricity varies. Usually there is a peak shortly after 6:00am when people get out of bed, pop the kettle on, have a shower and get ready for work. With so many people furloughed or working from home, this morning pick up all but disappeared. But we're slowly seeing it start to return now. The same can be said for the early evening pick up, when people would usually be coming back from work and cooking dinner.

We’ve also seen some periods of incredibly low demand since lockdown began. For example, early morning – normally about 5:00-5:30am – and early afternoon.

4. Are you seeing non-domestic consumption start to pick up now?

Yes, we’ve seen some evidence of demands recovering towards 2019 levels over recent weeks as the chart above illustrates.

This has made prediction of electricity demands more challenging because there are two conflicting factors at work. The easing of lockdown for certain areas of the economy is allowing business to re-open and demand for electricity from these businesses has been increasing as a result. At the same time, there have been many announcements of redundancies and businesses closing, which reduces demand from those sources.

Considering these two opposing factors – and incorporating them into the electricity demand forecast – has been the challenge of this lockdown period for the Energy Forecasting Team.

5. What steps have you had to take to ensure supply doesn’t overwhelm demand?

We’ve put in place tools and processes for our control room to draw upon, and give them additional support over the summer period. For example we have put in place a new balancing service (Optional Downward Flexibility Management) which has allowed us to access service providers connected to the distribution system.  Measures such as these primarily focus on making sure that electricity supply on the transmission and distribution networks can be managed effectively. This allows our control room to maintain stability on the transmission network in any situation, including those currently beyond our forecasted summer scenarios.

6. How can businesses support this?

We have had a great response from industry on the flexibility and services we require to operate under low demand conditions and we want to continue to work collaboratively with all our customers and stakeholders.

As businesses return to normal with the easing of lockdown, and demand increases, they can rest assured that’ll we’ll continue to balance the grid.

7. Have you had a good uptake of your new Optional Downward Flexibility Management service?

Yes, 4.5GW of capacity signed up within the two months of the Optional Downward Flexibility Management (ODFM) service launching.

8. If so, what sorts of businesses are participating?

We have seen a large uptake from both wind and solar generators, as well as demand turn up from operational business sites. All accepted and rejected bids are published in our market information reports. As part of these reports, we also show the technology type of each unit. You can see more here.

9. Have you been able to model potential demand patterns going forward? If so, what sorts of information do you need to enable you do this (i.e. working closely alongside government decision makers, business forecasters etc.)?

It’s our standard process to produce a demand forecast all the way up to 13 weeks into the future. This is updated once per day and uses seasonal average weather.

As you can imagine, it has been a challenge to skilfully produce these long-range electricity demand forecasts while we have been in various stages of lockdown with substantially lower demand.

Our main approach has been to extrapolate the recent week of history into the future. We recognise that some things cannot be predicted. One of those things is the exact government response to Covid-19 (and infection rates) and the resulting public response to those measures. In light of that, we have found that it’s better to have a clear strategy for forecasting. Our forecasts beyond seven days ahead have an implicit assumption that the level of lockdown will stay the same as it did last week. As the country leaves lockdown, we know that demand will likely increase. However, when looking six weeks into the future, it gives us a good starting point.

We are also beginning to see that during this time of uncertainty, it has been useful to provide a range of values for the forecast. Better decisions can be made when the highest possible and lowest possible forecasts are included.

10. What do you think are the likely long-term consequences for balancing UK energy as a result of this current crisis?

We’re learning a great deal about operating the power system with both lower levels of demand and increasing levels of low-carbon generation. It’s all great experience to meet the challenge that we have set ourselves of being able to transition to a zero-carbon power system by 2025.

For more information about NGESO, visit www.nationalgrideso.com.