Power Pause Update 2

 Another Power Pause, another Payday! Offer to participate in the next Power Pause on January 17th was accepted. The Air Source Heat Pumps were turned down a couple of degrees for the one hour duration of the pause and we spent a pleasant hour reading ...

Photo 1: My Reading Choice

Photo 2: Mary's Reading Choice

There was no noticeable change in room temperature despite the sub-zero outside temperatures (-2 ℃) and I had prepared the evening meal (vegetable stew) much earlier in the day using the slow cooker. A few days later we were informed that we had saved 1.846 kWh in energy and earned a rebate of £4.92 (i.e £2.67 per kWh).

In the 2022 trial, 1.6 million households and businesses participated in the Demand Flexibility Service and saved 3.3 GWh (enough to power 10 million UK homes). It isn't clear whether each "Power Pause" had that many participants or that it was just the total number of individual participants over several events.

In addition to easing the National Grid's job of balancing electricity generation with consumer demand, the Demand Flexibility Service has other useful benefits. For example, by maximizing the use of cheaper renewable energy at the expense of the costlier fossil fuel generators. Figures 1, 2 & 3 were taken from the grid.iamkate.com website and show the generation sources used to meet the demand for electricity on Tuesday 16th January (Figure 1), Wednesday 17th January (Figure 2) and Thursday 18th January (Figure 3) this year. Wednesday was the day of the Power Pause.

1. Electricity demand was fairly constant over the three days (38.8 - 39.8 GWh) but there was a significant drop (3 GW) in power generation from renewables on the Wednesday
2. From the weather forecast, National Grid would have expected the drop in power generation from renewables (mainly wind)
3. Also from the weather forecast, National Grid would have been aware that daytime temperatures on Wednesday (maximum 2 ℃ in Hereford) would be lower than either Tuesday (maximum 7 ℃ in Hereford) or Thursday ( maximum 5 ℃ in Hereford)
4. Following on from points 2 & 3, any extra demand for electricity on the Wednesday would need to be met by bringing expensive and polluting fossil fuel generators online
5. So Wednesday was a good choice for testing the Demand Flexibility Service

Figure 1: Generation/Demand on Tuesday 16th January 2024

Figure 2: Generation/Demand on Wednesday 17th January 2024

Figure 3: Generation/Demand on Thursday 18th January 2024

By avoiding the use of additional fossil fuel generation, the carbon intensity of the electricity grid is minimised. An additional benefit is the reduced cost of electricity possible by limiting the use of expensive fossil fuel generation.

Figure 4 (taken from grid.iamkate.com) shows the UK Electricity Grid prices during the week beginning Saturday 13th January 2024 and including the latest Power Pause on Wednesday 17th January. Note the small price drop on Wednesday brought about by the use of the Demand Flexibility Service along with some extra electricity imports, especially from France. By avoiding the need to pay coal-fired power stations to fire up just in case, the overall price of electricity reduces.

Figure 4: UK Electricity Grid Prices for Period 13/1/24 to 19/1/24

[Note: the price drop on Friday can be attributed to a large increase in wind-powered electricity; up from 7.34 GW on Wednesday to 15.48 GW on Friday while demand was constant at around 39 GW]