National Grid have published the three Triad dates for the 2019/20 season, which are listed in the table below. For an eighth consecutive year EIC has successfully called an alert on each of these days.
There was a significant reduction in the number of Triad calls this year with EIC only issuing 13 alerts in total, nearly half the number called the previous winter. This compares favourably with other suppliers who called an average of 24 alerts across the Triad period.
Triads are three half-hour periods with the highest electricity demand between the start of November and the end of February. Each Triad must be separated by at least 10 clear days. This means consecutive days of high demand won’t result in multiple Triads. If consumers are able to respond to Triad alerts by reducing demand then they will be able to lower their final transmission costs.
Lowest peak demand for 27 years
Peak demand is at its lowest point since 1992/93 and is now 14 GW (~24%) lower than the peak of 2010/11. There are a number of factors that have contributed to the fall in peak demand over the past decade. These include improvements to the energy efficiency of appliances, an increase in LED lighting and a rise in embedded generation.
Embedded wind output peaked at 3.4 GW during the Triad period. As embedded generators are connected to local distribution networks, this displaces a similar amount of demand from the transmission network. Therefore, peak demand is typically higher on days with low wind which increases the risk of a Triad occurring. This trend can be seen in the graph below which shows that for every 1 GW increase in embedded wind output there was an associated drop in peak demand of 0.9 GW.
Mild January leads to new record
For the first time since the Triad methodology was implemented, all three Triads have occurred before Christmas. This is mainly due to the mild and windy weather conditions experienced so far in 2020.
In terms of temperature, we’ve seen the mildest January since 2007 and second mildest in past 30 years. Across the Triad season only six weekdays had an average temperature below 3°C with only one of these occurring after Christmas. This compares to 17 the previous winter and 23 for the 2017/18 winter.
Wind generation increased throughout the Triad season with a pre-Christmas average of 6.5 GW significantly lower than the January and February average of 9.2 GW. As the weather conditions in November and December were generally colder and calmer, this increased the probability of Triads occurring during this period. Subsequently, all three Triads fell before Christmas on days when temperatures were below 4°C and wind power was less than 5 GW.
Demand response results in March peak
Peak demand on 5th March was higher than any day within the Triad period which can be seen in the graph below. The weather conditions on this day were demand supportive with an average temperature of 4°C and wind power around 5 GW. In comparison, on the 20th and 21st January weather conditions were similar, however peak demand was around 1.7 GW lower. This demonstrates the effect that Triad avoidance has had on reducing peak demand over the past few years. It also suggests that peak demand may start to increase after next winter without the incentive to consumers of reducing transmission costs. The elimination of a number of embedded benefits for generators is expected to limit the growth in embedded generation which will also have an effect on peak demand.
Demand response also led to a Triad falling between 4:30pm and 5pm, which is the earliest occurrence in 22 years. This Triad was, in fact, missed by one supplier who advised consumers to reduce demand between 5pm and 5:30pm. As some businesses are only able to reduce demand for short periods, the largest volume of demand response is typically seen between 5pm and 6pm. This has the effect of flattening the evening peak and increasing the risk of the peak half-hour falling either side of this window, as was the case on 17th December. All 13 Triad alerts issued by EIC covered the correct HH period, comparing favourably to an average success rate of 78% across other suppliers.
TCR Final Decision
In December, Ofgem published their final decision on the Targeted Charging Review (TCR). The main outcome of this decision is that from April 2021 the residual part of transmission charges will be levied in the form of fixed charges for all households and businesses. This means that there is one final chance for consumers to benefit from Triad avoidance over the 2020/21 winter period.
The TCR aims to introduce a charge that Ofgem considers is fair to all consumers and not just those able to reduce consumption during peak periods. For the majority of consumers these changes will lead to a reduction in transmission costs. However, for those who are currently taking Triad avoidance action it is likely that their future costs will rise.