UK’s solar fleet helps reduce power demand to lowest level in eight years

Improved energy efficiency in consumer electronic goods, and a marked reduction in energy-intensive heavy industry have certainly been factors in helping Great Britain (excluding Northern Ireland, so not the U.K. as a whole) register its lowest quarterly power demand for eight years, but the role of distributed solar power embedded into the system cannot be overlooked – that is the conclusion of the latest Q2 2017 GB Electricity Market Summary Report by EnAppSys.

According to the data, average half-hourly power demand in July was 26. 2 GW, and average half-hourly gross demand was 29.2 GW – the former the lowest monthly total since 2009, the latter a record low. With 3 GW half-hourly average of embedded generation, the impact of solar’s rise has been stark, the data showed.

Throughout the month of July, average solar generation between the optimum hours of 10am and 2pm was 4.4 GW per half-hour. This helped reduce peak demand by 13% from the gross average of 34.1 GW. Cumulative solar PV capacity in Great Britain now stands at 12.5 GW, the EnAppSys summary shows, and on July 17 a generation peak of 7.3 GW of solar was recorded.

“The increase in embedded generation, particularly solar, has had a noticeable effect on the daily demand curve,” said EnAppSys analyst Katie Fenn. “It is now common to see a dip in demand in the middle of the day. Whilst this makes it difficult for large units to achieve long runs, and so reduces the spinning reserve online, this may not be such a big problem for system stability as it might appear, as fewer large units on line reduces the likelihood of a large single point of loss.”

Combined with nuclear, ‘clean’ electricity met 53% of power demand in Q2, ranging between 36% and 72% across the quarter depending upon weather conditions. Renewables alone contracted 3.5% against Q1, but this is largely due to the less windy conditions of the spring and summer months. Year-on-year, however, renewable capacity was 56% higher in Q2 2017 than it was in Q2 2016.

Solar energy accounted for 19% of the renewable share, providing 4.1 TWh of generation over the quarter.