National Grid has predicted all-time lows for power demand on the transmission system this summer due to the boom in distribution-connected solar PV.
The system operator also warned that it may have to issue emergency instructions to inflexible generators over the summer, whom it will pay to stop exporting power onto the system. It may also need to call on new demand-side response tools that ask firms to increase power use.
According to Grid’s Summer Outlook, the peak demand forecast for high summer, at 35.7GW, is the lowest on record, some 2GW lower than last year. Daytime minimum demand is expected to be 23.5GW, around 2.5GW lower than the minimum demand experienced in 2015.
Those drops are driven largely by increases in embedded solar PV capacity, which, according to Grid figures, almost doubled from 5.0GW in April 2015 to 9.3GW in February 2016. The system operator has assumed PV will continue to increase, albeit at around half that rate, by 200MW per month over the next year. It predicts total solar PV capacity to reach 12.0GW by the start of BST 2017.
The system operator said forecasts indicated it would have sufficient capacity to meet demand, even with low interconnector imports during July and August, when generators tend to carry out annual maintenance.
However, Grid said the changing generation mix and demand profile would require more direct system operator intervention and a more flexible approach to system balancing.
It may use demand-side response tools, such as the new demand turn-up scheme, should the system have more power than it can cope with, as well as asking inflexible generators to reduce their output. Current data suggests that will most likely happen during the weeks commencing 20 June, 25 July and 29 August, said Grid.
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