Peak UK electricity summer demand set to fall by almost 2GW

Peak electricity consumption in Britain is expected to be almost 2GW lower this summer compared to what they were forecasting 2015, National Grid revealed in its summer outlook on Thursday.

Demand is forecast to peak at 35.7GW, down from peak forecasts of 37.5GW last summer, the lowest on record.

Although underlying demand is expected to remain flat to last summer, the rapid increase in the UK’s installed solar capacity over the last 18 months is set to take a greater chunk out of grid demand this summer.

All solar installations are connected to local distribution networks in the UK and do not feed into the National Grid’s main transmission network. Forecasts for solar generation are therefore deducted from forecast grid demand.

The system operator estimates 9.3GW of solar capacity is installed as of February 2016 and that this figure is increasing by 200MW per month. “This equates to 12GW by the beginning of British Summer Time 2017,” National Grid said in the outlook.

“As supply becomes increasingly dependent on weather, we are working with a number of stakeholders to improve our solar generation forecasting,” National Grid director Cordi O’Hara said.

System constraints

Minimum demand is also forecast to be lower this summer, with the lowest daytime consumption of 23.5GW expected to fall during the last weekend of July. This is 2.5GW lower than last summer’s minimum demand forecast.

National Grid warned it might need to curtail wind generation and issue emergency instructions to inflexible generators to reduce demand during minimum demand periods to help balance the system.

“Based on current data, there is a risk that we may need to ask inflexible generators to reduce their output during the weeks commencing 20 June, 25 July and 29 August,” National Grid said.

Declines in system demand that could lead to oversupply will also be managed through a new demand turn-up service that is set to launch at the start of May (see EDEM 22 February 2016).

The system operator has also urged wind farms and generators to submit cost reflective prices to the balancing mechanism in order to manage low demand periods economically and reduce wider wind curtailment.

Interconnectors

The 500MW Moyle Interconnector linking Northern Ireland to Britain is also expected to return to full capability this summer following the completion of cable replacement project, National Grid said. The cable is currently operating at half its nameplate capacity. The outlook can be viewed here . henry.evans@icis.com