National Grid issues supply margin alert
National Grid issued a Notice of Inadequate System Margin (NISM) on Wednesday 4 November for the first time since 2012. A NISM is a signal that National Grid can send to the market so that generators can help it to manage the system by making more power available. The company made the move at 1.30pm as a consequence of outages at several plant and low imports from Europe; it requested an additional 500MW of power for the period between 4.30pm-6.30pm. The NISM was withdraw at around 6pm, with National Grid confirming that it had, for the first time, employed its Demand Side Balancing Reserve. This reduced demand by 40MW.