Breakdowns force National Grid to issue power supply crunch alert

A series of power plant breakdowns and the partial failure of a key electricity import cable forced National Grid to issue an urgent call for more power to keep the lights on on Monday night.

One power plant was paid more than 30 times the usual price of power after the Grid issued the "Notification of Inadequate System Margin" (Nism) requesting more electricity be generated.

A Nism alert has not been issued in summer months since 2008 as the warm weather means power demand is normally lower.

But the combination of a large number of power plants being shut down for maintenance, the series of unplanned shutdowns and wind power being lower than expected together forced Grid to take the unusual step.

Experts said the multiple breakdowns - believed to be primarily old coal and gas plants - showed the urgent need for more investment in reliable new power plants.

National Grid said about  1,700 megawatts of capacity was unexpectedly taken off the system yesterday.

In addition, a problem forced the part closure of a National Grid-owned interconnector cable importing power from France, with the loss of another 500 megawatts.

At the same time, Britain's wind farms generated about 500 megawatts less power than expected.

National Grid issued an alert at 7pm calling for 1,500 megawatts of power plant capacity to start generating between 7pm and 9.30pm.

National Grid said the highest price it paid to a plant to help it through the crunch was £1,250 per megawatt-hour of power. It is understood this was to E.On's  Connah's Quay power plant.

Nism alerts used to be relatively common but had barely been used in the last few years due to a healthy surplus of power plants on the electricity grid. However, that surplus is being eroded as old coal plants are mothballed and shut.

In November, National Grid issued its first Nism since February 2012 and was forced to use "last resort" measures to keep the lights on by paying businesses to use less power.

Dr Jonathan Marshall, energy analyst at the Energy and Climate Intelligence Unit said that Monday's Nism alert showed "once again that the UK power system badly needs new investment".

"Seven sources of electricity failing simultaneously just shouldn’t happen, and the presumption must be that the age of these plants increased the chances of failure."

A spokesman for  National Grid said: "The notice that was issued is part of our standard toolkit for balancing supply and demand and when issued is not an indication there is an immediate risk of disruption to supply or blackouts; it is an indication that we would like our power held in reserve to be higher."

A spokesman for the Department of Energy and Climate Change said: "By issuing a NISM, National Grid is doing its job to make sure there is enough electricity to power our homes and businesses.

"It is simply a tool National Grid uses to ask power stations to respond and generate more electricity for a short period of time.

"We are clear that delivering energy security for our families and businesses is non-negotiable and this is just part of making sure they have secure and affordable energy supplies they can rely on."

A spokesman for E.On's power plant division Uniper declined to confirm the price it was paid.

Telegraph