National Grid warns of power demand controls

LONDON (Reuters) - The closure of several power plants on Tuesday has cut supply so severely that distribution companies should reduce voltage to customers to compensate, a spokesman for network operator National Grid said.

Utilities responded to National Grid's earlier warnings on Tuesday that there was not enough supply available to operate the system comfortably by starting up some backup units.

But it was not enough to make up for the loss of other plants, including British Energy's Sizewell B nuclear reactor, and so the shortfall of 400 megawatts will need to be compensated for by reducing the strain on the network.

"Just over the peak period ... we will need some form of demand control but the distribution companies can reduce the voltage slightly and that makes the available electricity go a lot further," he said.

"It's not something that customers should notice."

British Energy said on Tuesday its 1,180-megawatt Sizewell B nuclear power reactor was shut down around midday but that it was already working on a restart plan.

Data from a website run by the grid operator showed that Scottish Power's 576-MW Longannet 1 coal fired power plant and the 793-MW South Humber 1 gas fired unit, and EDF Energy's Cottam-3 coal plant also stopped on Tuesday. Other units have also been stopped.

(Reporting by Daniel Fineren)