Britain uses coal-power back up for the first time with supply tight

By Nora Buli and Susanna Twidale

(Reuters) -Britain's National Grid called on reserve coal-power units for the first time to provide electricity during a period of expected tight supplies on Tuesday as a cold snap sweeps the country.

The energy grid operator warned in October that homes could face three-hour rolling power cuts this winter if the country was unable to secure enough gas and electricity imports.

Contracting some coal plants to remain available is part of its tool box to help prevent cuts.

National Grid's Electricity System Operator (ESO) said two coal units at EDF's West Burton coal plant had been synchronised to the grid on Tuesday afternoon.

Coal plants under the scheme have been readied for use several times this winter but this is the first time they have been needed.

The extra generation enabled the grid to cancel an electricity margin notice (EMN) it issued late on Monday evening flagging it would like more power generation to be made available for 1630-2030 GMT on Tuesday.

The two coal units were later allowed to de-synchronise from the grid after that window of expected peak demand ended at 2030 GMT.

Britain's Met Office has warned of sub-zero temperatures overnight on Tuesday and issued warnings snow and ice could disrupt transportation.

Separately the grid also said it would not issue a demand flexibility service (DFS) requirement notice for March 8, having earlier said one might be needed.

The DFS rewards people, usually through discounts on their bills, for turning off appliances such as ovens and dishwashers during a specific period when electricity demand is high.

(Reporting by Nora Buli in Oslo and Susanna Twidale in London, additional reporting by Deep Vakil in Bengaluru; Editing by Louise Heavens, David Goodman and Christina Fincher)