Oil report

UPDATE 1-Britain's National Grid warns of system tightness for Wednesday

(Updates with comments, details)

LONDON/OSLO, Nov 4 (Reuters) - Britain’s National Grid has send out an electricity margin notice (EMN) for Wednesday evening as it seeks to increase spare capacity amid a tight power system.

National Grid is responsible for ensuring supply and demand are balanced in Britain’s energy systems.

The electricity system will be particularly tight between 16.30-18.30 GMT, “owing to a number of factors including the weather, demand for electricity and the availability of generators,” a National Grid spokesman said.

“This is a routine signal that we send to the market to indicate that we’d like a larger cushion of spare capacity,” he said.

National Grid is seeking an extra 477 megawatts of capacity.

The grid has a number of tools to help balance supply and demand such as asking generators to increase output.

EDF Energy said on Wednesday it was ready to fire up its West Burton A coal plant later today if needed.

“West Burton A... and provides a valuable back-up service at times like these and is ready to run when required,” an EDF Energy spokeswoman said via email.

At full capacity West Burton A can provide around 2,000 megawatts of electricity.

Reporting by Susanna Twidale in London and Nora Buli in Oslo, editing by Louise Heavens