Chengbei Transformer Station, the first 500-kv transformer station, whirred into action in north Beijing in June 2006.

Four other similar transformer stations will also be built by the end of 2007 to ensure an adequate electricity supply for the capital during the Olympic Games, sources said.

Both of the two transformer stations are funded and constructed by the North China Grid Company Ltd.

The head of the company Sun Gang said that the transformer stations would not only help meet the power demand during the Olympics, but also further improve the power networks of Beijing.