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How do you turn on a £1bn power station?

19 September 2012 Last updated at 13:27 BST

A ceremony has been held to mark the completion of a £1bn gas-fired power station in Pembrokeshire.

RWE npower has said its Pembroke Power Station, the largest of its type in Europe, will power 3.5 million homes.

Earlier in the day the BBC's Adam Parson spoke to Robert Day about how the power station would be turned on.