GE Starts Up New Britain Power Station

General Electric could not be reached for comment on the status of the combined-cycle gas turbine plant at Port Talbot.

Grid data showed the plant had been flowing power onto the England and Wales network for several days.

"Baglan Bay is up and running, it looks to be well into the commissioning phase," said a trader for another generator.

The 300-million pound ($477.3 million) plant, one of the biggest investments in Wales in recent years, supplies power and heat to a local industrial park as well as power to the grid.

The start up of Baglan Bay comes as investment in new power stations in the UK slows to a trickle because of weak wholesale power prices.

Power prices have slumped 40 percent since 1998 on increased competition and overcapacity.

Critics of new power trading arrangements launched two years ago say the new market is not encouraging enough investment and Britain could face a shortage of generation capacity in future.