The aluminium smelting plant has been a major employer on the island
Plans have been submitted for a biomass plant near a smelting works where hundreds will lose their jobs.
Anglesey Aluminium has submitted the application to the Department of Energy and Climate Change.
The current aluminium works, near Holyhead on Anglesey, stops production next week with the loss of 390 jobs.
But if the electricity-making biomass plant is given the go-ahead, there is no guarantee production could restart at Anglesey Aluminium.
The decision to stop production was taken after the firm said a viable solution could not be reached to save the current workforce, and rejected a £48m four-year aid offer because it was "not enough to break even".
The company had wanted an extension of its deal to buy electricity cheaply from nearby Wylfa power station.
Politicians and unions were critical of the company, and workers staged a protest march through Holyhead.