"The market on its own is not going to ensure that we make the transition to low carbon," Mr Miliband told the news provider.
"It's not necessarily going to ensure the right diversity in our energy mix."
He added that the time of leaving the development of the energy sector to market forces was over and that a long-term framework was needed to ensure the successful overhaul of the National Grid in the coming years.
Vincent de Rivaz, chief executive of the UK subsidiary of EDF, told the Financial Times that a new generation of nuclear power stations would not be built unless the government provided financial support.
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