Mr Miliband said: "That is why we will freeze energy bills until the start of 2017 and then we will sort out the way the energy market works to stop people being overcharged.
"That is where my focus is this morning."
As Ed Miliband clashes with the energy giants on prices, it is worth knowing how your expensive energy bills are actually made up.
A leading competition lawyer says an energy price freeze could leave Labour open to challenges from the courts or the European Commission.
Whether or not you approve of a state intervention into industry, there are at least two big potential obstacles for an energy price freeze.