An official Ofgem response to npower's company costs announcement read:
We welcome npower's effort to inform the energy debate, however their data on network costs is incorrect and misleading.
We offered to help npower improve the accuracy of their numbers for network charges and it is disappointing that they did not engage fully with us until after the document had been circulated.
Ofgem directly regulates the money that network companies can earn through charges.
Given this level of certainty we can see that after 2014 network costs per household are expected to remain broadly flat in real terms.
It is unclear how npower can state with any authority otherwise.