The Powerlink consortium won the job back in 1998 but LU has now given notice it will be making use of a 15-year break clause next August.
Powerlink is made up of UK Power Networks (80%), Balfour Beatty (10%) and ABB (10%).
The consortium currently employs 270 staff overseeing the supply and maintenance of power for the tube network
LU said both sides “will work together closely over the coming months to ensure a smooth transfer of staff and activities back to LU next year.”
Sarah Atkins, LU Commercial Director, said: “We’ve taken a good hard look at every aspect of how we operate the railway and found that we can make significant savings by terminating this arrangement early, avoiding expensive financing costs that would have come with continuing the contract to its end.
“Although the contract has been performing well, the move to restructure the PFI arrangement will give us increased operational flexibility, and mean we can invest the savings made in further transport improvements for our customers.”