E.ON has agreed in principle to transfer power production quotas from its decommissioned Stade nuclear power plant to the Biblis A reactor to extend operational life.
The agreement, which has yet to be signed, will enable RWE to operate the 1.2GW Biblis reactor.
The country's remaining 17 nuclear plants will have to be shut down by around 2022 with Biblis being the next in line.
RWE has been pursuing a multi-track strategy to achieve a longer operating life of the Biblis reactor.
In March RWE said it will run the reactor at a reduced capacity to allow it to operate the plant for about a year as opposed to only six months if the facility were to be operated at full capacity.