Since 2012, the need for the expansion and conversion of the grid is determined in a three-phase procedure. This is regulated by the Energy Industry Act (EnWG) of 2011. On this basis, the four transmission system operators 50Hertz, Amprion, TenneT and TransnetBW draw up a grid development plan (GDP) each year. This plan determines the need for the conversion of the high voltage grid as established by the transmission system operators. It is considered by the authorities and confirmed by the Federal Network Agency. Finally, the German Federal Parliament integrates the confirmed plan for grid development in the so-called federal requirement plan.
More information on this subject can be obtained on the website created by the four transmission system operators for the Grid Development Plan and from the Federal Network Agency.