Toei is handling the home video release and they’ve set a March 6th, 2019 debut for it as a Blu-ray only release.
But even now, Z-chan and Gre-chan use the highly efficient photon energy to power their home.
Plot Concept: The show is set in a ruined future Nerima, where a photon energy disaster is said to have devastated the area.
With some fun and successful material with Robot Girls Z out there, Toei and Dynamic Planning brought back more of this property with a new series called Robot Girls NEO last summer.