The Green-ILC project as well as other initiatives at the ESS, CLIC and others are meant to be merged in a more global endeavor beyond projects and frontiers, because the energy consumption challenge is quite universal.
The first joint meeting actually started, at the last LCWS2014 (International workshop on future Linear Colliders) in Belgrade (Oct. 2014) and at  HF2014 (55th ICFA Advanced Beam Dynamics Workshop on High Luminosity Circular e+e- Colliders – Higgs Factory). A common session the “green session” was organized and 5 talks were presented. (see here and here (Thursday Oct 9 at 18:) as well as the summary talks (here and here).