At May 23rd, 2017 a joint workshop regarding the development of a CityGML Energy Application Domain Extension (ADE) will take place at CSTB in Grenoble, France.
The Workshop is supported by CSTB, OGC and SIG3D and is an opportunity to gather requirements, ideas, suggestions, and experiences from CityGML users, data producers, software vendors, and scientists developing and using the CityGML Energy Application Domain Extension.
Further information at the EnergyADE wiki page.