Grid computing environments are heterogeneous in terms of the types of computer systems, the applications being run, and the policies governing the use of systems. To support automation in such environments common models to describe systems, applications and scheduling policies are needed.??Common models enable the interoperation and reuse of tools transparent to the underlying differences in the environment. This paper relates our experiences in using modelling to support automation in grid environments. We have developed RDF-based models for describing systems, applications and scheduling policy. A GT4-based grid environment consisting of computer systems from across Canada has been established with model information deployed and published via WS MDS.??Several examples demonstrating the use of modelling to support automation in the established grid environment are presented.