Grid services exploit an emerging distributed computing technology that offers possibilities for distributed resource sharing and collaboration. The standards for WSRF (Web Service Resource Framework) have allowed grid services to converge more closely on web services. Composing web services has attracted significant effort and commercial interest. This has resulted in BPEL (Business Process Execution Logic) as a standard way of orchestrating web services. Because of the similarities with web services, there is a natural question of whether grid services can be orchestrated in like manner. It is explained how CRESS (Chisel Representation Employing Systematic Specification) has been extended to describe grid service composition. It will be seen how BPEL has been adapted for this purpose, using ActiveBPEL as the orchestration engine and Globus Toolkit 4 as the grid service container. The problems arising with orchestrating grid services are discussed, along with possible workarounds
