There was a recent announcement on the OpenCms mailing list about a new Alfresco add-on that allows you to publish content from Alfresco into an instance of OpenCms. The project is called Alfresco-OpenCms. You can get the documentation here. I haven't tried it out yet but the documentation shows examples in a normal Alfresco "Space" rather than a "Web Project." Web Projects are still relatively new and do not yet have all the capabilities that normal Spaces do so I am not sure that the module would work for a Web Project.
Perhaps the key value to this component is that it allows you manage content within Alfresco's sophisticated repository and leverage OpenCms's more mature web content delivery functionality. For example, maybe you use Alfresco for internal collaboration and document sharing and then you publish some assets to your OpenCms powered corporate web site.