Over the last month I have started contributing to a very interesting project I found on code.sdn.sap.com. This project has the goal to create excel files directly with abap code. There is no office integration needed through the GUI and files can be created therefore even in the background. A lot of effort has been already but in the first versions of this great idea. In the moment version 7 is in the works and version 6 has been released beginning of this year. There is a lot of work pending, but it is already very much usable and has already a big fan base (more than 300).
I can only recommend to have a look and try it out. Here you can find more info ABAP2XLSX.