I have been trying to get an org-mode to output an agenda to the Windows command prompt.
This worked easily under linux with the following switches on the command line:

-batch -l <<<path>>>/init.el -eval '(org-batch-agenda "a" org-agenda-ndays 30)'

I eventually got this working under Windows by replacing the single quotes with double quotes and replacing "a" with """a""".
So the working parameters are

-batch -l "<<<path>>>/init.el" -eval "(org-batch-agenda """a""" org-agenda-ndays 30)"