Hi,
if neither the har2gdx that comes with GAMS nor the har2gdx from Gempack works, I think your path via CSV is your best option. Unfortunately, the har2gdx tools are not well maintained and due to this GAMS has announced (
https://www.gams.com/42/docs/RN_37.html#g3710_GDX2HAR) to drop their version of the har2gdx/gdx2har tools from the distribution. There is also a Python package (
https://github.com/GEMPACKsoftware/HARPY) that might get you the har data into Python and then via e.g. GAMS Transfer Python (
https://www.gams.com/latest/docs/API_PY ... NSFER.html) into GDX. I did not experiment much with the harpy package, but activity on this is also very low.
If you succeed, it would be great if you could describe your "pipeline" so others can benefit from this.
Good luck.
-Michael