See if you are eligible for the 6 months Geothermal Training Programme of the United Nations University in Iceland. In any case, it would be good to contact them directly and inquire about possibilities for enrolling in their workshops and short courses. Follow the link http://www.unugtp.is/
I see. Well, I think there may be several other alternative programmes around the world if you search. For example, Geothermal Resources Council (GRC) might be a good place to start. Similarly, there may be others I guess.