The major activities carried out for geothermal electricity generation since WGC2010 have been analyzed.
An increase of about 1,7 GW in the five year term 2010-2015 has been achieved (about 16%), following the rough standard linear trend of approximately 350 MW/year, with an evident increment of the average value of about 200 MW/year in the precedent 2000-2005 period.
The total installed capacity from worldwide geothermal power plant is given in tables I and II and in figures 1 and 2.
For reaching the forecasting of 2020, based on an accurate accounting of all the existing projects at an executive stage, a clear change in the present linear growing trend should be necessary.