poyndexter, based on your list of geothermal related companies i also did some research.
I today bought a few thousand dollars worth of shares in each of the four companies you mentioned ie GHT, GDY, PTR, & GRK. You did mention a few others, one of which is involved in sequestation but I left that alone.
I may be in for a few days or a long time but I will watch them closely.
regards and thanks