Geothermal power generating system in which turbine/generators are driven by hot gases and energy from a geothermal source. Both terrestrial and marine embodiments are disclosed and, in some embodiments, include a support structure positioned above a source of geothermal energy, one or more turbine/generators suspended from the support structure by a deployment system that can move the turbine/generators toward and away from a source of geothermal energy, heat sensors on the turbine/generators for sensing heat from the geothermal energy source, a control system responsive to the heat sensors for activating the deployment system to move the turbine/generators away from the geothermal energy source if the heat from the geothermal energy source becomes too great. Some embodiments also have a containment housing which extends to a fuel source release point in the floor of a body of water, encloses the turbine/generator, and funnels gas from the release point to the turbine/generator.