That Interesting ROB.............This one uses hot water from about 4500' deep in the ground; it comes out at about 350º, and to keep it from boiling, it's under about 250 pounds of pressure.
The hot water goes through a heat exchanger, and is put back into the ground a few miles away.
The turbine is spun by a motive fluid that becomes a vapor when it hits the heat exchanger. Sort of like a refrigeration cycle, but in reverse.
I've done several gas turbine plants too. They're called 'peaking plants', because they use natural gas in the summer when it's cheap, and when the demand for electricity is high. They operate only when demand peaks, hence 'peaking plant;.