the article, page-16

There seems to be confusion.

This is how the Kalina Cycle works - similar steps can be applied to the Rankine Cycle.

1) Hot geothermal fluid, under high pressures, is extracted from the hot fractured rock reservoir through a geothermal well.

2)This geothermal fluid enters a heat exhanger, where it transfers a percentage of it's heat energy to a working fluid (ammonia/water mixture in Kalina, O.C in Rankine) which is also under high presure.

3)The working fluid vaporises, creating gas under pressure, which drives the turbines, generating theelectricity.

4)Upon cooling, the working fluid returns to the first stage in the loop, to be heated again. The geothermal fluid is reinjected into the ground.

There is no part in this cycle in which a turbine is driven by pure steam. The primary phase is not steam driven - transfering heat from water to water is inefficient compared to tranfering heat to an ammonia soln. or even an O.C. So to say the bulk of the energy is generated in a primary steam-driven phase seems misleading. Ammonia in solution is a much better workhorse than butane or pentane (O.Cs).

So the process is highly influenced by the quality of the working fluid.

Anyway, you don't sound like you need convincing on which GEO to buy.... the people who got in the IPO are looking at a great return.