Imagine the huge energy potential which stays unexploited under our feet: only 0.1% of our globe is colder than 100°C.
One Km³ of 200°C hot granite cooled by 20°C delivers about 10 MW of electric power for a period of 20 years. One km3 of 180°C hot geothermal water cooled to 100°C delivers about 7 MW of electric power for a period of 250 years.
Put in another way; installed 1 MW is enough to supply 2500 homes every year.
Geothermal water has been used since the Roman time principally for bathing, but nowadays it is also a way to produce electricity even for low temperature sources of about 100°C.
Hot water coming from an aquifier source is pumped up. This natural source of heat is used to vaporise an appropriate working fluid mixture with a boiling point below 100°C. The vapour is then expanded through a radial inflow turbine which drives a generator and delivers electricity to the grid. The low pressure vapour is then condensed with an existing cold source (fresh water or ambient air) and the liquid is pumped back to the evaporator to begin the cycle again.
The hot geothermal water which was cooled by the cycle can be used for district heating and then returned to depth.
The Cryostar technology of high efficient radial inflow turbine perfectly matches the needs of this application. Unlike axial turbines, the efficiency of Cryostar’s expander can reach 90% or more !
Thanks to in-house developed tools, Cryostar engineers have the ability to optimise the process (mainly working fluid and pressure level) and the expander to offer to the customer the optimum choice taking recovered power and cost into consideration.
Application in Action
Cryostar is working with a German customer in order to provide a tailored turbine solution for a Geothermal application. The objective is to produce electricity from geothermal heat, with 100 l/s of geothermal fluid at 180°C. Operating a closed loop binary cycle, the appropriate fluid mixture is expanded inside the Cryostar turbine to produce 6 to 7 MW of clean electricity without any CO2 emission. The remaining low grade temperature is able to supply a local district heating network.
Cryostar Group
Cryostar is working with a German customer in order to provide a tailored turbine solution for a Geothermal application. The objective is to produce electricity from geothermal heat, with 100 l/s of geothermal fluid at 180°C. Operating a closed loop binary cycle, the appropriate fluid mixture is expanded inside the Cryostar turbine to produce 6 to 7 MW of clean electricity without any CO2 emission. The remaining low grade temperature is able to supply a local district heating network.
