Which Type of Geothermal Power System is the Best?

[chemisthypnos]

There are three geothermal systems that are commonly used: sry steam, flash steam, and binary cycle https://www.eia.gov/energyexplained/index.cfm?page=geothermal_power_plants . What are the efficiencies of the plants from best to least effecient on average?

 

[anorlunda]

None of the three are necessarily more efficient.

Dry steam versus flash steam depends on the conditions under the ground. How hot is it down there? If hot enough, the fluid comes out of the ground as steam. If cooler, it comes out as hot water.

The biggest design decision for a geothermal power plant is how to deal with minerals and contaminants in the steam. Have you ever tried to taste the water that comes up in a geothermal spring?

Contaminants foul the turbine blades and cause the efficiency of the turbine to degrade over time. Other components, heat exchangers, flash tanks, and piping can also be fouled by contaminants. Sometimes that requires frequent shutdowns to clean the components.

The binary cycle type of plant includes extra equipment and extra cost to make sure that the steam through the turbine is clean and free of contaminants. Still everything on the primary side of the heat exchanger needs cleaning, but that's easier than cleaning the turbine.

So the short answer to your question, is that cycle efficiency in a geothermal plant is not as important as dealing with contaminants.

 

[chemisthypnos]

I have never tried to taste the water from a spring because I live in NY (USA), but it sounds like an interesting experience from what you describe! Thank you for your helpful explanation and for your time.

 

[anorlunda]

Go to Saratoga Springs NY or Sharon Springs NY for mineral water.

 

[Asymptotic]

I have never tried to taste the water from a spring because I live in NY (USA), but it sounds like an interesting experience from what you describe! Thank you for your helpful explanation and for your time.

I'd pass no fewer than two springs (four, if counting two spring fed ponds) on the mile walk home from our school bus stop. Located a crowd-sourced map of spring locations; the closest shown on it is fifteen miles away, bit I know of at least a dozen other springs betwixt here and there. Not thermal springs, mind you ;)

 

[chemisthypnos]

Wow. I never realized that there were so many in NY. I guess that you learn something new everyday.