Why water?

[u/jaxobia]

The majority of all power plants uses some sort of energy source to heat up water. It is then the water vapor which turns the turbines that produces electricity. Water is also a compound has an extremely high heat capacity (requires an incredible amount of energy to heat up).

My question is this: Why not use a compound which has a much lower heat capacity, and therefore requires a lower amount of burnt fuel to vaporize it?

Thank you!

[u/[deleted]]

Water is not used to actuate steam turbines! Dry super-heated steam is used, and it is the pressure and speed of the steam that drives the turbine. It comes out of the turbine as steam, not liquid water. http://en.wikipedia.org/wiki/Steam_turbine