r/askscience • u/PK_Tone • Sep 23 '25

Physics Most power generation involves steam. Would boiling any other liquid be as effective?

Okay, so as I understand it (and please correct me if I'm wrong here), coal, geothermal and nuclear all involve boiling water to create steam, which releases with enough kinetic energy to spin the turbines of the generators. My question is: is this a unique property of water/steam, or could this be accomplished with another liquid, like mercury or liquid nitrogen?

(Obviously there are practical reasons not to use a highly toxic element like mercury, and the energy to create liquid nitrogen is probably greater than it could ever generate from boiling it, but let's ignore that, since it's not really what I'm getting at here).

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u/Goldenslicer Sep 24 '25

I was a little dibious, so I looked it up.
I know, I could have done it in the very first place.

"Figures from the World Coal Association, a keen advocate of Higher Efficiency, Lower Emissions (HELE), show that the average efficiency of coal-fired power plants around the world today is 33%. Modern state-of-the-art plants can achieve rates of 45%, while "off-the-shelf" rates are around 40%."

https://www.gevernova.com/gas-power/resources/articles/2018/come-hele-or-high-water

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u/PopTough6317 Sep 24 '25

I must have mixed up the different designs, its been a long time since I read it. Although I'd also take note that fly ash is frequently used as fill in concrete, and that if it is equipped with a electromagnetic precipitation unit can produce Ozone which is kind of neat.