How come we still use steam moving dynamos to convert energy into electricity? It seems antiquated that even something as advanced as nuclear reactors still rely on this process. Are there obstacles in designing a better energy/electricity method?
In: Engineering
Relatively speaking, the use of steam turbines if pretty efficient due to the excellent heat transfer properties of water. So it falls in the category of “if it aint broke, dont fix it”.
You have to realize that the method depends on the kind of “energy” you’re talking about. Solar panels convert electromagnetic radiation (light) to electricity, hydroelectric dams convert gravity to electricity (via water fall / water pressure), and batteries convert chemical reaction energy to electricity.
And the obstacle is materials. We don’t know of a material that would convert radiation (such as in nuclear reactors) to electricity, and we don’t have a material that efficiently converts heat to electricity ([there are materials](https://en.wikipedia.org/wiki/Thermoelectric_effect#Seebeck_effect) that generate some electricity from heat, but not on the grand scale that we consume).
So, ultimately, boiling water to generate pressure to turn turbines, however inefficient the process, ends up being the best large scale method we have. Convert heat to pressure/motion, then pressure/motion to electricity (using magnets and copper wires).
There’s a lot of chemical energy stored in the stuff that we burn (burning is a chemical reaction), much more than what we can achieve with the chemical reactions in batteries.
Water has some stupendously useful properties. It’s easy to boil, and steam is able to store a great deal of heat energy without coming apart into hydrogen and oxygen. That heat energy can be converted into electricity at high efficiency using a turbine, a device with only two moving parts.
In addition, water is environmentally friendly, if you spill it on the ground, no messy cleanup. It is everywhere **and** it is cheaper than almost any other substance at a constant purity level.
Steam driven turbines are a way of converting a temperature differential into rotational motion and thus into electrical power.
There are devices (thermocouple) that can convert temperature differential directly into electrical power, but they are inefficient. I don’t know enough about semiconductor physics to tell you why.
Steam turbines are efficient for a few reasons. One, we can make devices for rotational motion that have very low friction, through the use of bearings and whatnot. Using heat to boil water into steam is also a very efficient process.
In general, improving the efficiency of something like a steam turbine is more within our capabilities because the things that can be improved (friction, insulation, heat exchange) are all things that can be tinkered with at a macro level. Improving the efficiency of a semiconductor device like a thermocouple (or solar cell) is a bit harder, because the relevant processes happen at atomic scale.
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