In engineering and energy, is there any difference between a system and a plant? Is it a matter of scale?

It sounds odd to me to use the word "plant" to describe a small-scale system for energy production (something non-commercial, for example a solar power system that could be installed on an individual person's property). I think of a power plant as being a very large structure for industrial or commercial purposes, but I haven't been able to find any reference sites that would justify my reaction. Am I wrong? Does anybody know any rules on this?

This is for a translation into English. The client's first choice is "plant." Thanks very much.

  • Can you please provide some context, possibly a sentence or two. Normally, a "power plant" refers to any system producing power. Jul 26, 2016 at 13:49
  • "The cooling is accomplished by additional refrigeration systems/plants connected with the engine." or "Pure water is produced by systems/plants based on evaporation and condensation processes." or "Engine performance and desalination system/plant outcomes are reported..." etc.
    – M Too
    Jul 26, 2016 at 14:06

1 Answer 1


For the context you're describing:

  • A system is a collection of things that work together to accomplish a purpose (see M-W; #1d).

    A system can be any size, from microscopic to astronomical. A system can be located in a building, or even be a network of things, some of which are contained in buildings, but typically, the building isn't an integral part of the system. There are exceptions, or a system can be integrated into a building, but usually, the building is just a place where the system is located, and might protect it from the elements if the building's purpose is specifically to house the system.

  • A plant usually refers to a building or collection of buildings at a location, the associated land, and the equipment there, which are employed in carrying on a trade or an industrial business or producing a certain "product" (which could be power). A plant may contain one or more systems or could be part of a network composing a system. (see M-W; noun #2).

If you're talking about a small device or system installed on someone's property, that would typically be referred to as a "system", "device", "machine", or a term for the specific kind of thing it is, rather than a "plant".

However, "a term for the specific kind of thing it is" complicates things. A "plant" can be any size, there isn't a specific size threshold below which something can't be called a "plant'. A power generation facility is referred to as a "power plant".

For roughly the last half century, there have been miniaturized power generation modules that serve the function of a power plant in remote areas. They have been referred to as a "power plant". The term has also been applied to the power generation module for things like space craft or landers (well, that's probably covered by "remote"). It isn't normally applied to something like a battery, that just stores power, but to something that creates power.

So if a power generation module is a "power plant" in a remote area, there's precedent for calling it the same thing if you stick it in someone's backyard.

  • I don't know about the US but in the UK you can also have "mobile plant" which usually refers to large earthmoving equipment like bulldozers, diggers or scrapers. These are big but still small enough to be mobile, often small enough to travel on public roads. Also the motors of lifts (elevators) and air conditioning installations in medium to large buildings are often housed in "plant rooms". I know this doesn't refer to power plants but is, I think, an interesting aside.
    – BoldBen
    Jul 12, 2017 at 23:05

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