The ability to do work is called what?

Work is a concept in physics that does not get used much in biology. In physics they talk about "pound-feet per second" but in biology they talk about "draft animals", and "work" has a slightly different meaning.

Many people think "energy" is the ability to do work, but it's not. They say work is disordering of energy. Put those together and you have "energy is the ability to do disordering of energy". That is called a circular definition. Energy is not a physical unit. It is a philosophical concept and an accounting technique used to analyze mechanical and chemical exchanges. In nuclear physics it is defined as a wavelength of light, in biology it is a synonym for metabolism, and in public utilities they say energy when they mean connectivity. Anybody who uses the word in any other context either does not know what he is talking about, or is peddling something you don't need.