On the wikipedia page for "Molecular motor", it says "In terms of energetic efficiency, this type of motor can be superior to currently available man-made motors." without any references to back it up. Is this true in general and how would we go about comparing for example a diesel engine with the F1-ATPase, in terms of efficiency?
I think that statement is misleading because it is too vague. Yes diesel and gas engines are inefficient, however electric motors typically average between 80-95, depending on the range of rotation speed and torque, (i,e. slow speed and high torque out of design range), they can get hot and waste 20-50% efficiency. The best EV motors are currently hitting >95% efficiency at a high range of rotation speeds.
Molecular motors have been claimed to reach nearly 100% based on limited studies (ATP synthase), however most of them are in far lower ranges than electric motors " Henry Hess of the University of Washington explains that cytoskeleton motor proteins “convert their chemical energy with >50% efficiency into mechanical energy."
It is referencing an out of date study poorly.
The efficiency of F1-ATPase has been measured at so close to a hundred percent that the margin of error of the measurement, exceeds the difference. BUT this margin of error was almost 10%. The statement was accurate when the measurements were taken, around 1999- 2000. Before the highest efficiency electric motors were common knowledge, so the statement was sort of true back then. Of course the step right before F1-ATPase, F0-ATPase only runs at around 50% efficiency.
It can be really hard to measure the efficiency of individual components of a biological process, the process as a whole from sugar to ATP is around ~40% efficient. which is still high for anything that consumes a fuel. https://www.cell.com/fulltext/S0092-8674(00)81456-7