People love measuring energy and there seems to be an insatiable appetite for different ways of doing it. Watts, foot-pounds, joules, calories (gram calories and food calories), Btu, horesepower, the list goes on.

Historically, each industry seems to have come up with its own way of measuring energy based on quantities that make sense to them. This might have been fine when people worked mainly in their silos, but these units of energy are used by normal people these days.

The first time this really ever seemed like a problem to me was while reading David JC MacKay’s excellent book Sustainable Energy - without the hot air. He is very careful about converting all the units in his book into watts and kilowatt hours. This means that he is able to compare what initially seem like unlike quantities; how do the calories in butter relate to the energy in petrol? If they are both measured in kWh then it is easy.

I guess I’m just channelling MacKay with this post, but if everyone thought in terms of kWh for everything then it would be a easy to understand how many Mars bars cycling 10km is equivalent to, or how many Mars bars leaving your computer on all day is equivalent to. Then, and this is a bit of a long shot, there might not be so much ill informed discussion about the environmental effects different plans and behaviours, or the effect of certain types of exercise.

Today’s rant really boils down to making it easy for people to think about the world with a consistent set of tools rather than having to reinvent their heuristics every time they change domains.