Since being PO aware I have been trying to cut the 'energy fat', with an eye to being able to survive (comfortably) when my income was expected to drop at pension time.
Some of the projects, such as a ground-heat exchange system, is currently saving a lot of money. Using money as a proxy for energy there are great savings there. However, some other projects [to cope with extended power cuts rather than a collapse situation, although they will help with that] such as a hand pump on the well, or new windows, or the wood burning stove in the kitchen, have not been cost effective so far.
All in all the savings from cutting the fat (using less oil etc) have been plowed into other areas which has left me better able to cope with a transition time to lower energy. In my case work has been transferred from the oil industry (ie tanker drivers delivering heating oil to my house) to other industries. Some of these other industries are ones that I think could help in a transition to a lower fossil fuel energy world.
So I probably have not cut any fat, only redistributed it - that was until my job was outsourced just before I turned 60
and so I have had to cut a lot of fat to last until I get my pension.