It's not just about energy per se, but value, or "utility", let's say measured at a constant market price in an arbitrary currency. Why don't you agree with this view?
Value or utility? And how do you measure utility at a market price?
There are lots of ways economists do it. Look at people's behavior in choosing between options that have a currency value (observed or estimated), and then make inferences.
The point is that non-economists tend to think in terms of discrete, tangible things such as "the Earth" and "methane hydrate extraction", whereas economists tend to think in terms of numbers and equations. The economist's viewpoint is that he or she is thinking at a higher level because he or she is at once being more
general and
precise than someone talking about peak oil or the need to recycle.
