How is mechanical energy measured?

I am simplifying the question. Apparently my language was unclear the first time. "Tony I" claimed healing energy has been measured but obviously didn't see my question the first time since he didn't answer. Two important components of this...

It is well known that nuclear energy ranks #1 when measured simply by deaths (see for example How does nuclear energy compare to other sources of energy in deaths per kWh?). However, such studies appear to equate the accidental death of a 28-year-old...

How would I measure mass in relation to energy. For example in e=mc2, how would the measurement of energy stated if mass was equal to 1 kg? And how would it be stated if it was 1 gram. Saying e=1xc2 wouldn't really tell me what E equals. To be honest...

If Joules are the basic unit of energy, how do we measure the energy output of such disparate processes and objects as the sun, photosynthesis, fermentation, the metabolism of hummingbirds, power plants, cars, etc. etc.?

More specifically, there is a power cable connecting a distant substation to a distant consumer. Only one conductor is used. The circuit is completed through the ground. I only have access to this one conductor. Is it possible to measure the amount of...

Is it measured in calories? or maybe btu? i cannot find anything on the internet about the AES system. any help is appreciated.

1. Who measured it? 2. What equipment was used, and what were the units of measure? 3. What process was used to measure it?