Some quick, back-of-the-envelope-math, suggests the total energy used amounts to about 1'389 mAh (roughly 5 Coulombs, based on an article saying it transfers about 1 nanoampere of current per ring and rung about 10 billion times since it was completed).
Watthours and Joules is difficult to know without measuring the voltage on the device, which would also have to involve the change in voltage over time to get a more accurate number. I'm probably wide off once you account for the reduced power over time.
Watthours and Joules is difficult to know without measuring the voltage on the device, which would also have to involve the change in voltage over time to get a more accurate number. I'm probably wide off once you account for the reduced power over time.