so technical terminology is often thought of as a shorthand, a way of gaining great depth and accuracy of meaning with economy of words. so when you go back in the passage saving energy means saving money could be one. so all you really have to do is look for anything that talks about saving money and or energy.
To be roguish is to be up to no good, which could mean being untrustworthy like a criminal or playful and mischievous. If someone gives you a roguish smile, ...
