In meditation it feels like energy is generated from within.In some chi kung you can breath energy in from the outside if your body is open for it. Thougts is energy,and mind is a thought machine,generating thoughts all the time.When we slow down or stop this all this thoughts,is the mind still working?instead of producing thoughts it is just genarating prana? any ideas?
actually thoughts are a big waste of energy. . during meditation we gently introduce a new habit for the mind ie to go back to the mantra whenever we lose it...so yes for the time being the mind is still working ...with practice the inner silence grows..and one realizes that he or she IS NOT the mind....the mind is naturally dropped (it never existed) to go into the vastness of the Self...
I agree it's energy efficiency (preventing waste) rather than energy production. Part of it is saved on thinking, part of it on deeper mental blockages that were subconscious but took a lot of effort/straining/mental clenching nevertheless.
The energy is always there, more a question of whether you notice it or not. Meditation quiets the mind, making it easier to notice. Here is a good thread related to this topic that you might find interesting.