can wattage can be increased?

[Digix]

power can be increased in expense of duty ratio.
you can charge capacitor using 1W for 1minute and discharge it using 60w during 1 sec.
or even 10kW if you discharge if you discharge it during 1ms like it is done in photo flash lapms.

however total energy will newer change

[mylogin]

Transformer is rated by VA, or KVA.  a 12VA transformer has output of 12V can supply max. of 1A of current.  if overloaded( ex. 1.5A of current) the voltage will drop.  the energy of the transformer can supply is limited by the VA rating. you can calculate how much current the other side of the transformer should be by dividing the VA by the voltage input. so if your primary input is 110V the input current should be at least 12/110 Amp.  I your question you use the transformer to step up the voltage (12v/6A to 110v) the 110V side current will be max. (12x6)/110 Amp.  the total energy it can transform is the same.   it will not amplify the energy.   Same as your Wattage increase question.