Actually, you do want something from nothing.
Wattage = Voltage * Current
Wattage always stays the same (it's the conservation of energy). You can ever get more wattage than what you started with. From that equation, you can decrease current to increase voltage, or you can decrease voltage to increase current. You can never increase both because if you do, wattage will change.
It's like making cookies from a bunch of dough (power). The size of the cookies is like the voltage, and the number of cookies is like the current. You can either make a million tiny cookies from that same dough, or you can make one really big cookie. But you can't make a million really big cookies from that dough because you only have so much. The only way to make more larger cookies is to add more dough.
You are mistaking current and voltage for wattage and voltage. The only thing you can do is add on more batteries (power) at the start. Hooking the batteries in parallell will increase the power by increasing the current. Hooking up the batteries in series will increase the power by increasing the voltage.