Charged objects create electric fields in much the same way that magnet poles create magnetic fields. To produce a very high voltage, rub a balloon on your head, or scuff your shoes upon the floor when the humidity is very low. Electric fields can push or pull upon electric charges, so electric forces are caused by voltage. In a battery circuit, the voltage from the battery causes the charges of the wire to flow. Another answer here .
Energy is measured in Joules, and when energy flows, the flow is measured in Joules per second.
Power is a FLOW RATE of energy, or a RATE OF USE of energy. We can store electrical energy, but electric power is not something that is ever stored. A spark is a volume of air which has been electrically converted from a gas into a plasma, the fourth state of matter. While plasma can be created by high temperatures, it can also be created electrically. Sparks are made of glowing air, and the color of the spark depends on the type of gases involved.