A WATT is not energy, but just how fast you are using energy. A 100 WATT light bulb uses energy twice as fast as a 50 WATT light bulb. This is why it gives more light. Energy is work x time. Remember that the key word is time.
Work is the consumption of energy.
Energy is what you pay for. The amount of energy in a voltage spike is what does the real damage and the amount of energy a protection device can absorb is the real measure of its worth. Energy is watts x time. The amount of energy a surge protector can absorb without damage is a fixed value determined by the size of the parts the designer specified into the surge protector when he designed it. Restating what we've learned.