What is Power
Man himself is a very complex engine, converting the chemical energy contained in the food he eats into various other forms of energy. He does this quite efficiently, but is nevertheless not a very powerful machine. To build any of the ancient wonders of the world, such as the pyramids of Giza in Egypt, required enormous numbers of slaves, who toiled for many years to pull the huge slabs of rock up sand slopes piled against the sides of their buildings. Modern building machines could, no doubt, have finished the job in a fraction of the time, but in doing so would not have produced any more energy. The difference lies in the power of the machine used.
Power measures the amount of work a machine can produce in a given time. Modern machines are 'powerful' because they can give out large amounts of energy per second. This does not necessarily mean they are more efficient.
In fact the very powerful motors of a launching rocket require enormous supplies of fuel to put quite a small satellite into orbit around the earth. They are, therefore, very inefficient.