What is "easy power"? It is the ability, through proper technique, to generate great force in your shots, whether it's looping or smashing. Given a high ball and enough time, most players beyond the beginning stage can hit the ball pretty hard. But often they strain to do so, which costs them both power and consistency. Players with good technique can do the same without straining, and end up with more power and consistency. Most of us have seen such players, who seem able to generate point-ending power (both speed and spin) with ease while others strain to do so. What is their secret?
It's all about timing and using the whole body. Most players, when hitting or looping hard, strain to add power, and the result is they get nearly 100% force from only a few muscles, from the upper body and arms. They are losing the power from the lower body, from the legs and waist. (Some may use waist, but without the legs you can't really use the waist muscles effectively.)
Watch videos of top players as they rip forehands, and see how they almost rock into the ball as they rotate into the ball, smoothly putting their entire body into the shot. They aren't even using 100% power from any of these muscles, because to do so would mean to basically jerk one muscle at full power, and so you only get power from that one muscle - and you can't really control a muscle that contracts at 100%. Instead, use all the muscles, but at perhaps 70%. This allows you to use them all in smooth progression, from legs to arm. When you can do this, you too will have "easy power" - and both your power and consistency will shoot up.
Here are two videos of Wang Liqin (three-time world men's singles champion) that illustrate this. He is considered by many to have had the best forehand loop of all time. Here's video of him looping in a drill (45 sec, including slow motion), where you can see how he rotates all of his body into the shot, starting with the legs and moving up to the arm. Here's video of him (9sec, also slow motion replay) ripping a winner.