How "powerful" you are refers to your ability to generate force quickly. Sprinters, Olympic lifters, and football players are all power-based athletes. Contrary to their name, a "power lifter" does not exhibit much power, rather they produce a lot of FORCE, and should probably be called strength lifters or force lifters (cue Star Wars joke).
Simply put. power requires speed, so while grinding through a heavy lift will make you stronger, it won't increase your power. Instead, we want to use lower weight/resistance and lift as quickly as possible. Since power training requires intense bursts of energy, it is often not recommended for beginners, however, it can be performed safely by beginners if the intensity and exercise selection is appropriate. As a general rule, start slow and build up speed and resistance.
INTENSITY: The optimal load for power training is still going to be heavy, at somewhere between 80-90% of your 1RM of a single effort, or 30-85% for repeated efforts.
REPETITIONS: The repetition range for Power training should be relatively low, at 1-2r for heavier loads and 3-6r for lighter loads.
SETS: Beginners will benefit from only 1-3 sets of power training while intermediate and advanced lifters can perform up to 6 sets.
FREQUENCY: I recommend 2-3 sessions of power training per week, however, plan to vary the intensity with a heavy power session and a lighter power session.
RECOVERY: If you are getting tired, you are no longer training for speed. Take your time between sets/reps.
Don't forget... the goal is speed. Put 100% into each lift and become a more powerful athlete.
B.Kin, Canadian Society of Exercise Physiology CPT