Preheat a gas grill to medium-high heat. (450-500 F)
Cut off the brown ends of the Brussel sprouts and remove any yellow outer leaves. Cut them in half. Season with salt, pepper, garlic powder (optional) and olive oil. Thread onto the skewers, 6 halves on each one.
Grill for 5 minutes on each side, turning once.
Transfer to a plate and drizzle with Balsamic reduction or Balsamic vinegar.