Heat the oven to 200 C / 400 F. Line a 33 x 46 cm / 13 x 18 inch sheet pan with foil.
Snap the woody ends off each asparagus spear by bending it near the bottom until it breaks naturally.
Toss the asparagus spears in a mixing bowl with the olive oil, garlic powder, and black pepper until coated.
Divide the asparagus into 8 bundles of 3 spears each.
Wrap one slice of bacon around each bundle in a spiral, stretching it slightly so it clings tight, and place seam-side down on the pan.
Space the bundles at least 1 inch apart on the pan so the bacon crisps instead of steaming.
Bake for 20 to 25 minutes, flipping the bundles halfway through, until the bacon is crisp and browned and the asparagus tips are tender.
Broil for 1 to 2 minutes at the end if the bacon needs more color, watching closely so it doesn't burn.
Let the bundles rest on the pan for 3 minutes, then sprinkle with red pepper flakes and serve with lemon wedges.