In a stock pot, add beer, Worcestershire sauce, hot sauce and garlic powder and bring to a boil.
Add sliced onions to the beer mixture and allow to simmer for 2-3 minutes.
Then, add bratwursts. For a fast cook, bring to a boil, and cook for 12 minutes. For a slower cook, allow to simmer for about 20 minutes.
(Optional) To caramelize the outside of the bratwurst, carefully remove from the pot with tongs. Add the brats to a greased baking sheet and carefully prick with a fork to keep the bratwurst from exploding in the oven. Broil the bratwursts on high for 2-3 minutes.
You can return the brats to the beer solution on low or no heat to keep them warm before serving.
For the red pepper relish, add olive oil to small skillet and heat over medium-high heat. Add red peppers and onions, sauté for 5 minutes. Add garlic and vinegar, then reduce heat to low. Stir well and allow to cook down for an additional 5 minutes, until vegetables are soft.
Assemble the brats on a bun with a hearty scoop of the red pepper relish and mustard (optional). Serve warm.