What are the main types of renewable energy sources and how do they work? Your response should contain at least 5 sentences and at least 2 placeholders represented by square brackets, such as [address]. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. Include keywords [solar, wind, hydro, geothermal, biomass] in the response. In your response, the word *renewable* should appear at least 2 times.

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