Your response should contain at least 200 words. Your answer must contain a title, wrapped in double angular brackets, such as <<poem of joy>>. Highlight at least 2 sections in your answer with markdown, i.e. *highlighted section*. Include keywords [environment, sustainability, renewable energy] in the response. At the end of your response, please explicitly add a postscript starting with P.S. Answer the following question: What are the main challenges and solutions in promoting renewable energy for a sustainable environment?
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