Why is the future of solar energy bright?

Question

1. Every year, solar cells are becoming cheaper and better. Solar energy is also clean and it will never run out.

2. Because every year, solar cells are becoming cheaper and better, solar energy is also clean, and it will never run out.

3. Because every year solar cells are becoming cheaper and better, solar energy is also clean and it will never run out.

(Which one is a suitable answer to the question? Would you like to look at the sentences and punctuation marks? Which one is best and would you let me know better answers containing the same content?)

Answer 1

I think #1 is best. There is at least one punctuation error in #2, and most sentences that begin with "Because" are awkward (and sometimes incorrect).