RE: Those that are serious about clean power have one choice: Nuclear.
What do we do with the radioactive waste material?
Check these Ted talks out:
https://www.youtube.com/watch?v=ciStnd9Y2ak
https://www.youtube.com/watch?v=oTKl5X72NIc
Extra credit:
https://www.youtube.com/watch?v=LZXUR4z2P9w
Most of it can and should be recycled and reused. Jimmy Carter (blast his eyes) forbid doing so by executive order; no President since then has had the guts to rescind his order.