From what I have heard from my energy business acquaintances, the only alternative source that has a hope of surpassing fossil is nuclear. Solar panels and wind have their own issues: rare earth minerals, difficult upkeep, and in the case of the non-mirror solar- toxic pollution as they breakdown. I hope some combination of nuclear, geothermal, hydro, mirror-solar, and wind can combine to satisfy energy needs, but I am not optimistic.