The real something for nothing

[Spongebob]

There are other threads that ostensibly pretend to be about the issue of energy, but I want to open a thread where the science and technology are actually discussed intellectually, if that's possible.  Humans have gone through multiple energy sources and we've been straddling fossil fuels and nuclear fission mostly for over a century now and it's clearly taken a toll on the earth's climate and environment.  The scientific consensus is that if this continues unabated, the earth will become quite inhospitable to humans.  So, understandably, we've been tinkering with other forms of energy.  Wind, solar, geothermal, ocean, fusion, biomass, maybe some others I can't think of right now.  Energy appears to be increasing in demand given the rising population and technological development around the globe.  So what is the best case scenario going forward?  What are the pitfalls?  What are the hail mary's?  I'm interested in real thoughts about technology and our future.