Earlier made hydro generators went from a 90% to a 40% fish fatality rate. This still drove concern about the wisdom of Hydro power. Recently cities like Boulder, Colorado and Little Rock, Arkansas have been upgrading their hydro generator systems. What is behind the rethink of hydro generation? Rising fossil fuels and global warming concerns are pushing us to reexamining older paradigms. New hydro generation systems are going to the new innovative screw shaped design that boasts of only a 1% fish fatality rate. The new designed systems have seen 7% to 28% increases in electricity generation over older systems. Now we can retool the older hydro dams to increased efficiency with little impact to the fish populations.