Why alkanes produce more energy on combustion?

The energy produced by burning a hydrocarbon comes from breaking both carbon-hydrogen and carbon-carbon bonds and recombining them into carbon-oxygen and hydrogen-oxygen bonds. Because an unsaturated hydrocarbon has fewer hydrogen carbon bonds, it has less hydrogen per molecule than a similar unsaturated hydrocarbon and will produce more carbon dioxide. This also means unsaturated hydrocarbons produce less energy when burned than do saturated hydrocarbons.
Thanks

Hi
Alkanes produce more energy on combustion because it has better H/C ratio.
Higher this ratio better fuel it is.
Thanks & Regards, Arun Kumar, Btech,IIT Delhi, Askiitians Faculty