Very interesting thoughts Mael; and it is very good to see
you once again on this forum!
Aye, there is an abundance of freely available energy
which can be fairly easily harnessed when one learns
how to do it. One of my favorites is the use of waste
such as cattle dung, human dung and vegetable waste
to produce methane gas. Another is the fermentation of
grains/fruits to produce alcohol. For use as a fuel in
gasoline engines the alcohol only needs to be only 50%
or greater (about 70% seems ideal.) The water content
serves as a convenient form of water injection which
increases efficiency.
Most of the best processes are old and go back
hundreds of years but have come into a state of
dis-use as a consequence of big oil. When the
sh*t hits the fan in the very near future the old
knowledge will be a valuable commodity.