Framtiden

"And what will they burn instead of coal?"
"Water," replied Harding.
"Water!" cried Pencroft, "water as fuel for steamers and engines! water
to heat water!"
"Yes, but water decomposed into its primitive elements," replied Cyrus
Harding, "and decomposed doubtless, by electricity, which will then have
become a powerful and manageable force, for all great discoveries, by some
inexplicable laws, appear to agree and become complete at the same time.
Yes, my friends, I believe that water will one day be employed as fuel,
that hydrogen and oxygen which constitute it, used singly or together, will
furnish an inexhaustible source of heat and light, of an intensity of which
coal is not capable. Some day the coalrooms of steamers and the tenders of
locomotives will, instead of coal, be stored with these two condensed
gases, which will burn in the furnaces with enormous calorific power. There
is, therefore, nothing to fear. As long as the earth is inhabited it will
supply the wants of its inhabitants, and there will be no want of either
light or heat as long as the productions of the vegetable, mineral or
animal kingdoms do not fail us. I believe, then, that when the deposits of
coal are exhausted we shall heat and warm ourselves with water. Water will
be the coal of the future."
"I should like to see that," observed the sailor.

Jules Verne in Mysterious Island 1874