Windmills Must Be the Future Source of Power

By Lord Kelvin

Philadelphia North American, May 18, 1902.

[NOTE: This article is part of a larger article -- reproduced in whole on a Nikola Tesla site -- which contains an introductory overview of Kelvin's article; the article itself, with the note: "The only article written by Lord Kelvin during his recent visit to the United States"; a short biography of Kelvin; and responses by Tesla, Prof. S. P. Langley, Thomas Edison, and Rear Admiral R. B. Bradford.]

To predict that the world's industrial progress will one day be halted and then rolled back in primitive methods is not a very daring prophecy when the conditions are studied closely.

Coal is king of the industrial world. The king's reign is limited. Sooner or later, it has been estimated that the world's supply of coal will have been exhausted. The commission appointed to inquire into the all-important matter in Great Britain has even said that a few hundred years at the outside will see the last basket of coal taken from the mines of England. In other quarters the supply is rapidly diminishing.

The enormous amount of coal required to run our great ocean steamships, our leviathans of the deep, and the innumerable factories of our cities is making such inroads upon the available store that nature cannot forever supply the demand. When all the coal of the earth is used, what then?

Perplexed humanity confronted with the possibility of its industrial machinery being stopped for want of power, will be forced to turn from earth to air. In the world there is to be found a force that has stood man in good stead from time immemorial. Long before the days of the steam engine or the ocean liners, ships were wafted from shore to shore by means of the force that lurks in the air. The time will come, unless man's ingenuity devises some means of replacing the exhausted coal supply with a fuel that will be equally efficacious - when the swift steaming greyhounds of the oceans will be dry-docked and their vitals torn out. Then the lightened ships will be fitted with the masts and sails of the old sailing days, and once more the seas will be dotted with vessels propelled by the method that is at present in decline. The day upon which the last shovelful of coal is taken from the bowels of the earth will mark the passing of the magnificent battleship, the swift cruiser and the torpedo boat. The navies of the nations will perish in a day for want of life-giving fire in the furnace rooms. In their place will arise white-winged fleets depending alone on their sailing power, as in the days of Nelson; the question of which ocean liner can cut down time of the passage from New York to Liverpool will no longer interest voyagers, for the trip will depend, as of old, on the favorable winds and the sailing capacity of the ship.

On land the effect of the exhaustion of the coal supply will be even more marked than on sea. Every building could be supplied with its own windmill, to use the motive power that wanders where it listeth on its roof top to turn wheels that will lift its elevators, generate electricity for its machinery; pump its water supply and do all that coal now makes possible in the machine room; sails on our factories, sails on our mills and in our shipyards to catch the slightest breath that blows and turn it into a means of moving the wheels of progress; wind power utilized everywhere as the servant of man, free for every one, working silently as a great force while the world sleeps. Possibly the exhaustion of the coal supply of the earth may turn out to be something of a blessing when it is considered how difficult and dangerous it is to wrest from the ground the hidden resources of nature for use as fuel, and how natural and easy it is to make the power of wind do the work now done by coal.

Then, in the great land changes of the coalless age I see vast fields of vegetation planted especially to serve as fuel. Each agriculturist will have his own reservation where the family fuel will be grown; a new industry will be born - the cultivation of fuel.

Water power will be largely useful, but the power to be derived from this source is not very great. Niagara is a vast force to look at, but measured in the horsepower it is not so tremendous. The tides cannot furnish any power worth speaking of; firewood must do much more.