Tesla conceded that his World Power System project was "retarded by laws of nature. The world was not prepared for it. It was too far ahead of time. But the same laws will prevail in the end and make it a triumphal success."
Perhaps the the world is now prepared for this technology as small applications using Tesla's discoveries are finally being revealed to the public.
In a 1900 magazine article, The Problem of Increasing Human Energy, Tesla discusses a machine that can gather heat from the ambient air and other forms of harvesting energy from the natural world.