1889

Quotes from Nikola Tesla:

First, who was Nikola Tesla?

http://en.wikipedia.org/wiki/Radiant_energy
"...Radiant energy is energy that is transported by waves. This includes energy transception in the form of waves through space or various media. Radiant energy is also energy transfered through electromagnetic waves. Solar Energy is a type of radiant energy. Radiant energy may be calculated by integrating radiant power with respect to time. Radiant energy is usually expressed in joules...."

 http://www.whatmatters.nu/ferw.html
Nikola Tesla worked out of the conviction that, in his own words, the “new power for the driving of the world's machinery will be derived from the energy that operates the universe, the cosmic energy, whose central source for the earth is the sun and which is everywhere present in unlimited quantities.”