Nano Engineered Solar panels

Ray Kurzweil was saying on his documentary called, "Transcendental Man" that within 20 years it will be possible for nano engineered Solar panels to replace ALL oil based energy on earth. However, since he has been right about so many other exponential technology things like knowing about the internet 20 years before it happened and knowing the year the Soviet Union would collapse etc. likely he will be right about nano engineered solar panels taking over world energy needs. He says the cost per Watt within 20 years will be less than any other known technology at present.

Since I believe that Solar cells may be the only "Safe" form of energy to use on earth in regard to harming the Magnetosphere or depleting oil reserves or water depletion from burning hydrogen and oxygen and other types of problems I am very hopeful of hearing this.

Wind power might also be considered safe if it wasn't generated using magnetic field breaking technology. This is my thought as an intuitive who is interested in science.