The amount of energy that enters the earth’s atmosphere every year through solar radiation is greater than the total energy locked within all of the oil and coal that can be found on earth.
The sun’s radiance is continuously renewed by what seems to be an inexhaustible supply of fuel. Yet, at any given moment in time, the earth has only 8 1/2 minutes of solar energy that we can be certain of—that is the time it takes for light to travel from the sun to the earth. If the sun were to mysteriously go dark within an instant, ceasing to radiate its energy, the earth would have 8 1/2 minutes of light and heat before total darkness and the beginning of an unending winter, where global temperatures would soon drop below minus 100 degrees Fahrenheit.
The temperature of outer space, without the warmth of the sun, is minus 454 degrees Fahrenheit.
Fortunately, the sun is a giant nuclear reactor, and there is enough fuel within the core of the sun to sustain its nuclear reactions for longer than humans need to worry about.
With the exception of the ocean tides—which are caused by the gravitational pull of the moon as it orbits the earth—all renewable energy on earth is sustained by nuclear reactions: atomic fusion within the sun and atomic fission within the core of the earth; yes, the earth too is a giant natural nuclear reactor.
Renewable energy is renewable because nuclear energy is sustainable for a period of time that is longer than humans need to worry about. Therefore, any energy source that is sustainable for a period of time that is longer than humans need to worry about can be considered Renewable.
In our pursuit of renewable energy, let us not turn our backs on the promise of man-made nuclear energy here on earth.