ABSTRACT
The energy available for use on Earth has two sources — solar and nuclear. The Sun’s energy is generated by nuclear fusion of hydrogen into helium during which some mass M is lost to produce energy E, according to Albert Einstein’s famous formula E = MC2 where C is the speed of light in a vacuum. Thus, it could be argued that the only source of energy is nuclear. So how is the solar energy reaching Earth used, stored, or lost? That is the subject of this chapter.
