Over 100 years ago, scientists believed that man needed to discover ways to produce renewable energy.  They soon began to turn their focus to solar energy.  Through the progression of technology, solar energy is now a common source of energy.  Solar energy is the harnessing of energy from the sun in the form of heat (also known as thermal energy) and light. Solar energy converted to thermal energy is used to heat water and spaces for uses in commercial and residential buildings, greenhouses and swimming pools.  Buildings are constructed so as to utilize the light and heat radiating from the sun.  

Solar energy is also converted to electricity by two methods.  One is the use of solar cells, which are used to power items like calculators and watches.  The other method is solar power plants that produce electricity from thermal energy.  The energy collected is then used to heat a liquid, converting it to steam that powers a generator.  A shortcoming of this method is that the sun does not shine consistently in any given location on the earth.  Weather conditions also play a major role.

Interestingly enough, attention to solar energy was renewed in the early 1970's due to the oil crisis because there was concern that oil resources were dwindling.  Today's energy concerns have pushed industries to aggressively seek alternative solutions.  Former Vice President Al Gore is a strong proponent of solar energy.  While there are those who do not share his enthusiasm and vision, it seems that fully utilizing the sun's energy would be a viable solution to the energy problem.