William started his knol with a brief history on solar energy as one of alternative energies today.

Here’s an interesting fact that I found in William’s knol about the use of solar energy:

In 2004, solar energy accounted for only 0.039 percent of the world’s total primary energy supply of 11,059 million metric tons of oil equivalent, according to the International Energy Agency. In other words, solar energy provided about 4 terawatt-hours of electricity generation, out of an estimated overall total production of some 17,450 terawatt-hours (1 terawatt = 1 trillion watts).

Considering the abundance of sun’s exposure on earth surface, the 0.039 percent, in my opinion, is very insignificant, thus there are definitely rooms to grow for solar system implementations and usages.

Some of the uses of solar energy today can be found in the form of passive solar and solar water heating.

Passive solar is the use of techniques and technologies for the purpose of daylighting, to supplement or replace electric lighting.

Regarding the solar water heating, William explained that today, solar water heaters are rapidly returning to the mainstream. In June, Hawaii enacted a law that requires all new homes to be built with solar water heaters, which will save the state an enormous amount of energy every year.

If you would like to learn more, please visit William Pentland’s knol on solar energy.

Image by futureatlas.com.