The sun is probably the most important source of renewable energy available today.
Sunlight, or solar energy,
can be used directly for heating and lighting homes and other
buildings, for generating electricity, and for hot water heating, solar
cooling, and a variety of commercial and industrial uses.
The sun's heat also drives the winds, whose energy,
is captured with wind turbines. Then, the winds and the sun's heat
cause water to evaporate. When this water vapor turns into rain or snow
and flows downhill into rivers or streams, its energy can be captured
using hydroelectric power.
Along with the rain and snow, sunlight causes plants to grow. The
organic matter that makes up those plants is known as biomass. Biomass
can be used to produce electricity, transportation fuels, or chemicals.
The use of biomass for any of these purposes is called bioenergy.