1. Energy left over from the original accretion of the planet and
augm ented by heat from rad ioactive d ecay seeps out slowly
everywhere, everyd ay. In certain areas the geotherm al grad ient
(increase in tem perature with d epth) is high enough to exploit to
generate electricity. This possibility is lim ited to a few locations on
Earth and m any technical problem s exist that lim it its utility. Another
form of geotherm al energy is Earth energy, a result of the heat storage
in the Earth's surface. Soil everywhere tend s to stay at a relatively
constant tem perature, the yearly average, and can be used with heat
pum ps to heat a build ing in winter and cool a build ing in sum m er. This
form of energy can lessen the need for other power to m aintain
com fortable tem peratures in build ings, but cannot be used to prod uce
electricity.
2. WIND Energy from
the wind.
Why is energy
from the wind
renewable?
3. The m ovem ent of the atm osphere is
d riven by d ifferences of tem perature at the
Earth's surface d ue to varying
tem peratures of the Earth's surface when
lit by sunlight. Wind energy can be used to
pum p water or generate electricity, but
requires extensive areal coverage to
prod uce significant am ounts of energy.
4. BIOMASS
Energy from
burning organic
or living matter.
Why is energy
from biomass
renewable?
5. BIOMA SS the term for energy from plants. Energy
is
in this form is very com m only used throughout the
world . U nfortunately the m ost popular is the burning
of trees for cooking and warm th. This process releases
copious am ounts of carbon d ioxid e gases into the
atm osphere and is a m ajor contributor to unhealthy air
in m any areas. Som e of the m ore m od ern form s of
biom ass energy are m ethane generation and
prod uction of alcohol for autom obile fuel and fueling
electric power plants.
6. WATER or HYDROELECTRIC
Energy from the
flow of water.
Why is energy of
flowing water
renewable?
7. L ike the wind s, flowing water is a prod uct of the
earth ´s clim ate and geography. Snowm elt and
runoff from precipitation at higher elevations
flow toward sea level in stream s and rivers. In
an earlier era, water wheels used the power of
flowing water to turn grind ing stones and to run
m echanical equipm ent. M od ern hyd ro-turbines
use water power to generate hyd roelectricity.
8. SUMMARY
What are the
differences
between
nonrenewable and
renewable
resources?
9. Renewable resources are those that are
replaced in nature at a rate close to their rate
of use. Non renewable resources exist in
fixed amounts or are used up faster than
they can be replaced in nature.
