SCIENCE■ Percentage of current energy use Less than
1 percent ■ Reserves left UnlimitedAlmost all the energy on Earth originally
comes from the Sun. We can tap the Sun’s
energy directly to make electricity. Solar
panels like these turn sunlight into
electricity.Solar energy
Energy made from the Sun’s light or heatHydroelectric power
Energy from moving rivers and seas■ Percentage of current energy use 4 percent
■ Reserves left UnlimitedGrowing plants and animals store
energy we can use in the future. We
can grow crops to make oil or make
electricity by burning animal waste
such as chicken manure. Energy made
this way is called biofuel.Biofuels
Energy made using living plants and animals■ Percentage of current energy use Less than
1 percent ■ Reserves left Unlimited
Deep inside, Earth is hot molten rock.
Some of this heat is released when
volcanoes erupt. Geothermal energy
means using Earth’s inner heat to
generate hot water and electricity.
Geothermal power
Energy from Earth’s internal heat
Wind power
Energy from air currents moving across Earth■ Percentage of current energy use Less than
1 percent ■ Reserves left Unlimited
Wind moving over the oceans stores
energy in waves. Waves have kinetic
energy (because they move) and
potential energy (because they’re
above the normal sea surface). We can
use the energy in breaking waves and
shifting tides to generate electricity.
Wave power
Energy from the oceans and tides
Nuclear power
Energy made from
atomic reactionsd TURBINES (water wheels)
behind these channels generate
electricity when water flows past them.■ Percentage of current energy use 6 percent
■ Reserves left UnlimitedRivers flow from mountains and hills
down to the sea. This means they
release stored potential energy.
Hydroelectric power plants capture
this energy to make electricity.■ Percentage of current
energy use 6 percent
■ Reserves left Raw uranium,
80 yearsAtoms are made of tiny
particles held together
by energy. Large atoms
can release this energy by splitting
apart. Small atoms can release
energy by joining together.
Most nuclear power
plants make electricity
by splitting apart
large uranium
atoms.■ Percentage of current energy use Less than
1 percent ■ Reserves left UnlimitedWind turbines work like propellers
in reverse. As their rotors spin in the
wind, they turn small generators
inside and make electricity.■ Percentage of current
energy use Oil 38 percent, coal
25 percent, gas 23 percent
■ Reserves left Oil 40 years,
gas 100 years, coal 250 yearsAlthough bad for the
environment, fossil fuels
are still the world’s main
energy source. Coal is
cheap for making
electricity, gas is
easy to pipe to
homes, and oil is
convenient for
powering vehicles.Fossil fuels
Energy from coal, oil, and gasENERGY SOURCES
Most of the energy people now
use (80-90 percent) comes
from fossil fuels. The rest
comes from renewable energy
and nuclear power.
ENERGY(c) 2012 Dorling Kindersley. All Rights Reserved.(c) 2012 Dorling Kindersley. All Rights Reserved.