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Energy
generation
and useMR. BANKS
7TH GRADE SCIENCE
Worldwide energy use
As the world becomes
more populated and
technologically
advanced, the demand
for energy has increased.
Before electricity was
discovered, worldwide
energy use was around
20 x 1015 Btu, basically all
of which for heating.
Worldwide energy use
Energy use is divided into three
main categories
Heating
Transportation
Electricity
Heating
The earliest form of energy
use.
Buildings, vehicles, food,
water, industry.
Whenever something is
heated energy must be
used.
Transportation
Transportation is one of the
biggest uses of energy today.
Our world works based on the
idea that we can easily
transport things long distances,
including transporting ourselves.
Electricity
Incredibly useful for doing work.
Can be stored for later use.
Makes modern life possible.
Used in an ever increasing
portion of our lives.
Renewable vs
nonrenewable energy Renewable energy: an energy
source that can be replenished
within about a century.
Never run out or can be
regrown
Nonrenewable energy: an
energy source that can take
millions of years to replace, if
they can be replaced at all.
Can’t be replaced in a time
frame that matters to humans.
Fossil fuels
Includes coal, oil, natural gas,
and gasoline.
Provides 85% of the world’s
energy.
Formed from the remains of
prehistoric plants and animals.
Getting fossil fuels
Coal – Must be mined from
where it was formed
underground.
Oil and natural gas – Easier to
extract than coal, it just has to
be pumped to the surface.
Advantages of fossil
fuels Large amounts of electricity can
be generated relatively
cheaply.
Transporting oil and natural gas
is easy.
Large amounts of energy are
stored in a small amount of
fuel.
Disadvantages of fossil
fuelsProduces pollution
Carbon dioxide, a
greenhouse gas, thought to
be the major force behind
global warming.
Sulfur dioxide, leads to acid
rain.
Oil spills
Coal mining is dangerous,
and strip mining destroys the
environment.
Disadvantages of fossil
fuels They are NOT renewable
resources.
It takes millions of years to form
new fossil fuels.
Our consumption of fossil fuels
has doubled every 20 years
since the year 1900.
Disadvantages of fossil
fuels It is not a question of if we run out of fossil fuels, but
when.
Most projections leave us with about 100 years of fuel
left.
Disadvantages of fossil
fuels This is particularly bad in terms
of oil since we use it to make
plastics, wax, grease, asphalt,
and many other products.
Nuclear power
Nuclear power: using nuclear
fission from radioactive
materials to generate heat
and thus electricity.
Usually uranium or plutonium,
sometimes thorium.
Advantages of nuclear
power Very cheap to produce
power.
Very little pollution, very
little waste.
Lots of energy for very little
fuel.
Reliable power.
Disadvantages of
nuclear power Dangerous waste
Though not much waste is
produced, it is incredibly
deadly.
Not renewable
Once we dig up all the
uranium there will never be
any more.
Disadvantages of
nuclear power Meltdown
When a nuclear power
plant has problems, it can
be incredibly damaging to
people and the
environment.
Thankfully this is a rare
occurrence and is usually
contained.
Disadvantages of
nuclear power Chernobyl
The worst nuclear accident in history.
Happened in 1986 in the Ukraine, then controlled by Soviet Russia.
Everyone living within 20 miles of the plant were evacuated and most not allowed to return, about 350,000 people total.
Parts will be dangerous for more than 10,000 years.
Solar power
Solar power: Solar Cells,
called “photovoltaic" or
"photoelectric" cells convert
light directly into electricity.
In the sun, a one meter
square can power two 90
watt light bulbs.
Solar power
Solar furnace, a huge array
of mirrors to concentrate the
Sun's energy into a small
space and produce very
high temperatures to
generate electricity.
Advantages of solar
power The fuel, sunlight, is free and renewable!
Especially useful for low power objects like small
lights and battery chargers.
Produces no waste.
Disadvantages of solar
power Doesn’t work at night or when
it’s cloudy.
Need a battery backup or other
power sources.
Can be unreliable, no power
when it’s cloudy.
Expensive to build solar power
stations compared to other
power plants.
Wind power
Wind power: Wind blows and
turns the blades of a windmill
to generate electricity.
Before electricity, wind was
used to do work in other
ways.
Advantages of wind
power The fuel, wind, is free and
renewable!
Produces no waste.
The land beneath can still be
used for farming.
Works at night.
Disadvantages of wind
power Wind is unpredictable and some
days there may be none.
Need a battery backup or other
power sources.
Can kill birds and bats.
Kind of noisy, with a constant
“swooshing” sound day and
night.
Some people don’t like the look
of them.
Hydroelectricity
Hydroelectricity: A dam is built
to trap water from a river. Water
is allowed through tunnels in the
dam to generate electricity.
Advantages of
hydroelectricity The fuel, water, is free and
renewable!
No waste is produced.
More reliable than wind or
solar.
Power generation can be
regulated to meet
demand.
Can be used to store
drinking water.
Disadvantages of
hydroelectricity Dams are expensive to build.
Damming rivers floods large
areas upstream.
Can effect water quality in
an area.
Can effect fish migration
and reproduction.
Biomass
Biomass: Plant and animal products and wastes (trash,
manure, woodchips, corn, cornstalks) and turn them
into fuels like methane and natural gas.
These can then be used to generate electricity or heat.
Advantages of
biomass The fuel is waste, so it makes
sense to use it. It is also very
cheap because of this.
It is renewable, we’ll never run out
of food waste.
Results in less demand on
earth’s resources.
Disadvantages of
biomass Collecting enough waste can
be difficult.
Some wastes aren’t available all
year.
The fuel is burned, so it
contributes carbon dioxide
Can lead to increased food
prices.
Geothermal power
Geothermal power: Hot rocks underground
heat water and produce steam which is used
for electricity generation and heating.
Advantages of
geothermal power The fuel is simply underground
water, so it’s free and
renewable.
Once the power plant is built
the energy is basically
free.
No pollution or waste.
Disadvantages of
geothermal power There are only a few places you
can build geothermal power
plants.
Sometimes geothermal power
sites can “run out of steam”
They generally build back up
after a few years.
Energy use worldwide
American energy use
American energy use
Energy use in Arkansas
Energy use in Arkansas
Electricity
