Renewable and Alternative

Energy Sources

World Wide Energy Production

15.2%

alternative

84.8%

fossil

fuels

World-wide, with the

exception of coal, which

has known reserves that

will last a couple of

centuries, the known

reserves of oil are

expected to be exhausted

in your lifetime...

Clearly, alternative energy

sources are needed for

the future

Alternative Energy Sources

alternative energy – a

form of energy derived

from a natural source that

could replace the use of

fossil fuels.

renewable energy - any

natural resource that can

replenish itself over a

relatively short amount of

time (a human lifetime).

Alternative Energy Sources

We will look at:

Solar energy

Geothermal power

Hydroelectric

Tidal Power

Wind energy

Biomass and Biofuels

Alternative Energy Sources

Solar Energy

The Sun is free (nobody owns or controls it)

In principle, the amount of solar energy that

reaches the Earth’s surface could provide for

all human energy needs forever

Solar Energy

The distribution of solar energy over the

continental U.S. in watts per square meter

The desert regions of the southwest U.S.

receive the most sunlight

Clean Solar Energy

Solar energy is clean energy

It produces no hazardous solid, liquid or gas

wastes

It does not create water or air pollution

Largest Solar Plant in the World

http://america.aljazeera.com/articles/2014/2/13/largest-solar-plantintheworldopensinusasindustrygrows.html

Disadvantages

• Solar panels are

expensive.

• When it is cloudy or at

night there is not enough

light.

• Some people don’t like

the look of solar panels.

What is it?

• Solar power

uses energy

from the Sun.

• Solar panels

transfer the

Suns energy

to heat water.

Advantages

• The energy from the Sun

is free.

• The sun does not produce

greenhouse gases.

• The sun will always be

there during our lifetime.

Geothermal PowerMagma rising from the mantles brings unusually hot

material near the surface

Heat from the magma, in turn, heats any groundwater

This is the basis for generating geothermal energy

Geothermal Power

The steam and/or hot water is used

to create electricity or for heating

Geothermal Power Plants

Worldwide, there are now about 40 geothermal

power plants, especially in Japan, Mexico and

the Philippines

Note that

most

geothermal

power

plants are

built along

plate

tectonic

boundaries

Klamath Falls, OR

http://climatesolutions.org/news/oregon-town-uses-geothermal-energy-to-stay-warm

Disadvantages• There are not many places

where we can build

geothermal power

stations.

• Harmful gases and

minerals may occasionally

come up from the ground

below. These can be

• difficult to control.

What is it?• Rocks

under the

ground are

hot.

• Water can

be pumped

through

these hot

rocks and

warmed up.

Advantages

• Geothermal energy does

not produce greenhouse

gases.

• The energy source is

free and will not run out.

HydroelectricHydroelectric is a very clean, pollution-free,

renewable energy source

The water is not consumed, but rather simply

passes thru the generating equipment, and since

several dams may occur along the same river, the

water can be reused and reused

HydroelectricA cross-section of a typical hydroelectric dam

Water flows down the penstock, turns the

turbine blades which power the generators

HydroelectricWater use for generating hydroelectric power is

totally dependent on the available water (duh!!)

The Glen Canyon Dam in Utah is the classic

example of building too big of a dam for not

enough water

Disadvantages• The dam is expensive to

build.

• By building a dam, the

nearby area has to be flooded

and this could affect nearby

habitats.

• If it does not rain much we

may not have enough water

to turn the turbines.

What is it?

• Flowing

water is

used to turn

a turbine

which

generates

electricity.

Advantages• When the electricity is

generated, no greenhouse

gases are made.

• The water used is free.

• It is a renewable energy source.

Tidal Power

All large bodies of water, including the oceans

and large lakes, have tides

Tidal power captures the energy contained in

moving water mass due to tides

Tidal Power

Turbines can be place on the ocean floor, for

example at the entrance of a bay, where the

flowing water can turn the fan to generate

electricity

Tidal PowerAnother option is to use under water turbines,

which is like an underwater wind farm

This is currently being tested offshore of Scotland’s

Orkney Islands

The ebbing and surging tidal flows turn 100 foot

propellers, which each produce 1 megawatts of

electricity

Disadvantages• A dam to make the water

flow through the generators

might be needed.

• Plants and animals that live

nearby might get harmed

• The tides only happen twice

a day, so can only produce

electricity at that time.

What is it?

• Solar power

uses energy

from the

Sun.

• Solar panels

transfer the

Suns energy

to heat

water.Advantages

• Tides are free and will not

run out.

• No greenhouse gases are

produced.

• It is reliable because we

know exactly when the

tides happen.

The wind is free, commonly available and

can provide clean, pollution-free energy

Today’s wind-turbines are very high tech

Wind Energy

The numbers indicate the percentage of

1990 regional electricity demand that full

utilization of wind energy could meet

Clearly, the great plains have significant

wind energy potential

Wind Energy

It would take about 1000 one-million watt

windmills to equal the energy output of one

sizable fossil fuel power plant

Wind Energy Limitations

The windmills can

be noisy

And they are hard

on migrating birds

Disadvantages

• Lots of wind

turbines are needed

to produce enough

power.

• Turbines can only be

put in windy areas.

• It is not always

windy.

• Some people don’t

like the look of the

turbines.

What is it?

• Wind turbines

are used to

generate

electricity from

the wind.

• The wind turns

the large

blades and the

blades turn a

generator.

Advantages

• Wind is renewable.

• Wind is free.

• No greenhouse gases

are made.

• There are few safety

risks.

Biomass energy is derived

from organic matter

Stoves that burn wood are

the classic example

In fact, there had been a

20-25% increase in the use

of wood stoves over the

past several decades

Biomass Energy

Biofuels differ from other renewable energy sources,

such as wind, hydroelectric, geothermal and solar,

as they are primarily used in the transportation

sector and are derived from recently living matter,

both plant and animal

Biomass Fuels or Biofuels

Disadvantages

• Inefficient (only 30%

efficiency).

• Releases harmful

solid carbon

particles into the

atmosphere.

What is it?

• Biomass, is a

renewable

energy source

made of

biological

material from

living, or

recently living

organisms.

• Energy is

released by

combustion

(burning).

Advantages

• Produces less pollution

than fossil fuels.

• Does not cause acid

rain.

• Can be found locally.

• It is renewable.