Renewable

Energy:

Alternative Energy

Energy Part 3

I. Why do we need Alternative Energy?

• As of 2016, the most used energy sources in the US

were fossil fuels

• Below is a list of major energy sources and the total

percentage of electricity they generated in the US in

2016, according to the EIA

o Natural gas = 34%

o Coal = 30%

o Petroleum = 1%

o Nuclear = 20%

• The data shows that in 2016, fossil fuels and nuclear

energy generated 85% of the electricity in the US

Why is this large percentage alarming? Why is it potentially bad

that we rely so heavily on those energy sources?

• Recall, fossil fuels and nuclear energy are examples of

________________energy

o Pros = can be used anywhere, more reliable, produce

large amounts of energy

o Cons = limited supply, not environmentally friendly

They are all nonrenewable energy sources!

Nuclear Fossil Fuels

Pro: creates a lot of energy through

________ and ________________

Con: creates _________________,

hard to store waste, terrorism;

uranium and other atoms are finite

(they will eventually run out)

Pro: creates a lot of energy through

___________________

Con: limited supply, __________

(global warming)

nonrenewable

splitting combining atoms

radioactive waste

burning (combustion)

give off CO2

• With all of this being said, in terms of supply and environmental

friendliness, there is a push for alternative, renewable energy

sources

• Recall, __________ energy can be ___________________and

in our lifetime

o Pros = unlimited supply; “clean” energy

o Cons = dependent on climate/geography; can be costly to set-

up and maintain; hard to control how much energy is

produced at a given time

• There are many different sources of renewable energy; below is

a list of the common types and the percentage of US electricity

they generated in 2016

1. Water Energy = 6.5%

2. Wind Energy = 5.6%

3. Biofuel = 1.5%

4. Solar Energy = 0.9%

5. Geothermal = 0.4%

renewable replenished naturally

II. Water Energy

• Water energy, or ____________, is currently the most

utilized renewable energy source in the US.

• It utilizes the following energy conversions:

______________ ____________ ________________

_______________

How it works

• Hydro-electric plants utilize moving or falling water to do

work or in other words, create energy.

1. Water collects behind a dam in a reservoir; typically

placed on a river that has a large drop in elevation

(_________)

2. Water from the dam flows through the intake and into a

pipe called a penstock (_______)

hydropower

Potential Energy Kinetic Energy Mechanical Energy

Electrical Energy

potential

kinetic

3. The moving water pushes against blades in a turbine,

causing them to turn (____________)

4. The turbine spins a generator to produce electricity

(___________)

5. Power lines are connected to generator, carrying electricity

to the desired destination

• There are not many hydroelectric plants in Kansas or Florida but

there are several in Washington. Why?

http://energyquest.ca.gov/story/chapter12.html

mechanical

electrical

Land is too flat---best to have hydropower where

there is change in elevation (mountainous areas with rivers)

III. Wind Energy

• Wind energy is the second most used renewable energy

source in the U.S.

• It utilizes the following energy conversions:

_____________ _________________ ______________

How it works

• Wind turbines utilize the movement of the wind to create

energy

1. Blowing wind (______) spins the blades on a wind

turbine (___________)

2. The blades are attached to a shaft which spins a

generator to create electricity (________)

Kinetic Energy Mechanical Energy Electrical Energy

mechanical

electrical

kinetic

• Wind turbines are placed on a tower to capture the most energy

(at 100ft or more the wind is faster and less choppy)

• In order for a wind turbine to work efficiently, wind speed must be

above 12-14mph.

• The blades don’t turn the main shaft fast enough to generate

electricity so gears are used to speed up the rotation

• A brake is also built in to prevent the blades from turning too fast

and being damaged

• The Great Plains use wind-powered electric plants the most.

Why?

https://www.youtub

e.com/watch?v=ts

ZITSeQFR0

Consistently windy there

IV. Biomass Energy

• Biomass= ____________ from living or recently living

organisms

o Examples: wood, crops, animal manure, human sewage

• The ________ in biomass comes from the ____

• The main way biomass energy is made use of is through the

following conversions: _________ ________

___________ _________

How it works

1. The organic matter gets burned, undergoing a combustion

reaction that releases heat (_________)

2. The heat from the combustion boils water into steam

(________) which turns turbines (___________)

organic matter

energy sun

chemical

electricalmechanical

thermal

chemical

thermal mechanical

3. The turbines power a generator which generates electricity

(_________)

• Biomass is an alternative to burning fossil fuels

• Burning is only one way to release the energy from biomass

o Can also be converted into useable forms of energy like

methane gas, ethanol, or biodiesel.

electrical

V. Solar Energy

• Solar energy, or __________________, has been used since

the beginning of time and is used daily

• Life would not exist without the energy from the sun

• There are two ways to capture this energy

1. Solar Thermal Electricity

2. Solar Cells or Photovoltaic Energy

1. Solar Thermal Electricity = uses the _________ to

generate electricity

o Utilizes the following energy conversions: ________

____________ ___________

energy from the sun

sun’s heat

mechanical electrical

thermal

How it works

1. Heat from the sun (________) is captured and focused

on a pipe filled with “heat transfer fluid”, typically using

mirrors

2. The fluid transfers its heat to water, causing the water to

eventually boil into steam

3. The steam turns a turbine (___________) which moves

the generator to produce electricity (_________)

mechanicalelectrical

thermal

2. Solar Cells or Photovoltaic Energy = uses the ___________ to

generate electricity

o Utilizes the following energy conversions: ______ _________

How it works

1. Sunlight (_____) strikes solar panels, typically made of the semi-

metal silicon, knocking electrons from the silicon atoms’ loose

2. The ___________ of the free _________ results in the

production of electricity (___________)

• The southwest region of the US utilizes solar power the most. Why?

http://video.natio

nalgeographic.c

om/video/solar-

power

light electrical

sun’s light

Where sun shines the most

light

electricalmovement electrons

VI. Geothermal Energy

• Geothermal energy utilizes _________________

• It undergoes the following energy conversions: _________

___________ _________

How it works

1. Hot water and steam from deep underground get piped up

(________)

2. They travel to a special turbine and turn the blades

(_____________)

3. The turbine’s shaft is attached to a generator which makes

electricity (_________)

heat from the earth

thermal

electricalmechanical

thermal

electrical

mechanical

• Most geothermal plants are located in the western US where

hot water reservoirs are common

o Also common where there is volcanic activity

• Some people use geothermally heated water in swimming

pools or even as their hot water source

• Many geothermal plants “recycle” the hot water or steam

back into the ground to preserve the heat source

VII. Other Energy Sources

• With the increase in technology and decline of fossil fuels,

the search and development of alternative energy sources is

increasing

o Specifically renewable energy

• One of the newer energy sources being explored is the

_______

o Given that the ocean covers 71% of the world’s surface,

much research is being done to try and utilize its energy

• There are 2 basic ways to tap the ocean for its energy:

1. Wave Energy

2. Tidal energy

ocean

• Both ways utilize the same main energy conversions:

_______ ___________ __________

o Same idea as hydroelectric power—energy from the

moving water moves a turbine which powers a generator

mechanical electricalkinetic

• ___________are another alternative electricity source

• Produce electricity by converting ________ __________

o Like a battery

• Most involve combining hydrogen and oxygen = hydrogen

fuel cell

Fuel cells

chemical electrical

Nuclear Energy

Pros Cons

• low greenhouse gas

emissions

• Produces lots of energy

• Reliable energy source

• Low operating costs

(expensive to set up

plant but not to run it)

• Creates radioactive

waste

• Hard to dispose of waste

(_____________)

• Used for terrorism

• Nuclear melt-

downs/accidents

• Uranium is finite material

Fossil Fuel Energy

Pros Cons

• Cheap (for now)

• Reliable (not dependent

on other factors)

• Produce a lot of energy

• Creates a lot of jobs

• Emit greenhouse gases

= _______________

____________

• Limited supply

VIII. Comparing Energy Sources

long half-lives

acid rain, global

warming

Water Energy

Pros Cons

• __________ energy source

(unlimited supply)

• “Green” energy – low pollution

• _____ than nuclear and fossil

fuels

• One of the ___________

renewable energy sources

• Low maintenance cost

• __________ to build dams

(high construction costs)

• Can affect wildlife

• Risk of drought

Wind Energy

Pros Cons

• Renewable

• Clean fuel source

• One of ________________

energy sources

• Can help pre-existing farms

• Creates jobs

• More energy independence

from foreign countries

• Unreliable

• Requires a lot of ______

• _______

• Suitable in certain areas more

than other

Renewable

Safer

more reliable

Expensive

cheapest renewablespace

Noise

Solar Energy

Pros Cons

• Renewable energy source

(unlimited supply)

• Environmentally friendly

• “energy independence” won’t

have to rely on others for

energy

• Reduce electricity costs

• Low maintenance

• Silent

• Inconsistent

• Expensive to make/set up

• Materials used to make

panels are rare in nature

Geothermal Energy

Pros Cons

• Low pollution

• Renewable – __________

• Lots of energy potential

• Smallest “land footprint”

• Not weather dependent -

reliable

• Can cause earthquakes

• High initial costs

• Specific sites are better than

others

lots of supply

Biomass Energy

Pros Cons

• Renewable energy source

• Low pollution

• Widely available

• Helps ___________ by using it

• Not the cleanest renewable energy

source

• Expensive

• Not the most efficient energy source

Ocean Energy

Pros Cons

• No emission of greenhouse gases

• Renewable

• More predictable/reliable than wind

and solar

• Lots of energy potential

• Lots of maintenance (due to

conditions)

• High costs

• Still developing

Fuel Cell Energy

Pros Cons

• Clean

• Can use renewable fuels

• Lots of energy

• High cost

• Still developing

reduce waste