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Ms. Farrell

on 28 March 2015

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Transcript of Energy

Useable Forms of Energy
Renewable vs Nonrenewable
Natural Gas
Useable Energy in the United States
Natural Gas: 24%
Renewable Energy: 7%
Oil: 37%
Nuclear Fuels: 9%
Coal: 23%
Crude oil/liquid petroleum
gasoline, diesel fuel, jet fuel, heating oil
How it's formed:
Forms from heating and compression of ancient organic matter
Generally formed by phytoplankton (algae) in oceans
covered by a nonporous rock
Oil Refining:
Crude Oil is the raw material removed from the ground
The refinery process is dangerous and expensive
Requires heating the oil to separate it into its different parts
From heaviest to lightest:
Jet fuel
How we use Crude Oil
US uses more crude oil than any other fuel
3.1 billion liters/day
Mainly used for transportation
Gasoline accounts for 1/2 of crude oil used
other uses include:
pharmaceuticals (raw material)
cleaning solvents
Advantages and Disadvantages of Petroleum
Oil Spills
Arctic National Wildlife Refugee
Convenient to transport and use
Cleaner burning than coal (15% less CO2 emissions)
Oil contains:
All released into the atmosphere when burned
Always chances for oil spills when drilling
oil leaks naturally during drilling
can contaminate drinking water
1989 Exxon Valdez
53 million gallons
2010 Deepwater Horizon spills
206 million gallons
1991, Persian Gulf War
240 million gallons
Scientists continue to debate about the consequences
pipeline could melt permafrost and interfere with calving grounds of caribou
19 million acres of protected land

potential 378 billion gallons of oil
How it's formed
Remains of plant material that were preserved
280 million to 360 million years old
Types of Coal
Four types that form as time & pressure increase
Precursor- Peat
How Coal is Extracted
Mining Detor....
Surface Mining
technological demands are small
Economic Costs are Low

Subsurface Mining
Technological demands increase
human health consequences increase
Surface Mining
3 different types
Effects on Air
Effects on Water
Effects on Soil
Effects on Biodiversity
Effects on Humans
Strip Mining
Open-Pit Mining
Mountaintop Removal
Removal of "strips" of soil and rock to expose ore such as coal
land waste, or tailings, are filled into pits
a variety of strategies can be used to restore the affected area
Land can usually be restored back to its original state
Creation of a large pit or hole in the ground that is visible from Earth's surface
Ore extends both horizontally and vertically
*more often associated with copper extraction
Miners remove entire mountaintop with explosives
deposit the "tailings" or unwanted waste material in lower elevations
often into rivers and streams
Significant dust from earth moving equipment
Contamination of water that percolates through the "tailings" or waste material
the tailings can contain acids and metals
Most soil removed from site
May be replaced if reclamation occurs
Habitat alteration and destruction over the surface areas that are mined
Minimal in the mining process
air quality and water quality can be adversely affected near mining operation
Subsurface Mining
Effects on Air
Effects on Water
Effects on Soil
Effects on biodiversity
Effects on People
used when resource is 100 m below earth's surface
begins with a horizontal tunnel dug into the side of a mountain or other feature containing the resource
vertical shafts drilled
elevators bring miners down
Minimal dust at the site
Emissions from fossil fuels used to power mining equipment significant
Acid mine drainage
Contamination of water that percolates through tailings
No significant effects on soil
Road construction to mines fragments habitat
Occupational hazards
from 1900-2006; 11,000 coal miners died
large number die from respiratory disease
Human Health
Advantages/Disadvantages of Coal
Relatively Inexpensive
will last over 200 years
No refining
easy & safe to transport
Economic backbone of some towns
Sulfur, mercury, lead, arsenic
The sulfur is major cause of acid rain
Highest emitter of CO2
After coal is burned, ash is left over
3 to 20 % remain as ash
potential for disaster
Mining practices risk human health
Natural Gas
Composed mostly of Methane:
electricity generation
industrial processes
Transported through pipelines
not accessible in all parts of US
unlikely to be used in cars
1/2 homes use natural gas for heat
Also: Liquid Natural Gas (LNG)
slightly less energy dense
easier transportation
Gas trapped in shale, a type of rock
Water, sand, & chemicals blasted into rock
chemical composition is kept secret (yes, this is legal....)
Only 50-70% of water is recovered
Pros and Cons
Water water water!
Abundant supply
enough energy for over 90 years
Clean burning
40% less CO2 than coal
almost no SO2 (causes acid rain)
Uses an enormous amount of water
7-15 million liters per well
30% unrecoverable
Could contaminate ground water?
CH4 is 25% more effective at trapping sun's energy than CO2
If there is a leak, more catastrophic than CO2
Nuclear Fuels
Not a fossil fuel
Zero carbon emissions
Gets a bad reputation
Nuclear accidents
Chernobyl (1986)
Estimated death total 4,000
Japan earthquake (2011)
0-100 cancer deaths
Nuclear fuels as a potential weapon
How it works
Energy harvested from Nuclear Fission
a form of nuclear decay
A large, radioactive particle is hit with neutrons.
The atom is split
Energy released
Radioactive Waste
Possibility of Accidents
The Debate Continues
No air pollution emitted
only a little CO2 during uranium mining
Ample supply of Uranium
Offers independence from imported oil
After it has been used as an energy source, waste fluid is still radioactive
high-level waste: used fuel rods
low-level waste: contaminated protective gear
uranium mine tailings
high-level worst for the environment
half-life: time it takes for 1/2 radioactive material to decay
Uranium-235; half life of 704 million years
Half-life math
The average American continuously uses 10,000 watts of energy
How much energy do we use in a day?
Let's quickly review energy vs power. Remember, watts is a rate of energy use, kwh is how we measure an amount of energy
We use 240 kWh per day
that's roughly 19 gallons of petroleum per day!
So, where does all this energy come from?
All derived from fossil fuels
We burn the fuel and harvest the heat energy from combustion
Two major categories of energy
1. fossil fuels
2. Nuclear
energy gained from radio active material
Energy is not shared evenly
US energy use is 5x the world average
40% of all energy is converted to electricity
electricity can be made from nearly all forms of energy
the basic principles of creating electricity remain the same.

We get our energy from fossil fuels, nuclear energy, and renewable energy, but we often use it as electricity
Step 1
An energy source needs to be burned and/or converted to heat energy
Step 2
The burning fuel creates heat energy that is transferred to water
Steam is generated
Step 3
The steam moves down a pipe and pushes the blades of a turbine
This movement is what generates electricity
Magnets are moved in opposite directions, exciting electrons
Step 4
Electricity is transferred through interconnected wires collectively called the electrical grid or "the grid"
Step 5
The electricity finally makes it into your home
Formation of Electricity
Here is a more detailed overview
We must remember, as energy is converted, some energy is lost

In this process, 65% of the energy input is lost as heat
Top Producers of Oil:
Saudi Arabia
exempt from clean water act
EPA will not investigate consequences of fracking on water
Calculating Half-Lives

Strontium-90 is a radioactive waste product from nuclear reactors. It has a half-life of 29 years. How many years will it take for a quantity of strontium-90 to decay to 1/16 of its original mass?

It will take 29 years to decay to 1/2 its original mass
another 29 years to 1/4
another 29 years to 1/8
another 29 years to 1/16:

29 + 29 + 29 + 29 = 116 years

Your Turn: You have 180 g of a radioactive substance. It has a half-life of 265 years. After 1,325 years, what mass remains?
Renewable Energy
Nondepletable energy
Biomass (3.6% national energy use)
Our most used renewable energy
Uses sun's energy trapped in plants
4 Common Types:
Wood (often charcoal) and Plants
Animal Products and manure
Landfill gas
liquid fuels (ethanol and biodiesel)

Biomass still releases carbon dioxide! Should we use it?
Carbon released from fossil fuels was removed from the carbon cycle
Increased the total carbon in the cycle
Carbon released from biomass is a part of the carbon cycle presently
The net change of atmospheric carbon should be zero
Theoretically speaking....
It is important to note....
Biomass is POTENTIALLY renewable
cannot remove faster than we replenish
replanting trees is a must
prevent deforestation

Ethanol and Biodiesel (combined 0.6% of total energy)
An alcohol made from corn
Generally mixed with gasoline
90% gas, 10% ethanol
Uses a lot of energy to grow corn and process into ethanol
Less energy dense than regular gas
reduces mileage/gallon by 2-3 mi
Depletes crops grown for food
increase food prices, decrease supply
Extracted oil from plants and algae
Soybean and Palm
Diesel engines need to be modified to run on biodiesel
Any diesel car can be modified
Drive your car for Free!
use vegetable oil from restaurants
Less CO2 emissions than ethanol
not enough to supply the US
Wind Energy (<1%)
Rapidly growing renewable energy resource
Denmark gets 21% of its energy from wind
US produces more energy from wind than any other country
accounts for less than 1% of total US energy use

A wind turbine is able to convert kinetic wind energy into electric energy
Depending on the location and size, a single wind turbine has the potential to provide enough electricity to power 400 homes
Offshore Wind Energy
Offshore wind
a greater source for wind
takes up less space on land
Nantucket Sound Wind Farm
A great deal of resistance within the community
NIMBY attitude (not in my back yard)

Pros and Cons of Wind energy:
Nondepletable, clean
Can share land with other uses
farms, grazing, industry ext.
When wind isn't blowing, no energy produced
batteries can store some energy
expensive and hard to dispose
Can kill birds and bats
estimates of 400,000 birds have been killed from wind turbines in US each year.
People think they are ugly...
Solar Energy
Passive vs Active solar
Passive solar
indirectly using sun's energy
positioning sun to be strong in the winter and deflected in the summer
Using a solar oven
Active solar
Captures the energy of the sunlight with the use of technologies
3 different kinds:
solar water heaters
Photovoltaic solar cells
large scale concentrating solar thermal systems
Solar water heater
Sun's heat is transferred directly to water
Photovoltaic Cells
Sun's energy is captured as light rather than heat
semiconductors exposed to sun convert light to heat
energy can be used directly or stored in a battery
owners can sell their extra energy back to "the grid"
Concentrating solar thermal electricity generation
Mirrors focus sun's energy into one concentrated ray
this ray is used to heat water into steam
the turbine turns a generator producing electricity
This method works best with plenty of direct sunlight and open spaces
use a great deal of land
No electricity generation at night
Second most common form of renewable energy in the US
Moving water is used to turn a turbine to generate electricity

Three Major Forms
Water impoundment system
Water is held behind a small dam
runs through a channel before returning to the river
causes little flooding
produces little energy
Water is stored in a large dam
Gates open and close to control the flow rate of the water
The largest in the United States
The Grand Coulee Dam in Washington state
creates 6,800 MW at max capacity
The largest in the world is in China
Three Gorges Dam on the Yangtze river
provides China with 11% of its yearly energy use
Tidal power
Captures natural movement of water
lakes, streams, estuaries, and bays
Does not have the potential to be a major energy source
produces too little energy
transmission lines can disturb the natural ecosystems
The pros and cons
Use very little fossil fuel
Provide lots of energy
electricity cost less to the consumer
no air pollution, waste product, or CO2 emissions
provides flood control
economic advantage from tourism
Held back water takes up enormous space
generally fertile land for farming
relocates people
Gorges dam relocated 1.3 million people
Can harm living organisms in the water
standing water contains less O2 than flowing water
unsuitable for many species of fish
Heat that comes from natural radioactivity in Earth's crust
Can be used to indirectly to generate electricity
Water is heated in the earth's crust and converted to steam
steam turns a generator
The hot water can also be used directly
for hot water in the home
To heat the home

Achieving Energy Sustainability
Reducing Energy Use
Energy Conservation: finding a way to use less energy
Can reduce the amount of energy used
Can increase efficiency of our appliances

Increase Energy Efficiency
Energy Conservation: finding a way to do the same work using less energy
Ride a bike
lower thermostat
turn of appliances when they are not being used
Can provide incentives for individuals to use less energy
increase public transportation
Tiered Rate Electric system: electric rate is low at first
price increases as use increases
compact fluorescent light bulb
uses 1/4 the amount of energy as traditional incandescent light bulb
Energy-Star Appliances
Thinking clearly about energy efficiency and energy conservation can save you a lot of money in some surprising ways. If you are saving money, you are also saving energy and reducing the emission of pollutants.

Consider the purchase of an air conditioner. Suppose you have a choice:
an Energy Star unit for $300 or a standard unit for $200.

The two units have the same cooling capacity.
The Energy Star unit costs 5 cents per hour less to run.
If you buy the Energy Star unit and run it 12 hours per day for 6 months of the year, how long does it take to recover the $100 extra cost?
Do The Math
Final Thoughts...
No energy resource we are currently aware of can meet all our energy needs in a renewable, non polluting manner
Our best strategy is to reduce energy use and increase energy efficiency
Increase development in renewable energy
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