An overview of how electricity is generated by various energy sources.

1. Energy !
How Electrical Energy is made commercially.
By E. B. Allred

2. Commercial Energy Sources
• Coal
• Oil
• Natural Gas
• Nuclear
• Hydro
• Geothermal
• Wind
• Waste Methane
• Solar

3. Coal
Delta Utah
After coal is unloaded from trains, it is pulverized to fine
powder and blown into the furnace where is explodes in
the flame. Water in pipes in the furnace turns into high
pressure steam that is sent to the turbine.

4. Coal fired electrical power plant
Coal fired electric plants require thousands of tons of coal
per day. Coal plants have been fitted with exhaust
“scrubbers” and ash traps but are still a significant source
of atmospheric pollution. Coal is a non-renewable
resource. Coal and Oil are a form of stored solar energy,
from plants and animals that lived long ago.

5. Steam made in the
coal furnace is piped
into the turbine that
spins the generator.
There are about 620
coal fired power
plants in the United
States. (DOE)
America gets 50%
of its electrical
power from coal
fired plants. (NEF)

6. Oil
Boilers burn fuel oil to
make steam which is
routed to a turbine that is
connected to a generator.
Although cleaner than coal,
oil creates air pollution too.
America gets about 2% of its electricity from oil (DOE).
Most oil is used in transportation rather than electricity
generation.
Oil is a non-renewable energy source.
America imports over 50% of the oil it consumes. The
U.S. is the world’s largest oil consumer. (NEF)

7. Natural Gas Electrical Generation
Natural gas has the lowest carbon dioxide emissions of all
fossil fuels.
Natural Gas is a non-renewable resource.
America gets about 22% of its electrical energy from
natural gas. (NEF)

8. 1. Cooling tower 10. Steam control valve 19. Superheater
2. Cooling water pump 11. High pressure steam turbine 20. Forced draught (draft) fan
3. Three-phase transmission line 12. Deaerator 21. Reheater
4. Step-up Transformer 13. Feedwater heater 22. Combustion air intake
5. Electrical generator 14. Coal conveyor 23. Economiser
6. Low pressure steam turbine 15. Coal hopper 24. Air preheater
7. Boiler feedwater pump 16. Coal pulverizer 25. Precipitator
8. Surface condenser 17. Boiler steam drum 26. Induced draught (draft) fan
9. Intermediate pressure steam turbine 18. Bottom ash hopper 27. Flue gas stack
Power plants using coal, natural gas, or fuel oil are
typically about 50% efficient, meaning that at least 50%
of the energy is wasted, unusable for electrical power
generation.
Simplified thermal power station

9. Nuclear Power
Heat from the reactor core is transferred from the
radioactive loop to the non-radioactive water loop through
a heat exchanger where it makes high pressure steam for
a turbine to spin a generator to make electricity. From 65
nuclear power plants, America gets almost 20% of its
electricity from nuclear power plants. (DOE)

10. What about Nuclear waste?
The spent fuel from a nuclear
power plant is dangerously
radioactive, and will remain that
way for about 25,000 years. Where
can it be stored safely?
Except for radioactive waste,
nuclear power makes no pollution.
It is estimated uranium supplies can
last 50 to thousands of years,
depending on technology used.
Nuclear Energy is a non-renewable
energy resource.

11. Hydro

12. How a hydroelectric dam works

14. Generators that make the electricity require a lot of
power to spin them. Water flowing through the
turbines spins the generators.
America gets only about 6% of its electricity from
hydroelectric dams. (National Energy Foundation)

15. Geothermal
A geothermal electric plant
operates just like a coal fired
plant except that the heat
source to make steam comes
from hot water or steam
under ground.
After hot water cools off it is
pumped back underground.
This completes a “closed
loop”, just like in a nuclear
power plant.

16. Steam is piped to turbines that spin an electric
generator. Cooling towers condense used steam back
into water to be reheated again underground.
America gets about 1% of its electricity from
geothermal plants. (DOE)

17. Wind
Wind powered electrical
generators rely upon a
steady wind. Wind
generators are placed
where wind is frequent such
as canyons and slopes of
hills.
America generates only
about 0.5% of its electricity
this way. (NEF)
Wind power is expected to
have a much greater role in
the future.

18. Biomass
Garbage methane wells
Rotting garbage creates lots of
methane gas. Methane gas is
buried under a layer of topsoil
where it is collected in “wells” and
piped to large engines that burn
the methane, and in turn, spin
electric generators.

19. Methane burns cleaner than
other fossil fuels, but it still
produces air pollution.
Biomass is considered a
renewable resource,
supplying less than 1% of
our energy . (NEF)

20. Photovoltaic (PV) electrical
power generation is an
Emerging Technology.
PV cells create electricity
directly from sunlight.
Typically, they are only
about 15% efficient. (NEF)
Photovoltaic cells are only a minor contributor to
U.S. electricity.
Solar

21. Solar
Solar concentrating reflectors (mirrors) are used to
make intense heat from sunlight. This heat makes
steam, used to turn turbines, to generate electricity.

22. Solar Concentrator Electrical power plant
Concentrating solar radiation to make heat is a much
more efficient way to make electricity from sunlight.
America gets about 0.5% of its electricity from solar
power. (NEF) This is an Emerging Technology.

23. year Coal Oil
Natural
Gas Nuclear Hydro
Other
Renewables
1996 52% 2% 13% 20% 10% 2%
1997 53% 3% 14% 18% 10% 2%
1998 52% 4% 15% 19% 9% 2%
1999 51% 3% 15% 20% 9% 2%
2000 52% 3% 16% 20% 7% 2%
2001 51% 3% 17% 21% 6% 2%
2002 50% 2% 18% 20% 7% 2%
2003 51% 3% 17% 20% 7% 2%
2007 49% 2% 22% 19% 6% 3%
2016 30% 0.6% 34% 20% 6.5% 8.4%

26. Misc. Review Facts
1. Coal generates about 23% of the electricity in the USA.
2. Solar, wind, Geothermal, and hydroelectricity generate no pollution.
3. Nuclear power generates radioactive waste that is difficult to dispose
of.
4. Coal, oil, natural gas, and methane systems generate atmospheric
pollution.
5. Nuclear power generates no air pollution.
6. Nuclear, oil, coal, methane, and Geothermal systems operate
independently of the weather.
7. Solar, wind, and hydroelectric systems depend on the weather.
8. Solar, wind, and geothermal systems are emerging technologies.
9. The United States has enough coal to power the world for the next 100
years.
10. Hydroelectric systems depend on large reservoirs or constant flowing
streams and rivers, so they are limited in number because of available
places to build them.

27. More Misc. Review
11. A nuclear reactor’s heat is transferred through a heat exchanger.
12. Typical photovoltaic (PV) cells are presently only about 15%
efficient.
13. A great deal of energy, typically, up to 50% in any (thermal) electric
generating plant is lost to excess heat.
14. A steam or gas turbine is very much like a jet aircraft engine.
15. A hydroelectric turbine is very much like an aircraft or boat
propeller.
16. Photovoltaic cells (PV) convert sunlight directly into electricity.
17. Coal and oil is a form of stored solar energy.
18. Today’s oil production has PEAKED and isdeclining.
19. Geothermal systems are limited in number because of the depth of
most hot layers of rock.
20. Natural gas is the cleanest of the fossil fuels.

29. Commercial Energy Sources Quiz
1. Are there good jobs & careers in the energy production
business?
2. What type of power plants generate the most electrical
energy in the United States?
3. Name two energy producer methods that do not pollute our
environment.
4. Which type of energy production generates the most
pollution?
5. Is solar-electric energy production a major or minor producer
of electricity in the United States?
6. What is the most challenging problem related to nuclear
electric power production?

30. Quiz Continued
7. Name two means of electrical production that do not
depend upon the weather.
8. Name two means of electricity production that are
considered emerging technologies.
9. Which type of electrical generation depends on good
rainfall and/or snow pack?
10.Which is the cleanest of the fossil fuels to burn?
11.Which country is the world’s largest oil consumer?
12.Which is more efficient, photovoltaic cells or concentrating
solar heat for electrical generation?

31. Quiz Continued
13.Define a renewable energy resource.
14.Which energy type of generation smells bad but is
considered a fairly clean (nonpolluting) and renewable
resource?
15.What is the easiest and simplest thing that can be done to
decrease electricity consumption in the United States ?

32. Quiz Answers
1. Yes, there are good jobs and careers in energy production.
2. Coal fired electrical generating plants.
3. Wind and Solar electrical generation plants.
4. Coal fired generators create the most pollution.
5. minor
6. dealing with radioactive waste.
7. Any 2 of: nuclear, coal, oil, natural gas, geothermal
8. Any 2 of: wind, solar, geothermal, oil shale, clean coke,
biofuels or waste methane.
9. Hydropower

33. Quiz answers
10.natural gas
11.United States of America
12.concentrating solar heat
13.Energy sources that can be regenerated.
14.Biomass produces methane gas that stinks but is fairly clean
burning.
15.Any of:
Walk, ride a bike, take the bus, vacation near home,
turn off the lights when not in use, use efficient appliances,,
put on a sweater, turn down the heater and air conditioner
PRACTICE CONSERVATION!