Environmental Science
Name: ______________________________
Energy
Goal: The student will describe three alternative energy technologies, identify two ways that hydrogen could
be used as a fuel source in the future and explain the difference between energy efficiency and energy
conservation,
Vocabulary:
1. Energy conservation
Chapter 11.6: Alternative Energy and Conservation
 Our goal is to achieve a future where energy use is ______________________________, to do this we
must: 1) make the __________________ of the energy resources we already have, and 2) develop new
sources of _________________________
 ________________________________ energy describes energy sources that are still in development,
ex: geothermal power was once considered an alternative energy
 In order for it to be considered ____________________, it must prove to be __________ effective and
the ____________________________________ effects of using the energy source must be acceptable
 The government must __________________in the energy source in order to do the research needed
Tidal Power
 _______________ are the movement of water in the oceans and seas caused by gravitational attraction
between the sun, Earth and the moon; happen ____________________ each day; marked by rising and
falling of ______________ level
 Tide power was used in Britain and France a _________________ years ago to power their mills; today,
it is used to __________________________ electricity in countries such as France, Russia and Canada
 Tidal power plants work like a hydroelectric dam; when tide __________________, water flows behind
a dam; when tide ________________________ water trapped behind the dam releases, turns a turbine
which generates electricity
 Will not become a ____________________________ source of energy in the future because the cost of
building and maintaining a facility is _______________ and there are only a few suitable locations
Ocean Thermal Energy Conversion
 Differences in temperatures between ________________________ water and deep ______________
water in the _________________________ can be as much as 24 degrees C (43 degrees F)
 Off the shores of ______________________________ there is an experimental power station, uses this
temperature difference to generate electricity
 OTEC -- ________________________ surface water is used to boil sea water (water boils at low
temperatures when it is at low pressure in a vacuum chamber), boiling water turns to ______________,
which spins a turbine, which runs an ___________________________ generator, cold water from the
deep ocean ____________________ the steam, turning the steam into water which can be used again
 Problem: ____________________ of the energy generated at the plant is used to pump cold water up
from deep in the ocean; not cost effective and _________________________________
 The environmental effects of pumping ____________ amounts of cold water to the surface are unknown
Hydrogen—A Future Fuel Source?
 Most ________________ substance on Earth and can be burned as a fuel; could be the fuel of the future
 Water is 2 parts hydrogen, one part oxygen; when _______________ from oxygen, hydrogen is a cleanburning gas that has great promise as a fuel for the future; it is a ____________________________ fuel
because it does not contain carbon

Most internal-combustion engines ____________ run on hydrogen gas without any major modifications
The Challenge of Hydrogen Fuel
 Why is hydrogen the fuel of the ____________________________ and not the fuel of today?
 Drawbacks: takes a lot of _________________________ to produce it; separating it from oxygen
requires energy; it is not concentrated enough and would require __________________ amounts at any
one time so it would need to be either __________________________________ to a very high pressure
or chilled to extremely ________________ temps
 Could possibly be ______________________ in pressurized tanks and transported in ______________
pipelines or not be stored at all, it might be used as it is produced in fuel cells
Fuel Cells
 Could possibly be the __________________________ of the future; like a battery, fuel cells produce
electricity chemically (combining hydrogen with oxygen); produces electricity and water as a byproduct.
 _____________________________ can be fueled by anything (hydrogen, natural gas, alcohol, gasoline)
 Fuel cells have been used by ________________________shuttles for years
 By 2010, they felt many _______________________ devices (phones, video games) would be powered
by fuel cells; fueled with alcohol which would end the problem of charging or changing batteries
Energy Efficiency
 __________________ main ways to reduce energy use: lifestyle changes (walking, biking, using mass
transit) and ______________________________ in energy efficiency (percentage of energy put into a
system that does useful work)
 Can be determined by using this simple equation:
energy efficiency (in %) = energy in/energy out x 100
 Most of our devices are inefficient; more than 40% of all __________________________ energy used
in the US is wasted; mostly from inefficient ___________________wasting vehicles, furnaces,
appliances and leaky, poorly insulated buildings
 We could save _______________________________ amounts of energy by using fuel cells instead of
internal combustion engines in cars and by changing from using incandescent to fluorescent light bulbs
Lesson Reflection:
 .
Assessment:
1. Describe three alternative energy technologies and identify two ways that hydrogen could be used as a
fuel source in the future.
Lesson Extension (Technology/Application/Connection to Real World):
 NOVA video: Power Surge (53 min)