Environmental Science
Name: ______________________________
Energy
Goal: The student will describe the differences between passive solar heating, active solar heating and
photovoltaic energy and describe the current state of wind energy technology.
Vocabulary:
1. Renewable energy
2. Passive solar heating
3. Active solar heating
Chapter 11.4: Renewable Energy Today
• When we think about _______________________ energy (energy coming from sources that are
constantly being formed), many people think about high tech, solar powered _____________, but life on
Earth has always been powered by the sun
• Other _________________________ energy sources include: wind, water and Earth’s inner heat
• Many governments have plans to _____________________ their use of renewable energy sources. Ex:
European Union planned to produce ___________________% of their energy from renewable by 2010;
thus, reducing the ______________________________ impact of nonrenewable sources
• However, _______________energy sources, including renewable, have an affect on the environment
Solar Energy—Power from the Sun
 Energy from the __________; medium sized star that radiates energy from a nuclear _______________
reaction in its core
 Only a small fraction of that ______________ ever reaches the Earth; enough to power the wind, planet
growth and water cycle, therefore almost all energy comes from directly or indirectly from the ________
 We use ____________________solar energy everyday. Ex: sun shining in a room, heats it up
 _____________________________ – are devices that change the sun’s energy into electricity; these are
not efficient enough for large jobs and are very __________________________ to make
Passive Solar Heating
 _____________________________ form of solar energy; heating something directly
 ______________________ solar heating – used in homes made of materials that help ______________
the inside in conjunction with ________________ efficiency windows that maximize the ‘greenhouse
effect;’ in the Northern Hemisphere, ______________________ facing windows receive the most solar
energy (must be well ________________________________ with thick walls and floors, receive solar
heat by day, slowly release ________________________ by night
 Passive _____________________ heated homes: must have overhang to shade the sun in summer
months when sun is high in the sky and allow _______________________ to enter in winter months
when sun is _____________________ in the sky, also must be in an area which receives a reliable
amount of sunlight (may not need any other type of heating if these conditions exist)
 Any home could _______________________ their energy bills by using these passive solar features
Active Solar Heating
 Solar ______________________heating – solar collectors capture the sun’s energy and transfer it to a
mixture which flows through the ________________________________and is pumped through a heat
exchanger which ______________________________ heats water for use in homes or pools
 More than 1 _______________________ homes in the US use active solar energy to heat water
 8% of __________________________ used in the US is used to heat water; therefore, ______________
solar technology could save a lot of energy
Photovoltaic Cells
 Solar cells, called ________________________________ cells, convert the sun’s energy into electricity
 Invented 120 years ago, now used to __________________ everything from calculators to space stations
 They have _____________ moving parts, they run on nonpolluting power from the _______________;
energy is stored in batteries
 Produces only a very ________________________ electrical current so to use on a large scale would
require several 100’s of acres of solar panels and extended periods of ___________________________
 Since 1985, energy _______________________________ has doubled every 4 years; becoming
increasingly efficient and __________________________ expensive
 Great potential for use in _______________________________ countries; currently, in the developing
world, ___________________ cells provide energy for more than 1 million households
Wind Power—Cheap and Abundant
 Energy from the ___________________ warms the Earth’s surface unevenly, causing air masses to flow
in the atmosphere
 _______________________ in the wind can be harnessed by windmills which are attached to electrical
generators; new wind turbines are cost ________________________and can be erected in three months
 Wind generated electricity is relatively ____________________________, efficient and is the fastest
growing _______________________ source in the world (quadrupled between 1995 and 2000)
Wind Farms
 Large arrays of wind _________________________ are called wind farms
 In California, ________________________ wind farms supply electricity to 280,000 homes; small wind
farms (20 or fewer turbines) are becoming common and take up _______________________ space
 ___________________________ wind is not consistent enough in most areas to make it feasible
 Windmills are very ______________________ structures and their blades can interfere with
communications (cell phones)
 Some __________________________ farms are putting in wind farms and then sell the electricity they
generate to the local utility companies.
An Underdeveloped Resource
 The windiest spots on Earth could generate _______________ than ten times the energy used worldwide
 All the large energy companies are developing ways to use more __________________power
 Problem: _______________________ the energy from rural areas where it is generated to urban centers
 Wind energy in the _____________________ may be used to produce ______________________ from
water to be trucked or piped to cities for use as a ___________________.
Lesson Reflection:
- Origami Windmill
Assessment:
1. Describe the differences between passive solar heating, active solar heating and photovoltaic energy.
2. What is the current state of wind energy technology?
Active Reading: Renewable Energy Today
Lesson Extension (Technology/Application/Connection to Real World):
 Visual display of a wind farm
 NOVA video: Saved by the Sun (53 min)