Link: https://www.annapolishighschool.org/apps/video/watch.jsp?v=34649
Study Guide: Study Guide to Modern Marvels - Renewable Energy (25 points)
Exit Quiz: Exit Quiz for the Documentary Modern Marvels - Renewable Energy
Study Guide to Modern Marvels: Renewable Energy
1. What size area would need to be covered with photovoltaic panels to generate enough
electricity for the entire US? What is perhaps the earliest use of solar thermal
technology? 2 pts
A square area roughly 100 miles × 100 miles (about 10,000 square miles) covered in
photovoltaic panels could theoretically generate enough electricity for the entire United States.
One of the earliest uses of solar thermal technology was by the Anasazi, ancient Greeks and
Romans, who designed buildings to capture the sun's heat — but in a more modern sense,
solar thermal collectors were used in the late 1800s to heat water and run small engines.
2. What is the difference between solar voltaic and solar thermal energy? 1 pt
Photovoltaic (PV) cells convert sunlight directly into electricity using semiconductors. Solar
thermal technology uses sunlight to generate heat, which can warm water, heat buildings, or
produce steam to drive turbines for electricity generation.
3. What are some of the very important modern uses of photovoltaic cells? 1pt
PV cells power satellites and spacecraft, off-grid homes, water pumps, gps, global
communication, and large utility-scale solar farms feeding the electrical grid.
4. How has the price of photovoltaic electricity been brought down to make it competitive
with other types of electrical generation? 2 pts
Mass production and manufacturing efficiencies have dramatically reduced the cost of solar
panels. Improvements in cell efficiency (getting more electricity from the same panel area) and
economies of scale — producing millions of panels in large factories — have made
solar-generated electricity increasingly competitive with coal and gas.
5. What parts of the US have good, efficient levels of winds to make wind power
worthwhile? What technical advances in wind turbine technology have made wind power
competitive with gas and coal? 2 pts
The Great Plains (from Texas through the Dakotas) and coastal and offshore areas have the
strongest and most consistent winds. Technical advances include much taller towers (reaching
stronger winds higher up), longer and lighter blades, and sophisticated computer controls that
adjust blade pitch automatically to maximize efficiency in variable winds.
6. Which nation has invested the most in wind energy innovations and has some of the
largest turbines? What two nations have the largest total potential for generating wind
energy? Which of these two nations is making the largest investment? 2 pts
Denmark has invested the most in wind energy innovation and operates some of the largest
turbines. The two nations with the largest total wind energy potential are the United States and
China. Of those two, China was making the largest investment.
7. What nation gets over half of its energy needs from geothermal sources? What are
some of the ways this nation uses this geothermal energy? What percent of homes in
this nation use water naturally heated by geothermal sources? 2 pts
Iceland gets over half of its energy needs from geothermal sources. The country uses
geothermal energy for heating homes and buildings, heating greenhouses for year-round
agriculture, heating outdoor swimming pools, and generating electricity. About 90% of homes in
Iceland use water naturally heated by geothermal sources.
8. What is ground-sourced geothermal energy and how does it work to heat and cool
buildings? 2pts
Ground-source (or ground-coupled) geothermal uses the fact that just a few feet below the
surface, the earth maintains a stable temperature year-round. A system of pipes is buried in the
ground and filled with fluid. In winter, the fluid absorbs heat from the ground and transfers it into
the building. In summer, the process reverses — the system pulls heat out of the building and
deposits it into the cooler ground, acting as air conditioning.
9. When and where was the first large-scale geothermal plant built and how many homes
does this power plant still service? 1pt
The first large-scale geothermal power plant was built at The Geysers in California in 1960. It
still generates enough electricity to power roughly 725,000 homes.
10. What types of fuel were diesel motors and Fords Model-T motors originally designed
to run on? 1 pt
Rudolf Diesel originally designed his diesel engine to run on peanut oil (vegetable oil). Henry
Ford designed the Model T to run on ethanol (grain alcohol/hemp fuel), envisioning American
farmers as the fuel suppliers.
11. What is the difference in efficiency between fossil fuel used to produce corn ethanol
and ethanol from sugar cane? What nation most takes advantage of this significant
difference in efficiency? What biofuel source is even more efficient than sugar cane? ​
3 pts
Producing ethanol from corn yields only about 1.3 units of energy for every 1 unit of fossil fuel
invested — a very slim margin. Sugar cane ethanol yields roughly 8 units of energy for every 1
unit of fossil fuel invested, making it dramatically more efficient. Cellulosic ethanol — made from
switchgrass, agricultural waste, or woody biomass — is potentially even more efficient than
sugar cane and doesn't compete with food crops.
12. What simple idea was developed by the California Cars Initiative to overcome the
limitations of both hybrid (gas and electric) cars and completely electric cars? What are
the advantages of these cars? 2 pts
The California Cars Initiative developed the idea of a plug-in hybrid — a car that combines a gas
engine with a battery pack large enough to handle most daily driving on electricity alone, while
the gas engine serves as a backup for longer trips. The advantages are: you can charge at
home overnight using cheap off-peak electricity, dramatically cut fuel costs, reduce emissions
for daily commutes, and never have the "range anxiety" of a fully electric car.
13. How do tidal barrages generate electricity and when and where was the first tidal
barrage developed? What advantages do below ocean turbines have over wind turbines?
2 pts
A tidal barrage works like a dam built across a tidal estuary. As tides flow in and out, water
passes through turbines in the barrage, generating electricity. The first large tidal barrage was
built on the Rance River estuary in Brittany, France, opening in 1966. Underwater (tidal stream)
turbines have an advantage over wind turbines because water is about 800 times denser than
air, meaning the turbines can be much smaller while generating equivalent power, and the tides
are completely predictable, unlike wind.
14. How does the Scottish-built wave generator work and where is it now generating
power? 1 pt
The Pelamis Wave Energy Converter, built in Scotland, consists of a series of connected
cylindrical sections that flex with the motion of ocean waves. This flexing drives hydraulic pumps
that generate electricity. It was deployed off the coast of Portugal (near Póvoa de Varzim),
where it became one of the world's first commercial wave energy installations.
15. What is meant by ‘flipping’ our sources of energy? 1 pts
"Flipping" refers to inverting our current energy model — instead of getting ~80% from fossil
fuels and ~20% from renewables, we would flip it so that ~80% comes from renewable sources
(solar, wind, geothermal, biofuels, tidal, wave) and only a small fraction from fossil fuels. It's not
about a single new technology, but about scaling up and combining all the renewable
technologies we already have.