Transcript Chapter 15
Chapter 15: Foundations of a
Sustainable Energy System
Conservation and Renewable Energy
Energy Efficiency Options
There’s no shortage of easy, economical ways to
save energy.
Because energy is used so inefficiently, huge cuts in
energy demand can be made by applying efficiency
measures.
Much of our future energy demand can be met by
freeing up energy currently wasted in three areas:
transportation
buildings
industry/business
Personal use
The Potential of Energy Efficiency
Extremely energy-efficient vehicles are
currently available.
Many improvements in vehicles could
increase efficiency even more, greatly cutting
transportation energy consumption.
The hypercar
The
Chevrolet
Volt
Copyright 2008 GM Corp. Used with permission, GM Media Archive.
Copyright © 2005 Hypercar, Inc. (www.hypercar.com) and Fiberforge
(www.fiberforge.com). Used with permission.
FIGURE 3: Energy consumption in transportation sector
The Potential of Energy Efficiency
Energy-efficiency measures in buildings can result in
substantial energy savings in:
Heating
Cooling
Lighting
Appliances and electronic
equipment
Courtesy of OSRAM SYLVANIA
Promoting Energy Efficiency
There are many ways to use energy much more
efficiently.
There are also many ways to promote this strategy,
including:
Roadblocks to Energy Conservation
Many roadblocks stand in the way of energy
efficiency, including:
the illusion of abundance
federal subsidies that underwrite fossil fuels’ true costs
higher initial costs for some energy-efficient products
powerful political forces
Despite this, energy efficiency is becoming a popular
strategy.
15.2 Renewable Energy Sources
Renewable energy will very likely become a
major source of energy in the future.
The transition to a renewable energy future
has already begun in some nations.
FIGURE CO:
Offshore wind turbines
© Ali Azhar/ShutterStock, Inc.
Solar Energy Options
Solar energy is considered a renewable energy
source, but it is really finite.
Nonetheless, because it is so abundant and clean, it
will very likely be a major contributor to future world
energy supplies.
Buildings can be designed to capture solar energy to
provide space heat.
Properly designed structures can derive 100% of
their heat from the sun.
FIGURE 5: Map of global solar energy availability
FIGURE 6: A passive solar house
FIGURE 07: A solar
retrofit: Sunlight
penetrates the
greenhouse glass
and is stored in the
floor or in waterfilled drums
Solar Energy Options
Active solar systems generally employ rooftop
panels that collect heat from sunlight and
store it in water or some other medium.
FIGURE 08a: An
active solar heating
system
© Mediacolor’s/Alamy Images
Solar Energy Options
This solar energy can then be used to heat
domestic hot water or to heat the interior of
the building.
FIGURE 08b: Schematic of
photovoltaic panels
Solar Energy Options
Photovoltaics are thin wafers of material such as
silicon that emits electrons when struck by sunlight,
creating electricity.
Although photovoltaics are costly, prices are falling.
Solar thermal electric facilities
heat water using sunlight.
Steam from this fairly
cost-competitive process
is used to generate electricity.
FIGURE 10b: A solar thermal electric system
© Jim Noelker Stringer/AP Photos
FIGURE 10a: An active solar heating system: Flat plate collectors
circulate a fluid through pipes in the collector to a storage tank
Solar Energy Options
Solar energy technologies are well developed.
Their advantage over other forms
of energy production is that
they rely on a free, abundant
fuel and are relatively clean
systems to operate.
Although some systems are
economically competitive,
others are still fairly costly.
Storing energy from intermittent
sunlight remains one of their
major drawbacks.
Courtesy of Kyocera Corporation
FIGURE S04_1: The Kyocera
Office Building
Wind Energy
Winds are produced by solar energy and can be
used to generate electricity or to perform work
directly, such as pumping water.
Wind energy is clean,
abundant, and fairly
inexpensive, especially
when one includes its
low environmental
costs.
FIGURE 12a: A windmill
generator farm in Wyoming
Courtesy of Matt Reuer, Colorado College
Wind Energy
Wind energy could provide a significant
percentage of our future energy demand.
However, because winds are often
intermittent, backup systems and storage are
necessary.
FIGURE 12b: Wind farm near
Canestota, New York
Courtesy of Dan Chiras
FIGURE 13a: World wind energy generating capacity
Data from The World Wind Energy Assocation, Press Release February
21, 2008, Wind Turbines Generate More than 1% of the Global Electricity
(Bonn; World Wind Energy Assocation 2008).
Biomass
Biomass is organic matter such as wood or
crop wastes that can be burned or converted
into gaseous or liquid fuels.
It is a common fuel source in most developing
nations but supplies only a fraction of the
needs of people in the developed nations.
Biodiesel
Biodiesel is a renewable fuel made from an
assortment of vegetable oils and a methanollye mixture
There are many potential sources for
biodiesel
Hydroelectric Power
Hydroelectric power is renewable and operates
relatively cleanly, but dams and reservoirs have
an enormous impact on the environment.
Although potential hydropower sources are
enormous, they can be far from settlements,
and developing them would cause serious
environmental damage.
FIGURE 14: Smallscale hydropower
Geothermal Energy
Geothermal energy is a renewable resource
created primarily from magma, molten rock
beneath the crust.
Geothermal energy is used to generate
electricity and to heat structures.
Geothermal Energy
It is a major source of energy in some countries.
FIGURE 15: Global geothermal resources
Hydrogen Fuel
Hydrogen may
become an important
fuel in the future.
Hydrogen can be
produced by passing
electricity through
water, a renewable
resource.
When hydrogen
burns, it produces
water vapor.
Courtesy of Ballard Power Systems (www.ballard.com)
Hydrogen Fuel
Fuel cells use hydrogen, either from water or
organic fuels, to produce electricity.
The electricity can be used to power cars,
and several manufacturers are actively
pursuing this option.
FIGURE 16b: A fuel cell
Courtesy of Ballard Power Systems (www.ballard.com)
15.3 Is a Renewable Energy
Supply System Possible?
Renewable energy is abundant and accessible
without major technological breakthroughs.
It has many applications with sufficient potential
to replace nuclear and fossil fuel supplies.
The Sustainable Energy Strategy
Shifting to a
sustainable system
of energy will take
many years.
FIGURE 17: Transition to a
sustainable energy supply
system
Economic and Employment Potential of
the Sustainable Energy Strategy
Several renewable
energy technologies
provide competitively
priced electricity while
creating more jobs
than do fossil fuels
and nuclear energy.
FIGURE 18: Employment
opportunities provided by different
types of energy