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