Chapter 15: Foundations of a Sustainable Energy System

Conservation and Renewable Energy

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

Energy Efficiency Options

Extremely energy-efficient vehicles are currently available.

Many improvements in vehicles could increase efficiency even more, greatly cutting transportation energy consumption.

The Potential of Energy Efficiency

Copyright © 2005 Hypercar, Inc. (www.hypercar.com) and Fiberforge (www.fiberforge.com). Used with permission.

Copyright 2008 GM Corp. Used with permission, GM Media Archive.

The hypercar The Chevrolet

Volt

FIGURE 3: Energy consumption in transportation sector

Energy-efficiency measures in buildings can result in substantial energy savings in:

Heating Cooling Lighting Appliances and electronic

equipment

The Potential of Energy Efficiency

Courtesy of OSRAM SYLVANIA

There are many ways to use energy much more efficiently.

There are also many ways to promote this strategy, including:

Promoting Energy Efficiency

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.

Roadblocks to Energy Conservation

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 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.

Solar Energy Options

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 water-filled drums

Active solar systems generally employ rooftop panels that collect heat from sunlight and store it in water or some other medium.

Solar Energy Options

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

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 facilitiesheat water using sunlight.

Steam from this fairlycost-competitive processis used to generate electricity.

Solar Energy Options

© Jim Noelker Stringer/AP Photos

FIGURE 10b: A solar thermal electric system

FIGURE 10a: An active solar heating system: Flat plate collectors circulate a fluid through pipes in the collector to a storage tank

Solar energy technologies are well developed.

Their advantage over other formsof energy production is thatthey rely on a free, abundantfuel and are relatively cleansystems to operate.

Although some systems areeconomically competitive,others are still fairly costly.

Storing energy from intermittentsunlight remains one of theirmajor drawbacks.

Solar Energy Options

Courtesy of Kyocera Corporation

FIGURE S04_1: The Kyocera Office Building

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 fairlyinexpensive, especiallywhen one includes itslow environmentalcosts.

Wind Energy

Courtesy of Matt Reuer, Colorado College

FIGURE 12a: A windmill generator farm in Wyoming

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 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.

Biomass

Biodiesel is a renewable fuel made from an assortment of vegetable oils and a methanol-lye mixture

There are many potential sources for biodiesel

Biodiesel

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.

Hydroelectric Power

FIGURE 14: Small-scale hydropower

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

Geothermal Energy

It is a major source of energy in some countries.

FIGURE 15: Global geothermal resources

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.

Hydrogen Fuel

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)

Renewable energy is abundant and accessible without major technological breakthroughs.

It has many applications with sufficient potential to replace nuclear and fossil fuel supplies.

15.3 Is a Renewable Energy Supply System Possible?

Shifting to a sustainable system of energy will take many years.

The Sustainable Energy Strategy

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