Walkways and Driveways

Rainfall that seeps into the earth receives cleaning as it percolates past soil particles that remove chemicals and microbes. The water then trickles downward into natural aquifers that serve as underground reservoirs for clean drinking water. When communities pave over the ground for roads, driveways, and parking lots, rainwater can do nothing but rush downhill into streams and then to wastewater treatment plants. This event has two drawbacks: Rainwater does not become available for plants and aquifers, and the extra volume of water requires extra energy consumption by wastewater treatment plants. Stress put on treatment plants can be significant in heavy storms, and the incidence of drinking water contamination increases when storms overtax local wastewater treatment facilities. For these environmental and health reasons, permeable pavements offer a useful way to manage and conserve water.

Porous surfaces act as one of the best ways to reuse rainwater and irrigation water. They also reduce runoff to streams. (A) An ecological garden uses stones to create a pathway that allows water to enter the soil. The gardener has planted thyme between these stones. (Kurt Lawton) (B) A pebble driveway helps in water recycling much more than a paved driveway. (Bushnell House)

A permeable pavement is any material that provides pedestrians or vehicles with a strong surface but also allows water to drain through rather than run off the surface. Landscapers select from five main types of permeable pavements, described in the following table.

Permeable pavements must be selected with the soil conditions in mind. For example, clay soils do not drain well and have a tendency to turn to mud in heavy rains. Areas with a very high water table, meaning the area’s natural groundwater storage is close to the surface, present the opposite problem: Permeable materials allow too much water to enter already soaked conditions. Even the best-designed permeable pavements can clog and may need extra maintenance to keep them open.

Microclimates

A microclimate refers to a specific small area that has a climate different from the larger area around it. Eco-landscapers who work in regions that have many diverse microclimates must understand these differences in

Xeriscaping incorporates the best techniques for reducing water waste; xeriscapes often occur in very hot, dry climates. Irrigation covers any area that needs extra water, but it does not waste water on drought-resistant plants. Porous materials for driveways, walkways, and patios allow rainwater to run into the ground, as does the replacement of lawn with gravel.

order to select the best plants for a particular parcel of land. Some microclimates spread over several acres, but other microclimates are so distinct, they cover no more than a half-acre.

 The U.S. Department of Agriculture (USDA) publishes a “Plant Hardiness Zone Map” that shows North America divided into 21 distinct climate zones and helps landscapers and gardeners understand their unique growing conditions. Each different zone on the map contains conditions suitable for certain plants, and landscapers are wise to select plants that do best in these zones. But even within such discrete climate zones, much smaller microclimates often exist. The San Francisco Bay Area in California is a champion of sorts in microclimates: It contains 20 major microclimates and perhaps hundreds of small microclimates across its nine counties. In less than an hour, a person can drive from a hot, dry 100°F (38°C) climate to foggy and windy 50°F (10°C) conditions. During that journey, the driver will likely pass through rain, sunshine, and varying degrees of heat and cold. The San Francisco Chronicle writer Harold Gilliam explained in 2001, “The reasons for this extraordinary variety of weather lie deep in the geologic past—in the clash of tectonic plates. The Pacific plate of the Earth’s crust, moving eastward over the eons, smashed into the edge of the North American continental plate, prying it up into monumental chains of mountains, including the Sierra Nevada, and, much later, California’s coast ranges. It is this rumpled landscape, this hill-and-valley topography, this heterogeneous diversity of landforms that give the Bay Area its multiple climates, microclimates, and submicroclimates.” Each eco-landscape therefore consists of a design best suited to its microclimate.

Environmental engineers must understand geography and climate when seeking energy efficiency because these things contribute to microclimates, which in turn influence the efficiency of buildings and landscaping. The following list summarizes the factors that engineers consider when working with a microclimate:

1. path and intensity of sunlight
2. wind and rain directions
3. wind forces
4. barometric pressure patterns
5. morning, midday, and evening temperature and humidity
6. coldest and warmest temperatures by season
7. cold air drainage
8. soil evaporation rates and tree transpiration rates
9. bodies of water that absorb daily heat and moderate temperatures
10. north- or south-facing slopes
11. soil composition, chemistry, and moisture

 Microclimates and all the many factors they encompass explain why environmental engineers require training in diverse sciences in order to work within the natural boundaries of nature.

Rainwater Harvesting

Rainwater harvesting consists of the collection of rain in rooftop or ground vessels so that the water can be used in irrigation when needed or shunted to a safe water source for indoor use. Collected rainwater, along with gray water and reclaimed water, represents an alternative water source that helps reduce overall household water bills by 25 percent. Gray water is the excess water that runs into household drains connected to sinks, showers, bathtubs, and washing machine rinse cycles. (Blackwater comes from the same sources, plus toilets, and represents any wastewater expected to contain disease-causing microbes.) Water conservation systems pump gray water to holding tanks for later use in irrigation. Reclaimed water is water that has been treated for uses other than drinking, such as treated wastewater from dishwashers.

Rainwater collection systems use gravity to do the work, making these systems easy to use and inexpensive. Rainwater collects into large cisterns, barrels, or rooftop tanks connected to a downspout that carries it to a holding tank on or under the ground. The few precautions that should be taken in managing rainwater collection systems are the following:

1. a cover to prevent entry of animals or mosquito breeding
2. fencing or other security measures to prevent small children from falling in
3. state-by-state differences in laws regarding the use of rainwater

 Alternative water sources additionally play a role in xeriscaping by making use of almost every drop of water in an area to both aid the environment and conserve water use and costs.

Biodiversity Gardens

Land in temperate climates supports various gardens such as ornamental flowers, vegetables, herbs, or cacti. A biodiversity garden acts as another specialized type of garden that helps maintain diversity in nature. Biodiversity gardens contain plants selected to provide habitat, shelter, or feeding for reptiles, amphibians, insects, birds, small mammals, and even invertebrates and microbes. In some urban neighborhoods these gardens may present one of the few places where a healthy ecosystem can function.

In addition to providing for native plant and animal life, biodiversity gardens can serve a role in rescuing plant species that are slipping toward extinction. Two hundred years ago farmers grew a large variety of vegetable plants and fruit trees, but over time commercial farms reduced the number of varieties to make packing and shipping easier. Growers prefer plant and fruit varieties that mature quickly, resist bruising during shipping, and have a long shelf life. In the process of targeting these traits, many thousands of other varieties have become increasingly rare. The Public Broadcasting System (PBS) reported in 1998 that to save plants with a long history in North America, called heirloom varieties, “an increasing number of dedicated gardeners are growing these threatened plants and sharing the seeds with others. These ‘seed savers’ have rescued hundreds of varieties . . .” The naturalist Craig Tufts of the National Wildlife Federation explained in the PBS show, “When people open their eyes, they can be amazed at what they can find in their own backyards.” Biodiversity gardens offer an excellent way for a household to observe nature.

Planning and building a biodiversity garden adheres to the following steps:

1. Explore local open space and determine the types of bushes, shrubs, and plants that grow there.
2. Seek a natural location to plant the garden in a place where it will attract wildlife—near ponds, streams, meadows.
3. Plan vertically as well as horizontally by selecting climbing plants such as ivy or creepers or small trees and build a trellis if needed.
4. Provide water in a ground-level space and also in a raised birdbath.
5. Include plantings that provide hiding places for birds, reptiles, and small mammals.
6. Substitute organic fertilizers for chemical fertilizers and eliminate use of chemical pesticides.
7. Install raised nest boxes for birds and install nearby bat boxes.
8. Minimize trimming and clipping, but water often.

 The Royal Horticultural Society headquartered in London, England, suggests that the best way to assess whether a garden contributes to biodiversity is by watching for birds, bees, and butterflies. Birds indicate that the garden offers nectar, pollen, seeds, and insects and may possibly provide adequate nesting space for a new family of hatchlings. Birds also supply a food source for foxes and hawks. Birds and bats additionally act as effective insect pest control. Honeybees and bumblebees indicate that flowering plants and trees are breeding and producing pollen and nectar. The presence of other insects such as hoverflies and ladybugs indicates that pest control is working because these species eat harmful insects such as aphids. Butterflies contribute to the garden ecosystem because their larvae provide a protein source for birds, small mammals, and other insects.

 A good rule of thumb in answering the question of how well a biodiversity garden helps nature is to watch or listen for a variety of insect, reptile, amphibian, bird, and mammal life. Daytime and nighttime activity by a wide variety of species assures that the diverse plantings have successfully provided a space for nature to thrive.

Soil, Water, and Lawns

Natural ground cover vegetation such as wild grasses, clover, weeds, and small shrubs helps stabilize the land. Ground vegetation attracts wildlife that replenishes the soil with nutrients at death or by preying on other animals, which leaves body parts on the ground. Some wildlife aerates soil by rooting in search of prey or digging burrows. Natural ground vegetation and trees with strong root systems also conserve water by slowing runoff and evaporation. Despite all the benefits of natural vegetation, many people love the look of a yard blanketed with a green and trimmed lawn, called turfgrass. In some parts of the United States, the perfect lawn can be maintained only through extensive watering, fertilization, and chemicals.

Why do people continue to desire homogeneous expanses of lawn that look nothing like the vegetation that grows in nature? The British geog-

People waste thousands of gallons of water each year. Clean freshwater is a natural
resource that should be conserved like all other natural resources. Building designs and
plumbing devices are available to reduce water waste and in some cases to reuse gray
water, the wastewater from showers, sinks, and washers. Gray water can then be used
for landscape irrigation.

rapher Dennis Cosgrove suggested in his 1988 book The Iconography of Landscape that the desire for lawns rather than natural growth is a psychological choice based on how nature was depicted in the arts for centuries. For instance, European landscape paintings from the 17th century show natural land as parks and gardens. The famous gardens of Europe, Britain, and Australia followed this example so that people living in cities could enjoy nature by strolling through trimmed, shaped, and manicured plant life, often sidestepping water sprinklers! Nothing of course could be farther from how nature truly exists. Many people nevertheless have come to think of nature in a parklike sense and feel that natural wetlands, grasslands, and meadows look a bit too messy. Culture therefore has a significant bearing on whether a person chooses a natural landscape over a manicured landscape.

Manicured landscapes involve high-maintenance endeavors that do little to help the environment, mainly because of water waste. The EPA’s WaterSense program has highlighted the following factors in water use and its waste in manicured landscape upkeep:

1. People water lawns too often and for too long, oversaturating soil and plants.
2. Many irrigation systems overspray onto paved areas.
3. Weather-based sensors and controllers can reduce water waste on lawns by 20 percent.
4. Soil moisture sensors can determine the amount of water in the ground available to plants.

 Turfgrass lawns provide the benefit of reducing soil erosion, but their maintenance, lack of diversity, and thirst for water far outweigh that single advantage. Since eco-landscaping requires strict care in water use and reuse, a new type of natural landscaping has evolved for the purpose of maximum water conservation: xeriscaping. In xeriscaping, land contour, plant selection, and irrigation methods all coordinate for the purpose of minimizing water demand. (Xeri derives from the Greek word xero for “dry”; the word scape refers to any view or scene.)

 Xeriscaping professionals select native plants with an emphasis on the most drought-tolerant species. In some parts of the United States, such as the dry southwestern region, xeriscaping serves as a crucial water conservation tool. In addition to drought-tolerant plantings, shade trees take part in a xeriscape by preventing excess water loss through evaporation. In some instances, xeriscaping also needs soil amendments so that the natural soil holds water better and does not drain too quickly. Organic matter

The plants selected for a landscape should be native or adapted to the climate. Drought-resistant plants such as
these help reduce water waste. (A) red columbine (B) coral honeysuckle (Trees 4NC)

 and humus added to fast-draining soils retain moisture, and sand helps slow-draining soils drain faster and prevents rotting. Landscaping therefore offers homeowners a variety of techniques for conserving water.

Plants and Trees

Landscaping with native plants and trees relies on two principles. First, native vegetation requires less input from a landscaper or homeowner because the vegetation has already acclimated to the soil composition, water constituents, and climate. Second, diverse plant life provides a more stable environment than landscaping with a limited variety of plants. A diverse mixture of native plants and trees fosters a diverse mix of insects, birds, and predators, or in other words, a balanced ecosystem. The ecosystem’s animal life reduces pests, spreads seeds, pollinates, trims bark, thins out foliage, and recycles nutrients. Variety in vegetation therefore helps maintain animal diversity, which in turn promotes more plant diversity.

Despite the advantages of native trees and plants, people often prefer a manicured look to their property because they have become accustomed to trimmed and lush lawns with neat shrubbery. For this reason, eco- landscapers sometimes blend native vegetation with ornamental plants. For instance, large properties of more than two acres can accommodate both a natural section growing native vegetation and a more manicured section that mixes native trees and plants with ornamental varieties. Part of the property retains its wild appearance, and the other part contains trimmed clearings and periodic removal of underbrush.

Edible landscaping involves planting of
fruiting and vegetable plants in place of
lawn. The plants enrich the soil, reduce
erosion, and provide a sustainable use
of the landscape. By growing food at
home, gardeners decrease the fuel used
to drive to a market, and, in a small way,
home gardening decreases the energy
needed for transporting food around the
world. (iVillageGardenWeb)

Homeowners may also choose to take a step toward sustainability by creating an edible landscape, meaning a property containing native fruiting and vegetable plants. The Associated Press writers John Seewer and Doug Whiteman reported in 2008, “The idea goes back centuries, to times when people sustained themselves with food they grew on their own and filled every corner of their land with edible plants. But with the mass production of food, the practice gave way to manicured lawns.” There are more than 20,000 edible plants in the world comprised of seeds, stalks, petals, pollen, and roots in addition to familiar fruits and vegetables. The table on page 144 lists some of the most common types that can be used in their native environment as part of an edible landscape.

Edible landscapes can also make use of edible flowers that give color and aesthetic appeal to a yard. The following list summarizes the most common edible flowers used in landscaping today: alliums (leeks, chives, etc.), angelica, anise, arugula, borage, chamomile, chicory, chrysanthemum, clover, dandelion, hibiscus, jasmine, lavender, marigold, pansy, peony, rose, and violet. When growing any edible flower, landscapers should not use chemical pesticides, and they should choose native plants that contribute to the local habitat.

Ecological Architecture

Ecological landscape design must by definition blend a new structure’s design with the land. Architect Frank Lloyd Wright in fact stressed that structures are not built on the land but in the land to emphasize the connection between human-made structures and environment. Ecological architecture therefore goes hand in hand with ecological landscaping.

Ecological architecture has the following objectives for the purpose of building a connection between a new structure and nature:

• Buildings conform to a site’s natural ecology.
• Buildings maximize the use of natural materials.
• Materials and waste should be managed in a way that returns them to the Earth.
• Materials and wastes do not harm the environment.
• The architecture is based on renewable energy.
• Each building possesses a sense of place that is directly tied to the local environment.

 Nature is an overriding theme of ecological architecture, so houses built this way have certain features in common that seem to bring nature right into each room. These features are large windows, skylights, large doors opening onto natural stone patios or a garden, flowing natural water near or in the house, and an emphasis on sunlight during the day and moonlight and the Milky Way at night.

 In order to attain a feeling of cooperation between humans and nature, ecological architects create with form and function in mind, often by using Frank Lloyd Wright’s designs as models. Ecological architects also make use of sustainable materials, off the grid energy use, and they have recently begun to explore concepts of biomimicry. Ecological architecture creates designs for buildings that will emphasize the use of renewable resources, natural building materials, and nonfossil fuel energy, all for the purpose of reducing the building’s ecological footprint. The ecological footprint is the amount of Earth’s land area needed to supply the resources to sustain a person or an activity and dispose of the wastes.

Ecological architecture calls upon new technologies to help meet some of its objectives. The main technologies now being used in ecological architecture are alternative lighting methods, heat distribution, water conservation and reuse, and natural waste decomposition methods. Many of the clues as to how to accomplish these activities may already be part of human history. Ancient civilizations completed magnificent feats of architecture without the use of machinery or steel (but they did make liberal use of backbreaking manual labor). Nature offers its own set of examples on how to maximize lighting, distribute heat and cooling, ventilate, use natural water flow, and decompose wastes.

Frank Lloyd Wright

Frank Lloyd Wright (1867–1959) was born in Wisconsin but spent most of his early years and professional life in Chicago, Illinois. Wright had dreamed of becoming an architect since his youth, and, after studying civil engineering, he moved to Chicago in 1887 to work for architect Joseph Lyman Silsbee, where he drafted his first building, Unity Chapel. A year later Wright joined Chicago’s Adler and Sullivan Architects. Under his mentor, Louis Sullivan, who advocated the philosophy of blending form with function in architecture, Wright expanded his viewpoint to develop the idea of “Form and Function Are One.” With Sullivan as a main influence on his budding career, Wright continued designing buildings that had a style never before seen in American design.

Frank Lloyd Wright’s buildings in the United States contain several core features that have made them unique and collectors’ items in the world of architecture. The most common hallmarks of Wright’s designs are: emphasis on the horizontal plane; no basements or attics; no paint; low-pitched rooflines with deep overhangs; uninterrupted walls of windows; liberal use of skylights; large, stone fireplaces in the building’s heart; and emphasis on the use of natural materials, such as woods and stone.

As Wright’s career and designs progressed, he increasingly integrated nature into his buildings. Sloping roofs matched the slope of the hillsides; large doors and windows lessened the distinction between the indoors and outdoors; and flowing brooks ran under, around, and sometimes through a building. Wright likely became the first person to use organic to express a new way of developing and designing an object or even a lifestyle. “Organic buildings are the strength and lightness of the spiders’ spinning,” he remarked, “buildings qualified by light, bred by native character to everyone and married to the ground.” Wright probably never used sustainable in connection with his architecture, yet Wright’s designs provide excellent guides for present-day sustainable or green houses. Wright followed his own path to sustainability decades before it became fashionable and even necessary. By favoring natural materials, natural cooling and ventilation, and using landscape to create part of a building’s structure and support, Wright certainly contributed to today’s environmental engineering.

By the end of Frank Lloyd Wright’s life, he had developed 1,141 home or building designs and completed 532 of them. His designs and the philosophy behind them influenced architecture in North America, Europe, and Asia. Ten Wright-designed buildings were nominated in 2008 by the Frank Lloyd Wright Building Conservancy to be included on the World Heritage List of the most significant cultural or natural treasures. The United Nations Educational, Scientific and Cultural

Fallingwater in Mill Run, Pennsylvania, was designed by Frank Lloyd Wright. Built between 1936 and 1939 in
the Bear Run watershed in western Pennsylvania, the house contained features rarely seen in architecture at
the time. Portions of the house appear to float free over a natural waterfall—the house is built directly on
top of a stream—and the entire house is in harmony with the woods around it.

Organization (UNESCO) oversees the competition; the nominations and selections will take place between 2009 and 2019. The 10 buildings that have been nominated because they best demonstrate Frank Lloyd Wright’s scope, quality, and unique design are the following:

1. Unity Temple, Oak Park, Illinois (completed 1904)
2. Frederick C. Robie House, Chicago, Illinois (1906)
3. Hollyhock House, Los Angeles, California (1921)
4. Taliesin, Spring Green, Wisconsin (1925)
5. Fallingwater, Mill Run, Pennsylvania (1939)
6. S. C. Johnson and Son, Inc., Administration Building and Research Tower, Racine, Wisconsin (1936, 1944)
7. Taliesin West, Scottsdale, Arizona (1937)
8. The Price Tower, Bartlesville, Oklahoma (1952)
9. Solomon R. Guggenheim Museum, New York City, New York (1956)
10. Marin County Civic Center, San Rafael, California (1957)

 The sites listed here and hundreds of other Wright buildings continue to serve as study models in environmental and civil engineering, landscaping, and ecological design.

Landscaping with Nature

When landscaping with nature, eco-landscapers prepare a parcel of land so that a new building will behave as architects and the homeowners intend, but also reduce its effects on air, land, and water. To preserve air quality, the landscaper designs planting arrangements that prevent dust. Dust-preventing tactics consist of groundcover plants, such as low-growing evergreen shrubs or herbs, ground vines, or pebbles. The landscaper also considers ways to minimize noise from nearby roads or neighbors and reduce disturbance from city lights at night. To preserve the quality of the land, the design should retain much of the natural vegetation, restore ground cover to prevent soil erosion, and avoid landscaping that could lead to mudslides, flooding, or trees downed by severe storms. Water quality preservation can be accomplished by preventing erosion that pollutes streams with silt, retaining the natural course of streams, leaving wetlands undisturbed, and creating a natural buffer zone around flowing waters, lakes, or shorelines.

Biodiversity gardens filled with a variety
of native vegetation at varying ages and
heights made good artificial habitats
for birds, small mammals, reptiles, and
amphibians. This type of garden requires
clean freshwater in a pond or fountain.
Native vegetation gardens need minimal
care, and they will not lead to rodent
infestation as some people fear because
they draw a variety of predators: hawks,
owls, and foxes. (Oregon State University)

The table on page 136 highlights the main ways that environmental engineers who specialize in landscaping create space that works well for a new home and for the local environment.

Habitats, Inc., is an eco- landscaping company in Eugene, Oregon, that has promoted all of the methods listed in the table on page 136 for building landscapes that blend with nature. The

company expresses the following viewpoint: “Landscapes are part of a living ecosystem, exposed to the elements and forces of nature, and are therefore in a constant state of dynamic equilibrium in the cycles of growth and decay. Creating and maintaining healthy ecosystems reduces the need for intensive routine maintenance.” Eco-landscaping therefore has advantages beyond the ones mentioned here. That is, eco-landscaping reduces a property owner’s costs and labor because it reduces the need for applying chemicals, pesticides, fertilizers, intense watering, and—because the landscape blends with the natural contours of the land—the need to build retaining walls, drainage ditches, or other structures that try to hold back the forces of nature. The sidebar on page 138 “Frank Lloyd Wright” relates how one architect introduced the concept of designing with nature.

City residents can also participate in ecological landscaping with a bit of inventiveness. Some city townhouses and apartments include small backyards. Owners can plant these backyards with native shrubs and plants rather than cover the ground with concrete. One native tree fit into even a small yard helps to draw native birds, insects, and other life that bring nature into the city. Plant life additionally removes carbon dioxide (CO2) from the atmosphere, a process that aids the air quality of traffic-clogged cities. Some city dwellers with a serious commitment to the environment build permaculture farms inside their properties. A permaculture farm uses sustainable practices such as composting, rainwater collection, and cultivation of vegetables and fruits. Some city permaculture farms may even raise animals such as chickens if local ordinances allow it.
Cities would benefit from ecological landscaping because the trees and vegetation that are part of an ecological landscape help clean the air and regulate temperatures. But today’s metropolitan areas have lost most of their connection to nature so ecological landscaping may not be a practical undertaking. To return even a small parcel of land to the environment requires a landscaper to remove pavement, return streams to their natural shape and condition, and plant native vegetation. The brownfields program administered by the U.S. Environmental Protection Agency (EPA) and similar programs in other countries consist of voluntary agreements in which landowners return polluted property to safe use. Sometimes the owner works with the local community to return the cleaned-up brownfield to its natural condition. Once urban brownfields have been restored with natural vegetation and landscaping, they are called green spaces.

Traditional Landscape Design

Landscape design begins with a survey of a specific parcel of land, followed by mapping of all the physical features the surveyors have identified. These features include hills, gullies, trees, streams, ponds, and any preexisting structures, roads, or driveways. A landscaper then contours the land to accommodate any new building about to be constructed on the site.

A trimmed and fertilized lawn became
the hallmark of landscaping in the early
20th century. Green lawns appeal to
many people, but, unless the landscape
is carefully managed, a lawn breaks up
natural vegetation, destroys habitat,
wastes water, and often includes chemical
fertilizers that run off the lawn and
contaminate surface waters. Many lawncare
companies now use sustainable lawn
management by applying only organic
fertilizers and selecting grasses adapted
to the environment, so they need less
watering. (Taylor Made Lawncare Services)

Traditional landscaping for decades began by cutting down trees and bulldozing the site to make access easier for construction workers. Often landscapers used dynamite to break up large rock formations. They then hauled away surface boulders, filled ponds, and drained wetlands. Sometimes they lopped off the tops of trees to improve a view. These changes to the land were once thought to be enhancements to a property, but environmental engineers now understand that the greater the change made to a landscape, the greater the disruption to natural ecosystems. Ecological landscapers have now changed the way in which landscaping is done for three purposes: (1) preserving natural habitat, plants, and trees; (2) leaving as much natural contour in the land as possible; and (3) using the natural landscape to enhance the energy use of the new building.

Today’s ecological landscaping still has a need for heavy earthmoving equipment, but ecological landscapers make greater efforts to preserve natural hills and depressions, streams and wetlands, and trees. All landscaping has evolved so that today it incorporates the following aspects:

1. water, topsoil, and energy conservation
2. reduction of storm water runoff
3. horticulture of native plants
4. pest management that reduces the use of chemicals by using natural pest antagonists
5. nutrient replenishment of soils by methods other than chemical fertilizers
6. new plantings and gardens to restore habitat
7. waste reduction and recycling of construction wastes

 Landscapers who include these features in their work are called ecolandscapers. Unlike landscaping of just a decade ago, eco-landscaping makes every effort to include the natural geography and topography of the site to be altered. Eco-landscapers follow nature’s lead in order to preserve ecosystems and conserve energy.

Even landscapes that contain traditional features such as lawns, gardens with nonnative plants, and nonnative fruiting and flowering trees can be transformed into a more compatible fit with the surrounding ecosystem. Some homeowners have done this by replanting lawns with natural vegetation and replacing nonnative growth, such as a rose garden with a garden of native plants and shrubs. A landscape that in the past received major changes to its contour cannot be rebuilt to its original shape, but owners can take other steps to return the land to a natural state.

Ecological Landscape Design

Land degradation represents one of the biggest threats to the environment. The destruction of natural habitat by uprooting forests and grasslands disrupt carbon recycling and storage. New housing developments break up wildlife habitats, cloud streams with excess silt, and cause soil erosion. Even the best-planned developments disrupt nature’s landscape. Single houses built on undisturbed land produce similar harms to ecosystems, including the ecosystems that are almost invisible to people, such as soil ecosystems, the species living in foliage, and the microscopic life in nearby streams. Few people could miss the irony that comes from building an energy-efficient solar-powered home on a hillside that has been denuded of trees, bushes, and earth. In order to mesh the innovations of energy-efficient homes with nature, environmental engineers have begun to pay special attention to a new structure’s surroundings. For this reason, environmental engineering incorporates a component that considers land topography, climate, and natural vegetation. Ecological landscape design combines the task of coordinating a new building with its natural surroundings and remodeling the landscape to fit the new building in a natural way.

Today’s ecological landscape design has three main objectives: (1) minimize the disturbance done to the land during and after construction; (2) minimize all health risks to people and the environment due to the new construction; and (3) reduce construction wastes. At the end of a construction project that has worked within these guidelines, the new structure should function in harmony with the environment. As the theme of this book stresses, environmental engineering seeks to work in cooperation with nature rather than to find ways to subdue nature.

Energy from Nanotechnology

Energy-efficient electronics depend on some form of energy storage so that excess energy can be held for future use and not wasted. In fact power storage makes up one of the three main components of energy management for homes as well as vehicles: power generation, power transmission, and power storage. Lynn E. Foster, author of the book Nanotechnology: Science, Innovation, and Opportunity, opined, “If you can solve the problem of local storage, you’ve basically solved the whole problem. That’s because, by definition, the storage you need is local. You’ve got terawatts [equals one trillion watts or one billion kilowatts] of power moving into the grid. The biggest problem with renewable energy in general, and solar and wind in particular, is that they’re episodic and not dispatchable.” This means that the energy supplied on community power grids comes in pulses rather than in a steady stream, and utilities cannot dispense the energy in doses as needed. Foster continued, “You’ve got to have storage. Storing energy in batteries, capacitors, fuel cells, and some chemical systems like hydrogen depends on nanoscale interactions.” Nanoscale is a general term for the size of things that are no bigger than an atom or a molecule—a nanometer is one billionth of a meter. Nanotechnology is the science of working with nanoscale-sized devices.

Nanotechnology’s value to science lies in the observation that matter behaves differently at the nanoscale than it does on a larger scale. The DOE has explained this technology and its value: “All the elementary steps of energy conversion (charge transfer, molecular rearrangement, chemical reactions, etc.) take place on the nanoscale. Thus, the development of new nanoscale materials, as well as the methods to characterize, manipulate and assemble them, creates an entirely new paradigm for developing new and revolutionary energy technologies.” Nanotechnology is still in its

Engineers have been using nanotechnology to develop thin layers designed for generating an electrical current and producing light. The next step using nanoscale materials may be to convert solar power directly to light with a solid-state structure such as this one. Engineers also plan to embed tiny solar cells in window glass to produce electricity from sunlight. (Source: Paul Alivisatos, Lawrence Berkeley National Laboratory)

infancy, as scientists discover new behaviors of common materials when at the nanoscale level and find ways of applying this knowledge for practical uses. The following table provides a list of the main opportunities in nanotechnology for producing new energy-generation systems for electronics and other items.

Nanotechnology will likely help in the development of the following two energy conservation objectives: inventing future energy generation devices that perform in ways that current devices cannot, and finding new ways to catalyze reactions to minimize energy input and waste output. At present, ideas for new uses of nanotechnology have developed faster than actual methods have developed.

The Btu and the Kilowatt

The acronym Btu (or BTU) stands for British thermal unit. Energy utilities use two terms, Btu and kilowatt (kW) to describe energy and power; a Btu is a unit of energy and a kW is a unit of power. Energy equals the potential ability to do work or produce heat. By contrast, power is the rate at which work is done. The difference between energy units and power units can be expressed as follows:

1. A kilowatt is the rate of energy use at this instant.
2. Kilowatt-hours refers to the total amount of energy used over time.

 Therefore, utility companies, appliance companies, and fuel producers often relate the Btu to the kilowatt by transforming the expression for energy to an expression for power by the following conversion:

1 Btu = 2.9 × 10-4 kilowatt-hours (kWh)

(The Btu itself can be converted to a unit of power, the Btu-hour [Btu/h], though this term is less commonly used than kilowatt-hour.)

A person can visualize the Btu as the amount of heat required to raise one pound (0.45 kg) of water one degree Fahrenheit from 60°F to 61°F (15.6° to 16.1°C). Home appliances range from 5,000 to 50,000 Btu, and in the United States the population uses 100 quadrillion Btu (called Quad) in a single year.

Most home electrical devices use very small kilowatt amounts that can also be measured in watts, or one-thousandth of a kilowatt. Electrical devices typically range from 15 to 500 watts (0.015–0.5 kW). An appliance that provides a power value in amps, for amperes, rather than watts can be converted as follows:

number of amps × 120 volts = number of watts

By understanding the Btu and kilowatt-hours, homeowners can accomplish two objectives: gain a better idea of how appliances consume energy, and understand their rate of energy use in order to monitor energy savings.

Sensors and Feedback

Sensors that work with feedback systems easily and automatically conserve energy. Energy sensors monitor the use of electrical and heat energy within a room or an entire building. Sensors can be used in two different ways to conserve energy. First, they monitor a building’s peak and nonpeak times of energy use and so identify the periods in which a structure puts more or less stress on a community’s power grid. Second, on-off sensors such as motion sensors turn indoor or outdoor lights on when they detect motion and off when the area is no longer being used to reduce energy waste.

A wood stove generates heat without
using electricity. Stoves and fireplaces
conserve a house’s solar power and avoid
the need to draw from the municipal
power grid. Wood is a type of biomass
that produces an equivalent amount
of Btu as crop wastes, which are also
combusted for energy production. (Jotul)

Sensors in combination with feedback systems provide even better control of energy use because a feedback system tells a building’s residents how efficient they are in using energy. A sensor- feedback system contains two components: the detection unit called a transmitter that may be attached to an electrical or gas utility meter, a water meter, or a thermometer, and the display unit located inside the house, which receives wireless signals from the transmitter. Sarah Rich wrote for the online environmental magazine WorldChanging, “It’s one of those telling facts of human nature that when we are being monitored, our behavior changes.” Just like a speedometer in a car, people self-monitor when they receive helpful information. “The same holds true in households,” Rich explained, “where inhabitants can be made immediately aware of their energy consumption. If you can see your pennies piling up on account of a light you left on in the bathroom, you can bet you’ll remember to turn it off.” These so-called smart sensors offer one of the simplest ways to manage energy use.

New systems make energy savings even easier for people to save energy. Hotels or homes can be equipped with key cards that contain information on the indoor heating, cooling, and lighting systems. As a person enters a room, inserting the card into a small slot box near the door, lights and other systems turn on to make the environment comfortable, with heat, air-conditioning, or ventilation. The person simply removes the card from the slot when they leave, and the systems readjust to energy-saving mode. Sensors and automatic on-off switches are inexpensive, and the electricity savings make up for the price in a short period of time.

Light

Scholars have puzzled for centuries over the nature and the meaning of light. Light has been thought of as streams of particles since the time of the ancient Greeks. Though no one had actually seen the light particles, scientists assumed the particles simply moved too fast for the human eye to detect, so humans perceived light as a beam or as a field of light. In the 1600s Christian Huygens described light as having more characteristics of waves than of particles. For the next 300 years leading to studies by Albert Einstein, scientists built upon this theory that light behaved like a wave.

Today physicists describe the complex concept of light either as the particle theory or the wave theory. The particle theory states that light consists of beams of photon particles, which Einstein defined as distinct energy packets. The wave theory, also clarified by Einstein, suggested that light is made up of light waves. In fact, light behaves as both particles and waves, but physics students tend to study light in terms of waves because it is easy to understand wave behavior and apply it to light’s characteristics. Lightbulbs serve as a convenient source of light that follow all the rules listed here. The most familiar characteristics of light are the following:

1. Light reflects off surfaces at the same angle at which it strikes the surface.
2. Light waves do not need a medium such as water to travel through (sometimes this is expressed as the ability of light to travel through a vacuum).
3. Light waves radiate from their source, so light is referred to as radiation.
4. Light waves’ energy is in the form of electric fields and magnetic fields, explaining why light can be described as electromagnetic radiation.
5. Light occurs in a range of wavelengths that begin as invisible (to humans), progress into a visible range called the visible spectrum, and end again with invisible waves.

 Light emanates from both incandescent bulbs and CFL bulbs with very little visible difference, but each light source works differently. Any light source produces light by energizing atoms, which causes the atoms’ electrons to behave in an excited state. Electrons are negatively charged pieces of an atom. Eventually, the electrons fall back from their excited state to their normal state in the atom, and this transition from higher to lower energy releases extra energy in the form of a light photon. Incandescent bulbs energize atoms by heating them, which explains why these bulbs become very hot when they are turned on. Fluorescent bulbs use electricity rather than heat to energize atoms. In fluorescent bulbs, an electric current flows from one pole to an opposite pole. During this flow, the current’s electrons bump into mercury (in vapor form) atoms along the path. The energized mercury atoms emit ultraviolet light as they return to a low-energy state; the ultraviolet light hits a compound called phosphor, which then emits visible light.

 Environmental engineers treat light as other scientists do, that is, light is a form of energy and in this form the universe transmits energy from one place to another. Solar homes equipped with light collectors (called photovoltaic cells) convert light energy into other forms of energy, usually electric and heat. Meanwhile humans depend on light’s interaction with their ocular system (the eyes and the nerves connecting them with the brain) to interpret their surroundings. Light has certainly been taken for granted by nonscientists in their everyday routines, but this abundant resource is becoming one of the most promising options for shifting away from dependence on fossil fuel energy. Light energy may soon become the main energy source for cars, boats, appliances, and telecommunications in addition to new solar homes.

Home Energy and Heat Storage

The United States wastes almost 85 percent of all the commercial energy it takes off the power grid. People waste by not conserving energy in their daily activities: leaving lights on, letting television play with no one watching, or running small laundry loads. Faulty appliances and inefficient machines and vehicles waste additional energy. Energy waste also occurs naturally due to the second law of thermodynamics that states that some energy is always lost when being converted from one form to another. Considering these opportunities for potentially usable energy to escape, engineers now design structures that have several different systems for conserving, recapturing, and reusing energy, whether the energy is in the form of light, electricity, or heat.

New homes contain many improvements in energy management that older houses from the 1950s through the 1980s did not possess. Insulation, seals, doors, windows, and roofs have all been improved for the purpose of retaining household energy, usually in the form of heat.

A new type of construction called a superinsulated house contains features so efficient in holding heat that sunlight, appliances, and residents provide enough heat to keep the indoors warm. Superinsulated houses contain some or all of the following features: (1) very thick insulation with R values of R-40 to R-60, meaning they have high thermal resistance and so prevent heat transfer across their boundaries; (2) triplepaned insulated glass in windows; (3) few or small north-facing windows; (4) airtight seals; and (5) an air-to-air heat exchanger. Air-to-air heat exchangers are appliances that transfer heat across a barrier from warm, stale indoor air to cool, fresh outdoor air. By this process, heat exchangers ventilate the indoors and capture and reuse heat to prevent heat waste. Superinsulated houses are also likely to contain thermal mass materials that hold heat.

Older houses often waste energy as heat loss that can never be recaptured, but even these houses can be improved with simple fixes. The following steps help transform an energy-wasteful house into an energyefficient house:

1. plug leaks around windows, doors, in cracks, and in holes
2. replace old insulation
3. replace old windows with insulated, energy-efficient windows
4. install a heat exchanger or a heat pump (removes warm air and replaces with cool air)
5. use energy-efficient appliances and lighting
6. replace large tank water heaters with a tankless instant water heater
7. install good seals on doors to attics and unheated basements and keep doors closed

 Homeowners need not wonder how well they do in saving energy because each home has a meter that shows electricity and heating fuel usage. The basics of energy measurements used by energy utilities are described in the sidebar on page 126 “The BTU and the Kilowatt.”

American architect Edward Morse
designed a wall in the late 1800s in
which a sheet of glass covered the wall’s
masonry. This design increased heat
transfer from outside to the inside of
the building and reduced heat loss. In
the 1960s French designer Félix Trombe
improved on the concept, and the wall
now bears his name. The Sun’s heat
passes through a doubled-paned window
and warms the masonry next to it. The
masonry then releases the heat into the
interior. (MultiwallSystems.com)

Learning from Electric Eels

Biomimicry may be considered a science of emulation in which engineers build systems for human use based on the way nature builds its systems. This science looks at nature in a new way, focusing not on what humans can extract from nature but rather what they can learn from nature.

In 2008 researchers at Yale University developed tiny artificial cells for the purpose of powering medical implant devices. They used the energy-generating cells called electrocytes in electric eels as their model. The chemical engineer Jian Xu explained, “The electric eel is very efficient at generating electricity. It can generate more electricity than a lot of electrical devices.” (A clue to this ability lies in the eel’s biological name, Electrophorus electricus.) The engineering team’s problems in generating energy the same way as an eel does were twofold: understanding how the electrocyte works and learning to build a similar electrical device.

Electric eels have three different energy-generating systems: two high-voltage systems are used for defense and for stunning prey and a low-voltage system helps in navigation. Disc-shaped electrocytes run all three of these systems. The electrocytes stack up like a series of watch batteries in the eel’s organs so that when each fires and produces a low to moderate amount of energy, the cumulative effect is a large energy pulse.

Non-firing electrocytes hold a negative charge inside the cell by constantly pumping positive sodium ions (Na+) out and allowing positive potassium ions (K+) to naturally diffuse out through the cell membrane. An ion is an element missing electrons or possessing extra electrons. To fire the electroctyes the eel’s brain sends a message to nerve cells, which stimulate one side of each electrocyte. The side of the electrocyte receiving this nerve impulse becomes stimulated in a process called depolarization. The nerve-side of the electrocyte becomes depolarized an instant before the far side of the electrocyte depolarizes. This occurrence leads to a temporary one-way flow of ions or an electrical charge. The eel’s charge of up to 600 volts comes from the synchronized depolarization of about 200,000 electrocytes.

Yale’s researchers built small discs based on the electrocyte’s depolarization action, which they called a “bio-battery.” The quarter-inch- (0.64-cm) thick bio-batteries contain the following two components: (1) artificial membranes based on the electrocyte membrane that sets up inside-outside charge differences, plus (2) proteins that mimic the ion channels in real membranes. So far, the artificial electrocytes have been made to generate 30–40 percent more power than the natural electrocyte. The researchers plan to line up the bio-batteries in several stacks of about a dozen to produce enough electricity to power medical prostheses such as retinal implants.

Though these plans and devices are scarcely off the drawing board, tiny power generators have opened similar possibilities for using bacterial cells or even mitochondria—the energy-generating component of eukaryotic cells—as mini–power plants. The task involves only the willingness to apply basic engineering concepts to designs produced by nature.

Lighting

People spend most of their lives indoors in industrialized countries, so lighting becomes an important drain on a power grid. Lighting comes in two forms, natural sunlight and electrical, and each of these can be managed in a way that increases the overall energy efficiency of a home.

The most efficient use of natural sunlight is called daylighting. Daylighting integrates natural light with electrical light to create the best indoor lighting conditions as well as to save energy. Daylighting usually involves the following four main structures for maximizing the amount of sunlight that enters a structure:

1. light pipes—roof to ceiling tubes, about 13 inches (33 cm) in diameter, that can light about 200 square feet (19 m2) of space with sunlight
2. skylights—large, rectangular rooftop windows
3.  clerestory windows—narrow horizontal windows set high into walls
4. light shelves—horizontal platforms that redirect light hitting a large south-facing window so that the light penetrates deeper into a room

Daylighting is an energy-saving technique that reduces the need for electric lights during the day. Many techniques aid daylighting. A clerestory or a light shelf each reflects light deeper into the house’s interior. Special glazes on wall surfaces also help reflect light into rooms.

 The daylighting structures mentioned here provide benefits to the home in addition to bringing in more light. For instance, clerestories opened in summer let hot air out, and if they are made of well-insulated glass they hold in warm air in the winter. Light shelves expand the available light to make electrical lighting almost unnecessary during the day, and they reduce glare. The Lawrence Berkeley National Laboratory has estimated that light shelves can expand the indoor daylight zone 2.5 times the window height.

Improved morale and even health may be added benefits that come from daylighting. Students in classrooms and office workers have better attention, memory recall, and productivity in daylighted rooms than people in rooms with only artificial light. Building designer David Hobstetter wrote in a well-researched 2007 article in Real Estate News, “Our lives have become increasingly sedentary and cloistered over the past few decades, with the rise of the digital age. As a species, we now pass the vast majority of our time indoors . . .” Hobstetter attributed increased stress, fatigue, absenteeism, and even work-related illnesses to poor indoor working conditions, including a lack of natural light. A Toyota employee put it in simpler terms when talking with the Los Angeles Times reporter Roger Vincent, “The [natural] lighting is easier on the eyes and on the nerves. It’s pleasant and feels more productive.” Daylighting therefore has psychological advantages to complement health and energy-saving benefits.

The compact fluorescent lightbulb
demonstrates that not all achievements
in environmental engineering need be
complicated to have a positive effect
on the environment. By redesigning
normally long, straight fluorescent
lighting into a compact size about the
same as an incandescent bulb, engineers
introduced an energy-saving product for
homes and offices.

Electrical lighting serves as a substitute for natural sunlight and offers the following advantages over sunlight: (1) it can be turned off; (2) it can be dimmed or made to produce high intensities; (3) it can be selected in different colors; and (4) it provides light in places where sunlight cannot reach. The best way to improve energy efficiency in electrical lighting is to replace all standard incandescent lightbulbs with either compact fluorescent (CFL) lightbulbs or halogen lights. Incandescent bulbs emit only 10 percent of their energy as light and 90 percent as heat, meaning they are very inefficient at converting electrical energy into light energy. CFL bulbs cost more than incandescent bulbs, but they last 10 to 20 times longer and use 75 percent less energy. The following table summarizes the impact of CFL bulbs on energy savings by using the U.S. Environmental Protection Agency’s (EPA) and Department of Energy’s (DOE) joint Energy Star online calculator.

Each incandescent bulb replaced by a CFL bulb reduces the CO2 emissions from power plants by several hundred pounds over the bulb’s useful life. If each U.S. household replaced one light, CO2 emissions would drop by more than 1 trillion pounds (454 billion kg). Halogen lighting does not save as much as CFL bulbs, but halogen lighting is still about 50 percent more efficient than incandescent lighting. All types of electrical lighting can be made more energy efficient by using light sensors to dim or turn off lights on bright days and timers to turn off lights automatically.

The U.S. Congress has voted to follow the lead of the European Union, Australia, New Zealand, Japan, and Brazil in banning the sale of incandescent lightbulbs beginning in 2012. According to the plan, the United States will have phased out all incandescent lightbulbs by 2014.

Smart Appliances

The core idea of sustainable living pertains to energy generation, use, or waste. Environmental engineers have investigated opportunities for energy saving inside homes and other buildings. One of the most familiar opportunities comes from Energy Star appliances that have been designed and certified to ensure they conserve energy compared with older appliances. The next step in energy savings will be in the emergence of smart appliances, which consist of home appliances, such as refrigerators or washing machines, equipped with computer chips that sense energy usage and regulate the energy consumption of the appliance. For example, a smart refrigerator may contain a chip that tells the compressor to go into a rest mode when the unit’s light (which indicates an open door) stays on for longer than a minute. This action prevents electricity waste during the refrigerator’s use.

Other appliances can employ similar rest modes in which the appliance partially shuts off to save energy. Freezers, washers, dryers, water heaters, dishwashers, ranges, and microwave ovens would be helped by this technology. Most homes in the United States have all of these appliances, and most of them run at the same time. By adding up all the homes on a single block, then totaling the households in a moderate-sized town, it takes little imagination to guess the effect these appliances have on a community’s power grid when they all run concurrently.

This unique smart appliance combines a toilet with a washing machine. The wastewater from the washing machine goes to the toilet tank for flushing. (Peazyshop.com)

The next generation of homebased smart appliances will probably connect by Internet to the municipal power grid to reduce power drains during the heaviest usage periods. This type of appliance–power grid connection provides two advantages: overall energy conservation and alleviation of demand on grid infrastructures during peak times when they are most vulnerable to breakdown. These same appliances may also sense when the power grid is at its most stressed and automatically go into rest mode. A household filled with smart appliances would balance the community’s power use and waste automatically for the homeowner.

Electronics in addition to large kitchen and laundry room appliances have also been planned for automatic energy regulation. Televisions, video equipment, home entertainment systems, telephones, and computers all draw energy even when they are turned off. Many people have learned to unplug these devices when not in use, but new smart electronics will make this unnecessary and be more dependable in conserving energy.

Smart appliances resemble any innovation in technology in that their costs will be high at first and then become more affordable as the public purchases them. Rob Pratt, a program manager at an appliance testing laboratory, remarked to MSNBC in 2007, “If this becomes cheap enough, even your coffeemaker can help the grid out.” The MSNBC report concluded that if the majority of homes in the United States converted to smart appliances, the country would save about $70 billion in new power plant construction and power distribution costs in 20 years. By turning energy-saving control over to appliances, people may receive an overall benefit in energy and money savings.

Solar Homes

Solar power for homes and other buildings uses either an active or a passive form. Active solar devices collect energy from the Sun and store it or move it by the use of electrical controls, pumps, and fans. Passive solar power, by contrast, does not rely on any mechanical help. Passive solar

Houses with solar panels such as this one drastically cut the electricity they take from the municipal power grid.
(Gray Watson and Rosemary McCrudden)

energy employs windows, walls, and doors to collect, store, and distribute solar energy without the need for any other energy input. Passive systems and active systems conserve heat in the winter, but they also reject excess solar heat in the summer.

The main principle of solar energy relates to the concept of gain, which is the amount of usable solar energy that a structure captures. Solar homes can be designed to contain one of the following three types of gain:

1. direct gain—sunlight enters south-facing windows and strikes walls and floors, which store the energy as heat
2. indirect gain—solar heat strikes the home’s outside wall and is stored between the outer and inner wall from which it radiates as heat
3. isolated gain—a structure, such as a solarium, separate from the main house captures and stores solar energy as heat in its masonry

 Regardless of the type of solar gain a house has been built to use, designers and environmental engineers pay attention to five basic elements of solar energy systems, described in the following table.

 Solar homes distribute energy by three different means: conduction, convection, and radiation. In conduction, heat energy moves through solid matter by exciting molecules as it spreads through the matter. For example, a lit stove boils water in a pot because the metal pot conducts the stove’s heat energy to the water. Convection consists of heat circulation through

Solar energy can be equally valuable outside traditional neighborhoods, such as this passive solar farmhouse in
New York. (Green Rabbit Farm)

liquids or gases rather than solids. A lighted fireplace, for instance, heats a room by convection. Radiation may be solar or infrared radiation, both associated with the light spectrum, or nuclear radiation used in nuclear power plants. Solar radiation consists of the movement of heat through air from warm objects to cooler objects, such as a solarium warming up when exposed to bright sunlight. Infrared radiation consists of a warm surface transferring heat to a cooler surface. This type of radiation works when a person is chilly and snuggles under an electric blanket to warm up.

Solar homes contain design elements and building materials that aid in heat distribution by any of three different mechanisms: radiation is absorbed, reflected, or transmitted. Large glass windows transmit plenty of sunlight to the indoors. Glass absorbs only 10–20 percent of solar radiation and transmits the rest. The 80–90 percent of solar radiation that enters a house can then be absorbed by materials that absorb and hold heat better than others. Opaque solid materials such as stone floors and walls absorb 40–90 percent of the radiation entering a house; darker materials absorb more heat than lighter colored or white materials that reflect much of the radiation.

Passive solar energy works best if a building has been designed to make maximum use of the sunlight for heating and energy production. This diagram illustrates the ways in which passive solar energy collection is optimized— large windows, reflective surfaces—and stored in thermal mass materials, such as concrete and brick, which absorb heat then gradually release it.

The best-designed solar homes possess an attribute called thermal capacitance, meaning the capacity of materials to store heat. The following materials predominate in new solar homes because they have a high degree of thermal capacitance: stone, masonry, concrete, brick, tile, and water. These materials are named thermal mass materials and may also be thought of as insulating materials because they hold their temperature once they have heated up or cooled down. Thermal mass is so effective that in cities where hundreds of brick and concrete buildings fill each block, the buildings raise the outside temperature 2–8°F (1.1–4.4°C), an event known as the heat island effect.

Many solar homes offer all the luxuries of conventional homes (modern fully equipped kitchens, storage space, patios, porches, pools, fireplaces, skylights, fountains, and gardens), and they have become the most desirable type of new homes in many parts of the United States.

The energy expert Bernadette del Chiaro of the alternative energy advocacy group Environment California told the Los Angeles Times in 2007, “[House] builders are seeing that they’ll get more buyers coming to their developments when they have solar. They sell like hot cakes.” Solar homes in fact outsell homes in some communities such as San Jose, California. Solar homes nonetheless account for only a little more than 5 percent of all homes in California, a state that seeks to reach 50 percent solar in all new housing by 2015. Other smaller communities have similar goals of making all new public buildings solar-powered.

Solar devices installed on homes work best to save energy when used in combination with thermal mass building materials, as mentioned. Other alternative building materials sell at moderate cost, but the use of these materials requires a break from traditional methods of construction. Michael Funk helped design his solar-powered house in California’s Sierra Nevada. He admits that not all alternative materials were as readily available at building supply businesses as conventional materials. “When it comes to building with alternative and sustainable materials and using local artists and craftspeople, you can run into resistance,” he told Natural Home and Garden magazine in 2006. “You have to keep asking, keep digging, keep pushing. The products are out there. When you meet resistance, just push back. There’s a way to get everything you want. It just takes more work and persistence.” The table on page 114 lists common components and materials preferred for building new solar homes.

Existing houses and buildings can be switched to solar power with the installation of solar panels on the roof and connections to the house’s main energy input. The task can be done in a few days to weeks depending on the size of the building and number of panels to be installed. Many homeowners have been hesitant to install solar energy because of solar’s current high price. For the present, homeowners need about 50 years for the energy savings of solar energy to repay the installation cost.

Homeowners cope with three disadvantages to solar power in addition to expense: (1) periodic cutting of overhanging tree branches that block the sunlight from reaching rooftop collectors; (2) surrounding tall buildings that may make solar energy use difficult or impossible; and (3) solar collectors on the house that change the house’s appearance. Solar homes in very cold climates or places with heavy cloud cover may need a backup generator or occasionally draw energy from

the local municipal supply. Solar homes also offer many advantages that outweigh some of the concerns. First, they use an energy source that is free, sunlight. Second, they produce no carbon dioxide (CO2) emissions, and, third, produce no or little air, water, or noise pollution. Fourth, rooftop solar collectors install quickly, and, fifth, collectors do not upset the landscape. Finally, the energy cost savings drop to near zero or even below zero. In some U.S. states, energy utilities reimburse homeowners with solar systems that put energy back onto the community’s energy grid, also called a power grid.

Solar power has become mainstream throughout Europe, Australia, and the United States because it uses the simple principle of letting nature supply energy for human use. Ecosystems have always managed energy this way, but human civilization long ago adopted a different means of making energy: producing it by burning energy-containing fuels in engines. Environmental engineers are beginning to return to studying nature for clues about how to run systems at maximum efficiency from natural materials, the principle behind biomimicry.

Energy Efficiency through the Years

The Sun has supplied the Earth with a never-ending source of energy since time began. As human life developed, the Sun remained the only energy source for human use unless a lightning strike happened to cause fire. The earliest humans probably ran from fires with other animals, but at some point in history they began to appreciate the heat that came from it. Fires caused by lightning strikes ran their course, burned out, and left humans again in darkness and cold, waiting for the next strike to rekindle the phenomenon. Perhaps humans learned to anticipate the next strike with the knowledge that light and warmth would return with it.

Humans’ ability to start fires on their own represented a tremendous step in civilization because people had harnessed energy for the first time. Early humans started fire by rubbing two pieces of flint together, and they kept the fire going with the easiest fuel at hand—wood. A constant and controlled fire enabled people to live a less nomadic life, and small settlements congregated around fires for heat, light, and cooking. Meanwhile, residents of these settlements used the energy supplied by flowing water in streams and rivers to carry away wastes.

After mastering fire and making use of water’s energy, Phoenician sailors 3,500 years ago learned to harness the wind to power their ships. Two thousand years later people combined waterpower and wind power to develop waterwheels and windmills to grind grain and run sawmills. As the centuries unfolded, oils that bubbled up from the sea, coal, and natural gas all served as fuels for heat and making light. Though these fuels dominate the industrialized world today, until about 150 years ago wood remained the main source of energy, as it still is in many underdeveloped parts of the world.

Throughout the 20th century and the early years of the 21st, oil, coal, and natural gas served as society’s leading sources of energy. But prolonged use of these fossil fuels has led to water and air pollution, destruction of habitat, and global warming. The 21st century will make greater use of six energy sources that avoid the use of fossil fuels: solar, wind, wave and tidal action, geothermal, hydrogen, and biomass. Of these energy sources, solar energy has provided the first breakthroughs in shifting a fossil fuel–based society to one that depends on nonfossil fuels. The California sustainability expert Geof Syphers said of the new solar communities on the rise, “This is really about lifestyle. We want to make sustainable living easy for people. We want to make it appealing.” Like fire, wind, and water harnessed by the ancients, steam engines and combustion in the Industrial Revolution, and modern nuclear energy, new energy sources are always appealing because they enable technology to take a major step forward.

Solar communities like that described by Syphers and other renewable energy sources have been supplying an increasing portion of total energy consumption in the United States, but these alternative energies still account for only 7 percent of total energy consumption. (Petroleum supplies 40 percent, natural gas supplies 23 percent, coal accounts for 22 percent, and nuclear energy supplies the remaining 8 percent of total U.S. energy consumption.)

The solar power industry divides its business into two segments: photovoltaic power, which converts sunlight to electricity, and thermal solar power, which turns sunlight into heat. Photovoltaic systems have grown rapidly in the industry for the past 10 to 15 years, and they make up a large portion of renewable energy’s 3 percent annual increase in growth. Thermal solar power rose for the 10 years up to 2006 as oil prices increased, then declined as oil prices declined. The outlook for the global solar industry continues to be encouraging, especially because many new solar technologies have been emerging for the purpose of increasing solar power’s efficiency and decreasing its cost.

Energy-Efficient Electronics

Energy efficiency means the use of as little energy as possible to receive a benefit. For example, a kayaker knows to deliver even, smooth strokes to guide the kayak through the water rather than making choppy and exaggerated strokes, which power the kayak but waste energy. Both types of paddling take the kayak to shore, but the first method conserves energy so that the kayaker has stamina left over. Any piece of equipment can be designed with the same goal in mind: to perform a job with a minimum amount of energy wasted.

A switch to sustainable business begins by identifying all energywasteful activities and replacing them with energy-efficient activities. Office workers and homeowners receive help in doing this from energy utility companies that provide information on how to save electricity, natural gas, or heating oil. Today, offices and homes contain seven main areas of design that aid energy efficiency: (1) overall structure design; (2) landscaping; (3) electricity use; (4) insulation and sealing; (5) lighting; (6) heating and cooling; and (7) water heating. This chapter discusses electricity use and the electronic products that supply lighting, room heating and cooling, and water heating.

Today electrical engineers develop electronics that meet people’s needs while also reducing overall energy demand on the environment. The chapter begins with the history of how society harnessed power for its various inventions through the centuries. solar energy for homes; energy-efficient appliances; lighting; heating; and communications. It also contains sidebars on the attributes of light as an energy source and how people measure energy. The chapter builds on the main theme of this book by explaining how engineers develop new technologies by learning from nature. Finally, it explores novel ideas in energy conservation: the use of sensors and feedback systems and the role of nanotechnology in energy production.

Sustainability and Business

The Washington State University department of ecology has explained sustainability as “meeting the needs of the present without compromising the ability of future generations to meet their own needs.” This goal could as easily apply to businesses as it does to the environment. Any activity that consumes resources so fast that it cannot sustain itself has created a trap that becomes difficult to escape. Today’s large corporate business models ignore this basic concept by planning constant growth into the future even though the world’s resources will not last forever. For businesses to be truly sustainable so that future generations can benefit from their products, business leaders must develop a long-term plan for the environment the same as they do for future profits.

In the mid-1800s in Butte, Montana, a generation of industrialists grew wealthy by dominating the silver, gold, and copper resources in the region. These copper barons, William Clarke, Marcus Daly, and F. Augustus Heinze, became the most powerful people for as far as one could see from Butte’s town limits. But the metals did not come out of the ground forever, and by the middle of the 1900s the copper barons’ fortunes and Butte’s future plummeted. How difficult is it to draw a parallel between Montana’s mining industry and today’s oil industry? Though the Energy Information Administration (EIA) has predicted that new technologies will find another 76 billion barrels of oil in the United States by 2025, no one knows for certain the volume of oil still available. That is because the science of locating and measuring the size of as-yet undiscovered oil reserves contains a wide margin of error. Scientists do know that regardless of the volume underground, the oil will someday run out. Global warming that results from burning fossil fuels such as oil may well choke the planet long before the oil disappears. It is therefore in everyone’s best interests to adapt to sustainable practices as soon as possible.

The most daunting challenge for businesses’ conversion to more environmentally sound decisions comes from the business community itself. Bjorn Stigson, president of the World Business Council for Sustainable Development, remarked in 2008, “They [business leaders] know they cannot solve these problems alone, but have to work with others to develop solutions, even when this means learning to listen to their critics and those who oppose their actions.” Each business’s customers might hold the greatest power in getting industry leaders to listen.

Perhaps slow, steady improvements in business might give communities the best chance of success in converting to sustainability. Drastic changes often present big risks for business, but smaller steps toward sustainable practices balance environmental needs with business needs. For example, many companies have already reconfigured their activities to save on raw materials, reduce waste, conserve water, and conserve energy. These small steps have proven to be easy to implement and have a big impact over time. New business methods such as just-in-time production and more efficient distribution chains already help build profits while offering benefits to the environment. Meanwhile, companies have been expected to follow laws on emissions, waste discharges, and hazardous waste management and reporting. The next phase of decisions may incorporate some of these innovations:

1. conversion from coal-fired power plants to renewable energy sources such as solar
2. use of only alternative fuel for shipments
3. participation in waste recycling programs or transfer of waste to other industries
4. new technologies for handling water that cools production machinery and for returning the water safely to the environment
5. waste-to-energy processes
6. conversion from chemical synthesis methods to biological methods
7. redesign of packaging to reduce waste
8. redesign of products to biodegradable materials
9. conversion of offices to use of recycled products and alternative materials and energy

 In business, the decisions that will make these innovations possible are referred to as front-end decisions, because they must be planned before the production process is designed, built, and operated. End-of-the-line activities, by contrast, refer to activities that try to make things better after all the production has been completed: disposing of wastes, installing devices to clean gaseous emissions, filtering discharge water to remove most of the pollutants, and taking back unsold products so they do not end up in landfills. The success of sustainability in business revolves around eliminating end-of-the-line activities by putting more emphasis on front-end decisions. Today, almost all major U.S. cities have sustainable business networks that help businesses implement sustainable practices. At this point in history, industries large and small have no excuse for sidestepping sustainable practices.