Energy Efficiency and Renewable Energy

Four widely used devices waste large amounts of energy:

• Incandescent light bulb: 95% is lost as heat.

• Internal combustion engine: 94% of the energy in its fuel is wasted.

• Nuclear power plant: 92% of energy is wasted through nuclear fuel and energy needed for waste management.

• Coal-burning power plant: 66% of the energy released by burning coal is lost.

REDUCING ENERGY WASTE AND IMPROVING ENERGY EFFICIENCY

WAYS TO IMPROVE ENERGY EFFICIENCY

CAFE (Corporate Average Fuel Economy)

General features of a car powered by a hybrid-electric

engine

WAYS TO IMPROVE ENERGY EFFICIENCY

• Fuel-efficient vehicles powered by a fuel cell that runs on hydrogen gas are being developed.

• Combines hydrogen gas (H2) and oxygen gas (O2) fuel to produce electricity and water vapor (2H2+O2 2H2O).

• Emits no air pollution or CO2 if the hydrogen is produced from renewable-energy sources.

FUEL-CELL VEHICLES

Fuel Cell Automobiles

• Operational costs are less• Electric motors have very few moving

parts• No pollutant emissions• Quieter• Reduced oil consumption

ELECTRIC VEHICLES

• Accredited more than 25,000 building professionals in energy and environmental design

• Established energy and environmental design guidelines

• Certifies buildings for meeting guidelines

U.S. GREEN BUILDING COUNCIL’S LEADERSHIP IN ENERGY AND

ENVIRONMENTAL DESIGN (LEED)

• Surrounding area has porous pavement bricks to replenish aquifer

• Solar cells provide about 10% of energy

• Solar hot water heating system

• Roof garden• Concrete building

blocks filled with foam• Water-free urinals

CHINA’S MINISTRY OF SCIENCE AND TECHNOLOGY BUILDING

• Roofs covered with plants have been used for decades in Europe and Iceland.

• These roofs are built from a blend of light-weight compost, mulch and sponge-like materials that hold water.

GREEN ROOFS

We can heat buildings by orienting them toward the sun or by pumping a liquid such as water through rooftop collectors.

HEATING BUILDINGS AND WATER WITH SOLAR ENERGY

Passive solar heating system absorbs and stores heat from the sun directly within a structure without the

need for pumps to distribute the heat.

PASSIVE SOLAR HEATING

Direct Gain

Summer sunHot air

Warm air

Super-insulated windows

Winter sun

Cool air

Earth tubes

Ceiling and north wall heavily insulated

Windows facing South

We can cool houses by:• Superinsulating them.• Taking advantages of breezes. • Shading them.• Having light colored or green roofs.• Using geothermal cooling.

COOLING HOUSES NATURALLY

Ground Source Heating and Cooling: Ground source heating and cooling can be done almost anywhere in the United States using a geothermal heat pump, a highly efficient renewable energy technology that takes advantage of the constant temperature of the earth beneath the surface. The heat pump transfers heat stored in the Earth or in ground water into a building during the winter, and transfers it out of the building and back into the ground during the summer. In other words, the ground acts as a heat source in winter and a heat sink in summer.

Large arrays of solar collectors in sunny deserts

can produce high-temperature heat to spin

turbines for electricity, but costs are high

USING SOLAR ENERGY TO GENERATE HIGH-TEMPERATURE HEAT AND

ELECTRICITY

Parabolic trough solar thermal electric power plant located near Kramer Junction, California (uses thermo oil Heat Transfer Fluid)

Solar cookers – focus sun’s energy to heat (radiation)

PRODUCING THERMAL HEAT

Photovoltaic (PV) cells can provide electricity for a house of building using solar-cell roof shingles

PRODUCING ELECTRICITY WITH SOLAR CELLS

Solar cells can be used in rural villages with ample

sunlight who are not connected to an electrical

grid

PRODUCING ELECTRICITY WITHPHOTOVOLTAIC SOLAR CELLS

Konarka Technologies

Trade-Offs

Solar Cells

Advantages Disadvantages

Fairly high net energy Need access to sun

Work on cloudy daysLow efficiency

Quick installation

Need electricity storage system or backup

Easily expanded or moved

No CO2 emissions

High land use (solar-cell power plants) could disrupt desert areas

Low environmental impact

Last 20–40 years

Low land use (if on roof or built into walls or windows)

High costs (but should be competitive in 5–15 years)

Reduces dependence on fossil fuels DC current must be converted

to AC

• Wind power is the world’s most promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases.

• Much of the world’s potential for wind power remains untapped.

• Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands.

PRODUCING ELECTRICITY FROM WIND

Wind turbines can be used individually to produce electricity. They are also used interconnected in arrays on wind farms

PRODUCING ELECTRICITY FROM WIND

MagLev Wind Turbine Industries in Arizona

• Uses magnetic levitation to limit friction between moving parts

• 3.3 mph wind

• Creates 20% more energy

• Safe for birds

• Produce power around 1 penny per kilowatt hour

Bahrain World Trade

Center

Growth in Global Wind Power Installed Capacity

Trade-Offs

Wind Power

Advantages Disadvantages

Moderate to high net energy Steady winds needed

Backup systems needed when winds are low

High efficiency

Moderate capital cost

Low electricity cost (and falling)High land use for wind farm

Very low environmental impact

No CO2 emissions Visual pollution

Quick constructionNoise when located near populated areasEasily expanded

Can be located at sea

Land below turbines can be used to grow crops or graze livestock

May interfere in flights of migratory birds and kill birds of prey

The scarcity of fuelwood causes

people to make fuel briquettes from cow dung in India. This

deprives soil of plant nutrients

PRODUCING ENERGY FROM BIOMASS

Wind will blow through the middle where a turbine is

located

The World’s greenest skyscraper – Pearl River Tower in China

• 71-story; 2.3 million square feet

•Rainwater collection system

•Solar water to provide hot water for the building

•Use wind patterns to spin wind turbines

•Photovoltaic panels on outside “skin” of building

•Raised floor ventilation – keep building cool