Energy Efficiency and Renewable Energy
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