Energy Efficiency and Renewable Energy. G. Tyler Miller’s Living in the Environment 14 th Edition Chapter 18. Bell Ringer. What is energy efficiency? Describe three ways you could increase the energy efficiency of the house in this picture. What is energy efficiency?.
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Energy Efficiency and Renewable Energy G. Tyler Miller’s Living in the Environment 14th Edition Chapter 18
Bell Ringer • What is energy efficiency? • Describe three ways you could increase the energy efficiency of the house in this picture.
What is energy efficiency? Energy efficiency is the measure of the useful energy produced compared to the energy converted to low quality--- usually heat. Using energy to do work, not produce heat.
What is energy conservation? Implementing new technology to do same work using less energy. • Heating homes more efficiently • Driving more efficient cars • Lightning spaces more efficiently SAVES $$$, produces less pollution, reduces CO2
Energy Conservation • 84% of commercial electricity is wasted in U.S. • 41% of energy is automatically wasted due to 2nd Law Of Thermodynamics • 43% is wasted unnecessarily
What are Life Cycle Costs? Initial Cost plus the lifetime cost. Some energy efficient models may cost more up front, but save money in the long run. Civic Hybrid vs. Conventional Gas
Net Energy Efficiency Measure of how much useful energy we get from energy resource after subtracting the energy wasted. How much energy you get out given ALL the wasted energy.
Ways to Improve Energy Efficiency • Cogeneration • Efficient electric motors • High-efficiency lighting • Increasing fuel economy • Alternative vehicles • Insulation • Plug leaks
How can industry save energy? • Cogeneration – combining heat and power systems • Improving electric motor efficiency (consumes 1/4th of energy) • Improving light fixtures
Hybrid Cars • Hybrid electric-internal combustion engine Hybrid-electric cars are powered by a battery and a small ICE that recharges the battery. Fig. 18-9 p. 385
Fuel Cell Cars Fuel cell cars run on hydrogen and produce little pollution. Combine hydrogen and oxygen to produce electricity and water vapor. Ford Focus Fuel Cell Car
GM’s prototype future fuel cell car. No engine noise, no pollution, no greenhouse gasses.
Electric Cars An electric car is an automobile that is propelled by one electric motor or more, using electrical energy stored in batteries or another energy storage device. Electric motors give electric cars instant torque, creating strong and smooth acceleration. Tesla Charging Stations
How can we Design More Efficient Buildings? Chicago’s Sears Tower uses more energy in a day than a city of 150,000 Atlanta’s Georgia Power Company uses 60% less energy than other buildings it size.
How can we Design More Efficient Buildings? Super insulated house: • Costs 5% more to build • Can use 90% less energy for heating and cooling Green Roofs: • Plants or gardens on roof help insulate from heat in summer and cold in winter
An infrared photo showing heat loss (red, white and orange) around windows, doors, roofs.
Use Efficient Windows Double pained, insulating windows cost more, but can save money in the long run.
Heat House More Efficiently Using the most efficient heating system available. Some natural gas furnaces can reach 85-98% efficiency
Heat Water More Efficiently There are several new technologies to heat water more efficiently: • Tankless, instant heaters • Well insulated tank
Use Energy Efficient Lighting and Appliances Microwaves, refrigerators, washers, driers, lights all come with energy star labels ¼ of electricity bill is lighting
Cut Off Electrical Devises Not In Use When not using lights, computers, TV’s and other electrical devises they should be turned off.
Complete Good Energy Stewardship Worksheet • Make a list of ten steps you can practically in your home take to reduce your energy use.
Bell Ringer • How many types of renewable energy can you think of? List them. • As we move away from reliance on fossil fuels in the future, describe how you see that transition taking place. (i.e. What will cars and gas stations be like? Where will your electricity come from? Will you have to sacrifice any of the things you enjoy today?, etc…) Include at least three specific details.
Using Solar Energy to Provide Heat • Passive solar heating: absorbs and stores heat from the sun directly within the structure *Has been used for thousands of years. *In the Northern Hemisphere, south facing windows receive the most solar energy. http://www.youtube.com/watch?v=lobSCweC2Nk
Using Solar Energy to Provide Heat Active Solar: absorbs heat energy from sun by pumping heat absorbent fluid through collectors. *Great for hot water heaters in warmer climates *Solar collectors, usually mounted on a roof, capture the sun’s energy.
Using Solar Energy for Electricity Solar energy can be converted directly into electricity using PHOTOVOLTAIC CELLS (PV) or “Solar Cells” Sunlight energizes electron to flow in a semi conductor producing an electrical current
Photovoltaic Cells Sunlight falls on a semiconductor, causing it to release electrons. The electrons flow through a circuit that is complete when another semiconductor in the solar cell absorbs electrons and passes them on to the first semiconductor. http://www.youtube.com/watch?v=0elhIcPVtKE
Using Solar Energy for Electricity http://www.findsolar.com/index.php?page=rightforme Solar Cells can be incorporated into roofing and windows. High costs are expected to fall Currently only supply 0.05% of world electricity
Renewable Hydropower • Hydroelectric energy is electrical energy produced by falling water. • Hydroelectric energy accounts for 20% of the world’s electricity.
One modern trend is micro-hydropower, which is electricity produced in a small stream without having to build a big dam. The turbine may even float in the water, not blocking the river at all. Micro-hydropower is much cheaper than large hydroelectric dam projects, and it permits energy to be generated from small streams in remote areas.
Reviewing the Trade-offs of Hydropower Dams Fig. 15-9 p. 313
Tidal Power A tidal power plant works much like a hydroelectric dam. As the tide rises, water enters a bay behind a dam. The gate then closes at high tide. At low tide, the gate opens and the water in the bay rushes through, spinning a turbine that generates electricity. http://www.youtube.com/watch?v=tSBACzRE3Gw
Although tidal energy is renewable and nonpolluting, it will not become a major energy source in the future. • The cost of building and maintaining tidal power plants is high, and there are few suitable locations. Tidal Power
Wave Power Using the constant wave action along shorelines to produce power. • Advantages • The energy is free – no fuel needed, no waste produced • Not expensive to operate and maintain • Can produce a great deal of energy • Disadvantages • Depends on the waves – sometimes you’ll get loads of energy, sometimes almost nothing • Needs a suitable site, where waves are consistently strong • Some designs are noisy. But then again, so are waves, so any noise is unlikely to be a problem • Must be able to withstand