Energy Efficiency & Renewable Energy Resources

Transcription

1 Energy Efficiency & Renewable Energy Resources

2 Discuss with your table partner: What is the difference between energy conservation and energy efficiency? Give an example of each.

3 Improving the percentage of total energy input that does. If 1.2 million households replaced a 60 watt incandescent bulb with a 15 watt compact fluorescent bulb for light used 4 hrs/day, ~89,600,000 kwh/year would be saved enough energy for 7,000 homes.

4 We could save as much as % of all the energy we use by improving energy efficiency. Four widely used devices that waste energy Incandescent light bulb Motor vehicle with an internal combustion engine Nuclear power plant Coal-fired power plant Energy Inputs 85% 8% 4% 3% System U.S. economy Nonrenewable fossil fuels Nonrenewable nuclear Hydropower, geothermal, wind, solar Biomass Outputs 9% 7% 41% 43% Useful energy Petrochemicals Unavoidable energy waste Unnecessary energy waste

5 Inefficient incandescent bulbs produce a large amount of heat.

6 Video on Energy Efficient Light Bulb Legislation Lighting uses 19% of the world s energy There are 4.4 billion incandescent bulbs in the US.

7 Discuss with your table partner: Determine a list of strategies to improve energy efficiency.

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9 Energy Efficiency Net energy efficiency: the net efficiency of the entire energy delivery process is determined by the efficiency of each step in the energy conversion process.

10 PBS Video on Smart Grid Technology

11 Cogeneration (Combined Heat and Power- CHP): the production of two useful forms of energy from the same fuel source Example:.

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13 Attic Hang reflective foil near roof to reflect heat. Use house fan. Be sure attic insulation is at least 30 centimeters (12 inches). Bathroom Install water-saving toilets, faucets, and shower heads. Repair water leaks promptly. Kitchen Use microwave rather than stove or oven as much as possible. Run only full loads in dishwasher and use low- or no-heat drying. Clean refrigerator coils regularly. Basement or utility room Use front-loading clothes washer. If possible run only full loads with warm or cold water. Hang clothes on racks for drying. Run only full loads in clothes dryer and use lower heat setting. Set water heater at 140 if dishwasher is used and 120 or lower if no dishwasher is used. Use water heater thermal blanket. Insulate exposed hot water pipes. Regularly clean or replace furnace filters. Outside Plant deciduous trees to block summer sun and let in winter sunlight. Other rooms Use compact fluorescent lightbulbs or LEDs and avoid using incandescent bulbs wherever possible. Turn off lights, computers, TV, and other electronic devices when they are not in use. Use high efficiency windows; use insulating window covers and close them at night and on sunny, hot days. Set thermostat as low as you can in winter and as high as you can in summer. Weather-strip and caulk doors, windows, light fixtures, and wall sockets. Keep heating and cooling vents free of obstructions. Keep fireplace damper closed when not in use. Use fans instead of, or along with, air conditioning.

14 Discuss with your partner: Most sources of energy on Earth originate initially from the sun s energy. On the next slide identify types of energy that originate from the sun and 2 that do not originally come from the sun.

15 Renewable Energy Resources Originally Energy from Sun: Energy Independent of Sun:

16 A passive solar & superinsulated design is the cheapest way to heat a home in regions where sunlight is available more than 60% of daylight hours. Solar Energy Passive solar heating Sunlight is captured directly within a structure Heat is

17 Passive Home Design /09/26/business/energyenvironment/26smart.html?e mc=eta1&pagewanted=print

18 Solar Energy Active solar heating solar collectors absorb solar energy & a supplies the building s space or water heating needs

19 Rooftop Solar Hot Water on Apartment Buildings in China

20 Pros Active & Passive Solar solar energy is free net energy yield is high for passive & moderate for active technology is well developed & easily installed Heating does not emit polluting or greenhouse gases Cons solar collectors are ugly to some people active systems are costly

21 Solar Energy: Producing Electricity Ways to Generate Electricity from Sunlight 1. Photovoltaic cells (solar panels) solar energy converted into electrical energy by photovoltaic cells sunlight striking atoms creates an electrical current electrical energy can be stored in batteries for use when the sun is not shining

22 Single solar cell Boronenriched silicon Junction Phosphorusenriched silicon Roof options Panels of solar cells Solar shingles Fig a, p. 415

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24 TRADE-OFFS Advantages Fairly high net energy yield Solar Cells Work on cloudy days Quick installation Easily expanded or moved No CO 2 emissions Low environmental impact Last years Low land use (if on roof or built into walls or windows) Reduces dependence on fossil fuels Disadvantages Need access to sun Low efficiency Need electricity storage system or backup Environmental costs not included in market price High costs (but should be competitive in 5 15 years) High land use (solarcell power plants) could disrupt desert areas DC current must be converted to AC

25 Solar Energy: Producing Electricity Ways to Generate Electricity from Sunlight 2. Concentrated Solar Thermal (CST) Solar collectors reflect light. And are.

26 Hydroelectric dams Hoover Dam

27 Video: Hydropower

28 Grand Coulee Dam Built ft high Required 12 million cubic yards of concrete (Fun Fact: enough concrete to make a 4 ft. sidewalk that wraps around the equator twice) Currently produces enough power for ~ in 11 states.

29 607 ft high, 1,200 towns and villages flooded during construction Chinese government says in addition to providing needed energy will help control flooding on Yangtze 18,200 Megawatts

30 Three Gorges Dam Video (2006)

31 Pros No emission of greenhouse gases High net energy yields Technology well-developed, inexpensive once in place Cons Dams Alters downstream habitat: reduces to downstream habitats water which can result in warmer water less dissolved oxygen due to higher temperature and less mixing. Dams interfere with fish runs Requires abundant water & large elevation differences Water supplies are often seasonal In arid areas, loss of H 2 O in reservoirs due to evaporation

32 Pros unlimited source of energy at favorable sites moderate to high net energy yield easy to build & expand emit no pollutants or greenhouse gases

33 Producing electricity from wind

34 Solutions: Wind Turbine and Wind Farms on Land and Offshore Advantage of offshore sites: winds less turbulent Review of weather to explain why ocean winds more consistent: Wind is caused by :.

35 Cons economical only in areas with steady winds are necessary since winds are not always steady ( energy source) mass production takes up a great deal of land space noise pollution may interfere with

36 Video- Largest Offshore Wind Farm in England Video- The Battle over Cape Cod Wind Farm

37 Using water heated from volcanic activity to create electricity.

38 The Krafla Geothermal Power Station in Northern Iceland

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40 Video on Geothermal Energy for Electricity

41 Pros: No greenhouse emissions Plentiful supply in some areas Moderate net energy yields Iceland

42 Cons: Scarcity of easily accessible sites Extraction of water can cause subsidence of land (land can sink) Costly in all but most concentrated sources

43 TRADE-OFFS Geothermal Energy Advantages Very high efficiency Moderate net energy at accessible sites Lower CO 2 emissions than fossil fuels Low cost at favorable sites Low land use and disturbance Moderate environmental impact Disadvantages Scarcity of suitable sites Can be depleted if used too rapidly Environmental costs not included in market price CO 2 emissions Moderate to high local air pollution Noise and odor (H 2 S) High cost except at the most concentrated and accessible sources

44 Geothermal Heat Pumps: The ground temperature. Geothermal pumps move a fluid through underground tubes that will be heated in the winter and cooled in the summer.

45 Geothermal Ground Source Heating/Cooling Video