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MINI PROJECT FREE See pages 32-37 for a free techdirections’ Mini On-Demand Classroom Project (Regular price $2.95) In addition to Mini Projects, the On-Demand Classroom Projects line includes over 150 full-size projects for only $6.95 each! Written by teachers for teachers, On-Demand Classroom Projects not only make learning fun for your students, but allow them to better understand how technology relates to the real world. Available in a wide variety of subject areas, from applied academics to woodworking. Order online and use them today! Simply duplicate and use for as many students—and for as many times—as desired. Our high-quality activities save you time and are priced with teacher budgets in mind. Projects include teaching tools such as procedures, vocabulary words, quizzes, photos, illus- trations, and much more. Check them out today! www.techdirections.com/projects.html www.techdirections.com POWER & ENERGY 31
FREE Mini-Project: Electric Power—Decisions for the Future
Phillip L. Cardon and John Preston
MOST of us take electricity for granted until it isn’t there. But when a storm knocks down the power lines, we suddenly realize how many of our daily activities depend on abundant and relatively low-cost electricity.
When we educate tomorrow’s voters and leaders, we must give them a perspective that is in part based on the past. In this article, we look at the past 25 years of electricity consumption in the United States and consider the implications for the near future. We also discuss some strategies for energy conservation.
Once students begin to work with energy conservation, they often continue to try to conserve energy. This activity will encourage them to have more awareness of their energy consumption and to think of ways to help conserve precious—and limited—resources.
References
Electric Power Monthly (March 2002). Monthly energy report. Report from the Energy Information Administration, Office of Coal, Nuclear, Electric and Alternate Fuels, U. S. Department of Energy, Washington, DC, 20585.
Salem Electric Company (2002). Understanding your electric meter. Retrieved May 15, 2002, from www.salem electric.com/guide/your_meter.html Tennessee Valley Authority (2002). Reading that mysterious meter on the side of your house. Retrieved May 15, 2002, from www.energyright.com/meter/meter.htm
U. S. Census Bureau (February 14, 2002). Population Projections Program. Retrieved May 15, 2002, from www.Census.gov/population/projections/nation/summary/npt1. txt
United States Department of Energy, Energy Information Administration. (August 2001) . Electric power annual 2000 (Vol 1). Retrieved May 15, 2002, from www.eia. doe.gov/emeu/aer/txt/tab0812.htm
United States Department of Energy, Energy Information Administration. (August 2001) . Electric power monthly, March 2002 update. Retrieved May 16, 2002, from www.eia.doe.gov/cneaf/electricity/epm/epm_sum.html
MOST of us take electricity for granted until it isn’t there. But when a storm knocks down the power lines, we suddenly realize how many of our daily activities depend on abundant and relatively low-cost electricity.
Electricity Usage
Many people think we now do a good job conserving electricity. Many appliances use much less than they did in the 1970s, when the OPEC (Organization of Petroleum Exporting Countries) oil embargo brought the issue of energy dependence to the forefront of national attention. At that time, a national program of low-cost energy audits provided information to millions of homeowners.
Due to some changes in regulations, a significant amount of electric power is now produced by nonutilities. Some of that power comes from previously wasted heat. Industrial operations that have a lot of waste heat now produce electricity with that heat. They either sell the electricity to a utility or send it on to another factory using the utility’s power line.
Yet in spite of our efforts to conserve energy and make use of previously wasted heat, the amount of electricity consumed in the United States has increased every year. (During this time the population has also increased, so it’s not entirely clear how we are doing as individuals.) Let’s look at how the amount of electric energy consumed compares with the increase in population.
In Fig. 1, electric energy (United States Department of Energy, Energy information Administration, 2001) is measured in tens of billions of kilowatt-hours and the population (U.S. Census Bureau, 2002) is measured in millions. We chose these units of measurement to allow comparison of the columns representing electricity and population. As you can see, the electricity produced has increased faster than the population. If we divide the amount of electricity produced by the population, we get Fig. 2. This figure shows that our conservation efforts have not reduced the amount of electricity we use. We have not even reduced the amount of electricity we use on average per person!
Two trends reinforce each other. First, individuals consume more electricity each year and, second, the population grows each year. According to the U.S. Census Bureau (2002), in this country there is a birth every 8 seconds and a death every 14 seconds. We also have one person immigrate to this country every 33 seconds. The net effect is that we add one person to our total population every 12 seconds.
The average person consumes 13,800 kilowatthours of electricity per year. This figure includes all the electricity used in our factories and businesses to produce the goods and services we consume, as well as our home electricity consumption.
By 2011, the U.S. is expected to have an additional 21 million people. If we try harder than we ever have before, and stop the increase in personal consumption, we would still have to build 13,800 kWh of generating capacity for each of those 21 million people. That amounts to 290 billion kWh.
A large generating plant can produce 1,000,000 kWh of power. If it runs 85 percent of the time day and night for a year, it can produce 7.45 billion kWh. If we divide the 290 billion kWh we will need for our increased population by the 7.45 billion kWh a large power plant can produce, we find that we need to build 39 more large power plants in the next eight years. If we use the same power sources for those plants that we have in the past, they will produce more greenhouse gasses and sulfur emissions at a time when we are trying to reduce both.
The area over which we have the most personal control is conservation. The following gives instructions on meter reading and a related experiment which will help you gain awareness of positive steps you can take to conserve electricity. It shows how to measure the amount of electricity used in a home on a typical day. You can compare that amount with the electricity consumed when conservation practices are applied.
Electric Power Usage: Part 1—Meter Reading
There are two basic types of meters, the digital meter (Fig. 3) and the dial meter (Fig. 4). The digital meter is very easy to read. The numbers displayed show the exact number of kilowatt hours used.
The dial meter takes a little more work to read and understand. There are five dials on this meter with numbers from 0 to 9. The 0 is at the top of each dial. The numbers go around the face of the dial counterclockwise on some and clockwise on others, usually alternating between clockwise and counterclockwise from left to right. When reading the dial meter, start with the dial on the far left and move to the right. Record the number that the hand has just passed. In Fig. 4, the dial on the far left shows the ten thousand kilowatt-hours and the dial on the far right shows the single digit kilowatt-hours.
If a dial’s hand is directly on a number, look at the next dial to the right. If the dial on the right shows the hand has passed zero, then record the number that the dial on the left points to (see Fig. 5). The dials in Fig. 5 show the reading of 70.
If the hand of the dial on the right has not passed zero, then record the last number that the dial on the left has passed. (See Fig. 6.) The dials in Fig. 6 show the reading of 69.
Electric Power Usage: Part 2—Tracking the Results of Conservation
1. Research to determine steps you could take to conserve electricity. Some possibilities: .. Turn off or unplug appliances, lights, clocks, and so forth, when not in use.
Set the thermostat no higher than 65° in cold weather and no lower than 75° in hot weather.
Replace incandescent light bulbs with fluorescent light bulbs.
Reduce the temperature on the water heater thermostat.
Clean the coils under and behind the refrigerator.
2. Devise a specific energy conservation plan. Ask your parents for permission to implement your plan and talk to family members about helping with its implementation.
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