*Energy: The Issues and the Science
Featured Course – Energy: The Issues and the Science
Can driving a hybrid car or turning down your heat really make the US less dependent on foreign oil? Why does our society consume so much energy and what percentage of that energy goes to energy production itself and why is that percentage increasing? In this course you’ll gain an understanding of the fundamental concepts of energy generation and flow as chemical, biological, and physical phenomena. You’ll also examine the difficult policy, technology and economic issues surrounding the production and use of energy.
It will surprise no one that the use of high-density energy sources provides the base on which our modern civilization is built (fossil fuels are high-density energy sources). And for citizens of the United States, with per capita energy usage among the highest in the world and with much of that energy coming from fossil fuels, it is equally clear that the current pattern of energy use is unsustainable over the long term.
Starting with the chemical, biological, and physical principles underlying our more common concerns with miles-per-gallon and electric bills you’ll delve into energy issues including the economics of energy production, how public policy effects energy usage, the environmental cost of energy consumption, and new technologies with the potential to support a sustainable energy policy.
Featured Activity: Electricity, Circuits, and Home Energy Usage
Students in this course complete a series of exercises designed to build understanding of the practicalities of generating, storing, and using electricity. Starting with a detailed analysis of home electric usage, students learn the basics of electric circuits using simulations, and then using a small hand-cranked generator, photovoltaic electric cells, batteries, and a multimeter –all supplied as part of the course materials– move to learn first-hand abou the generation, storage, and measurement of electricity.
Home Energy Consumption (activity from the course)
The home energy consumption model is a spreadsheet you’ll use to learn how much electricity you use for various activities in your home and how much that electricity costs you. The home energy diagram and spreadsheet are linked below and you should download the spreadsheet and save a local copy before starting. The spreadsheet is compatible with Microsoft Excel 2000 (or later) and you can also use OpenOffice Calc or any other spreadsheet capable of opening files in the Excel 2000 XLS format.
Start the activity by studying the house energy diagram. The model (the spreadsheet) is tied to this diagram but the diagram won’t exactly represent the space you live in so you’ll have to adapt the model to your home or apartment. The diagram is intended to help you categorize the energy usage in your home and you may want to print it so you can write notes as you examine the devices in your home and determine how much electricity each one uses.
There are a number of ways to know how much electricity a device uses. The easiest is to look on the device and find the label that says how many watts it consumes under normal use. For larger appliances with service guides you will usually find detailed information on the energy usage in the service guide. You can also estimate the amount of electricity consumed by various devices and appliances using generic guides found on the Internet. This website, from the U.S. Department of Energy is a good source for this type of information. Another approach, one that is rapidly gaining in popularity, is to use a device that measures the actual usage of electrical devices and appliances. These measuring devices come at different levels of sophistication (and price) but one popular model is called the Kill-a-Watt. The Kill-a-Watt it is available at many hardware stores for around $40. To use the Kill-a-Watt you plug it int a wall outlet and then you plug the device to be measured into it. Many a first time user of this device has been shocked to discover how much power some devices use, even when turned off!
Beyond listing the electrical devices you have and how much power they use, your goal for this exercise is to account for all the electricity used in your home. The completed the model (adjusted to fit your situation) will calculate your total electrical usage for a month. You can then compare this number to your actual electric usage found on your electric bill. If your electric bill is included in rent, but you have access to your electric meter, you can take a series of readings off the meter (3 readings at 10 day intervals is a good approach) and use that average to estimate your total usage.
Either way, finish up by comparing your actual usage with the usage calculated using the model. You may be surprised to learn how much of your electric usage goes to what is called the “phantom load” or “vampire power loss” in your home. That is electricity being consumed by appliances that are on but not in use. Elimnating and reducing this phantom load is an easy way to reduce your energy usage and costs.