Electricity is vital to our everyday life. We assume that there will continuously be enough for us, but this is not always true. Each power plant has an upper limit to the amount of electricity it can generate. If the demand is greater than the supply, then there are brownouts and blackouts. As our population grows, the demand for electricity increases.

New power plants can be built to help meet the demand. Each power plant requires a source of input energy that is then converted to electricity. This conversion is most often done by creating steam that is driven through large, fan-like turbine blades. This causes the blades to rotate, and spin the shaft on which they are connected. The other end of the shaft is then used to generate electricity using the rotation and magnetic fields.

The input energy can be fuel, such as coal, oil, or natural gas. Burning the fuel heats the water to create the steam for the turbines. Fossil fuels are non-renewable energy resources that create a variety of pollution when burned. Solar energy is also used to heat water and create steam for the turbines. Since it does not have to be burned, there are no bad by-products or pollution. However, solar energy is not very efficient for this process. The energy given off from the splitting of atoms during nuclear fission is another input source for creating the steam. Nuclear power generates radioactive by products during the fission process. Geothermal energy from within the earth can be used to heat the steam that spins the turbine blades. There are very few locations around the world where geothermal temperatures are high enough to be used as the input energy.

There are also ways of generating electricity without using steam to spin turbine blades. Hydropower uses water that is falling to spin turbine blades. Usually a dam is required to maintain the water height, and this impacts the water life in the area as fish can no longer travel upstream.

Have students complete the Preparation Worksheet for homework to gain a better understanding of the nation's energy problems and the types of energy resources available.

Part 1: Establish the Baseline - Who needs electricity, and how much do they need?

1. Divide the students into groups and pass out Worksheet 1 to each group. Lead a discussion about who uses electricity. Which type of user (home, transportation, businesses, and industry) do the students think are the largest consumers of electricity? Which group uses the least amount? What is the justification of the students for how these compare?
2. Have each group estimate on Worksheet 1 the percentage of electricity used by the four types of users.
3. Compare the predictions of each group. As a class, decide if you want to use the average value from the predictions for all the groups, or if each group wants to use their own predictions. These estimates will be contrasted to actual numbers gathered by the groups.
4. If you have access to the internet, have the groups research what the actual average breakdown is for each of the groups. If internet access is not available, or time does not permit, use the values provided on the Leaders Resource Page attached.
5. Have the groups use the personal electricity data they have brought with them. What is the average kW/hr use for the group? Share this information to determine kW/hr average for the entire class.
6. Discuss the resulting average and how it might vary over the course of a day, month, and year. Is there an overall group consensus on a peak demand time for electricity? Does it vary based upon the type of user? Does it vary based upon the location in the country?

Part II: What are our resources for creating electricity?

1. Explain that the teams have been hired by the HMT Corporation to estimate the power requirements of a new hospital when it operates at full capacity. The hospital is being designed to accommodate 500 patients plus all the support staff. Given that a hospital is like a small community with similar power needs for the basic four groups (home, transportation, business, and industry) determine the resources of your locality that can be used for the hospital power plant. What are the impacts of your recommendation?
2. Reinforce that the hospital is being considered for a neighboring community with resources similar to yours. Discuss where the electricity in your town comes from. What is the input source of energy? Do you have other options for energy that are readily available? You may wish to create a list as the students suggest them.
3. Present the students with the current town/hospital statistics provided on the Leader's Resource Page OR provide them with values that more closely represent a local community in your area.
4. Change the groups so that there are now 2 or 3 larger groups. Have each group begin working as individual consulting reams for the HMT Corporation. Pass out Worksheet 2 that outlines their objectives, and Reference Sheet 1 with energy conversion efficiencies.
5. Have each student group present their proposal, including a discussion of why they selected the energy source they chose. Do they feel that their suggestion is worth pursuing? Lead a discussion on the trade-offs required for any of the choices. Every one of them has some impact on the environment.
6. Discuss how the student approached the problem as engineers.