Did you know that besides the sun, there are nine other ways to make electricity? It's a good thing, too, because people want more and more of it. They're trying hard not to waste electricity, but they're also trying to do more things with electricity. The Gross Domestic Product (GDP), which measures how many products and services our country makes , is one way to measure the economic health of our country (refer to graph 1). If the GDP goes up, it means people are doing better, generally, in their lives. The U.S. electricity line graph 1 goes up with the GDP line on graph 1, because electricity is used to make lots of products and provide services . The graph also shows that all kinds of energy, not just electricity, help make lives better.

If you plotted data (put information in graph form) for the GDP and electricity for developed countries like Japan, Germany and the United Kingdom, you'd find that the lines would increase together, like those for the United States. The GDP and electricity lines don't look the same for developing countries like India and China. Unlike developed countries, developing countries don't yet have as many electricity generating projects (which use fossil fuels and renewable energy sources) nor as many transmission and distribution lines to deliver the electricity to people.

As you explore various different places around the world on our web site, it's important for you to know that not all countries are able to make, deliver and use as much electricity as we do in the U.S. Even in this country, some people's houses are not connected to wires on power poles. You shouldn't be surprised to discover that people in the Appalachian Mountains, Australia, Latin America or China live differently than you.

This web site shows you how much electricity has been used in the U.S. in the past, as well as how much more electricity we're going to need in coming years. The Energy Information Administration keeps track of data so the Department of Energy (DOE) can help predict future use. The 1997 and 1998 Power Pie chart shows that most electricity was made from coal (refer to graph 3), but all energy sources were used to help make sure that no one went with out the power they needed. The 1974 Power Pie (refer to graph 2) has the same slices, but they're different sizes from the ones in the 1997 Power Pie. Twenty-five years ago, coal produced the most electricity, but all of the energy sources were used, even if they weren't used as much as coal. Twenty-one years from now, the Department of Energy predicts that we'll need a lot of energy to make electricity and, again, most of it will come from coal (refer to graph 4). However, every source of energy will need to be used so we all have enough electricity.

What would have happened if we didn't burn coal and didn't use the wind, the sun, nuclear power plants or natural gas to make electricity? There's a really good chance, especially if we didn't use coal, that you wouldn't be able to use all the things that run on electricity in your house. If everyone couldn't use as much electricity as they needed for their homes and businesses, they would have to make many changes in their lives. The economy wouldn't grow as fast and most people's lives woudn't be as good as they are now. Or maybe the quality of their lives would decline a lot and the GDP line would go down.

People who want to use solar electricity have to figure out how many watts of electricity their equipment uses so they know the total amount of electricity that their solar cells need to produce. If they guess that the equipment will need 500 watts to run, but all of their equipment, together, needs 1,000 watts, some of the equipment won't run.

Visit www.solarenergy.org to make your own solar electricity project on the computer. You'll pick the things you want to run, and then you'll build your system so it runs them all. You'll see which things could be made to run on fewer electrons, with fewer watts, and you'll learn why it's important for your project to run efficiently.

It's also neat to see how the amounts of resources we use to make electricity change over time. Let's compare energy resource bar graphs for 1974, 1997 and 2020 refer to graphs 5, 6 and 7). In between those years, only small changes occurred in the resources used to make electricity, so the GDP line kept going up. It would be terrible if one of the Power Pie slices suddenly vanished. But, if we lost one of those resources, there wouldn't be any other energy resource that could grow big enough and fast enough to fill the missing Power Pie slice. The GDP line would go down sharply.

The biggest change in amounts used happens with coal, which grows from about 750 billion kilowatt-hours (BKWH) in 1974 to about 2,250 BKWH in 2020. Natural gas amounts really change, too, from about 250 BKWH in 1974 to almost 1,500 BKWH in 2020. Renewable energy resources (non-fossil fuels like wind and solar) increase some, and nuclear power ends up a little higher in 2020 than in 1974.

Here's another way the data from the U.S. Department of Energy shows these changes (refer to graph 8). Each line represents a different resource used to make electricity. Remember that the lines from 1974 to 1997 show what has happened. The lines to 2020 show the DOE's best prediction for future resource use based on everything we know about now that could affect the way these resources are used.