Watt do you Know? Take our Energy Quiz!

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Learning a few of the basics about electric power can help you make smart energy choices.

To understand the power of conserving energy and using renewable energy instead of fossil fuels, it helps to know some of the basics about electricity. So do you know your kilowatts from your kilowatt hours? Your wind turbines from your hydroelectric power? Your megawatts from your terawatts?

Take this short quiz and find out if you know what’s watt about electricity. The answer is directly below the question, so just scroll down to see it. Keep track of how many questions you get right, and give yourself one point for each correct answer. Then check out how you score at the end.

1. Your electric utility charges you based on how many of these you consume:

A. Volts
B. Watts
C. Amps
D. Kilowatt hours


Answer: D. Kilowatt hours. 

A kilowatt is equal to 1,000 watts, and a kilowatt hour is equivalent to one kilowatt of power used for one hour. This helpful page can help you figure out how the energy each of your appliances uses translates into the kilowatt hours on your bill.

2. In the United States, most electricity comes from:

A. Coal
B. Oil
C. Natural Gas
D. Nuclear

Answer: A. Coal.

Nearly half the electricity in the United States comes from burning coal, which causes a number of environmental problems.

Natural gas and nuclear are next, and they each account for about 20 percent of our electricity. On the other hand, just a small fraction—about one percent—of our electricity comes from oil. However, all of these fuels pose environmental and health issues. Here are more about problems with fossil fuels and issues with nuclear safety.

3. In the United States, the renewable energy we use mostly comes from:

A. Solar
B. Wind
C. Hydropower
D. Geothermal

Answer: C. Hydropower.

According to the U.S. Energy Information Agency (EIA), the largest share of the renewable-generated electricity comes from hydroelectric energy (75 percent), followed by biomass (14 percent), wind (7 percent), geothermal (4 percent), and solar (0.1 percent) .   (Note that these numbers are for electricity, not for other energy uses, such as transportation and home heating.)

Chances are, you’re hearing a lot more about wind power, because it’s growing so rapidly, as is solar. But right now in the United States, these still produce a very small share of our electricity, and both are well behind hydropower.

4. So how much electricity do you use? The average American household uses this many kilowatt hours (kWh) at home each year:

A. 100 kWh
B. 1,000 kWh
C. 10,000 kWh
D. 100,000 kWh

Answer: C. About 10,000 kWh per year. 

Here’s a chart from the EIA that shows exactly how that breaks down. Each kWh shows up as only a few cents on your electric bill (the national average is 10 cents) but the pollution adds up fast. Electricity is the largest source of U.S. carbon dioxide emissions, closely followed by transportation.

So how much carbon is that? You can figure that every kWh on your bill amounts to between 1 and 2 pounds of carbon dioxide. (Each kWh generated produces an average of 1.3 pounds of carbon dioxide, but it depends on the energy source. Coal produces closer to 2 pounds.)     


5. Which of these is the right size for a home-scale wind turbine or solar system?

A. 1 watt
B. 1 kilowatt
C. 1 megawatt
D. 1 terawatt

Answer: B, 1 kilowatt. 

Most home systems range from 1 kilowatt to about 5 kilowatts. (A megawatt is much bigger than that, it’s equal to 1,000 kilowatts. A terawatt is even bigger, equal to one billion kilowatts. Check out this handy chart that shows how all these units of measurement are related.)

6. Which of these is equal to 1 megawatt?

A. One backyard wind turbine
B. All the commercial wind projects in New Hampshire
C. All the commercial wind projects in Texas
D. All the commercial wind projects in the world

Answer: B. All the commerical wind projects in New Hampshire. 

At the home scale, wind power is usually measured in kilowatts, and at the utility scale, it’s measured in megawatts. Most U.S. states have one or more utility-scale wind farms, so when you talk about wind power at the state level, you’re usually talking about megawatts.

Utah, New Hampshire and Rhode Island each have about 1 megawatt of installed wind power.  Texas has the most of any U.S. state, with about 5,000 megawatts of installed wind capacity.

7. Say you have a 100-watt incandescent light bulb in your living room. How much energy would that light bulb consume if you left it on for 10 hours?

A. 100 watts
B. 10 kilowatts
C. 1,000 watt hours
D. 1,000 kilowatt hours

Answer: C. 1,000 watt hours.

That’s equal to 1 kilowatt. (And if you’re keeping track, that’s also 1.3 pounds of carbon dioxide emissions, and 10 cents on your utility bill, at least according to the U.S. average.)

8. If you replaced that 100 watt incandescent bulb with an equally bright compact-fluorescent, you would probably use a 23-watt CFL. How much energy would the CFL use if you left it on 10 hours?

A. 230 watts
B. 2,300 kilowatts
C. 230 watt hours
D. 230,000 watt hours

Answer: C. It would use 230 watt hours

That’s 770 watt hours less than the incandescent would have used. Those numbers really add up over time. (And award yourself one bonus point if you wondered if there was actually a good reason for that light bulb to be on for 10 hours.)

9. Which of these pratices actually wastes more electricity than it saves? 

A. Turning off light bulbs every time you leave the room.
B. Turning off ceiling fans when you’re not in a room.
C. Turning off the air conditioning when you’re not home.
D. None of the above.

Answer: D. None of the above!

Despite what you may have heard, all of these practices are actually good ways to save energy.   

  • Turning off the light when you leave the room saves energy, no matter how long you’re out of the room. There’s a small surge of electricity when you turn the light on, but it’s minimal, not enough to make it worth leaving the light on for any length of time. (However, some people do suggest minimizing how often you turn a compact-fluorescent on and off because it can shorten the life of the bulb. See link above for more info.)
  • Ceiling fans use a lot less electricity than air conditioning, so if you can get away with just a fan, you’re saving energy. However, the fans don’t actually reduce the temperature in a room, they just make you feel cooler. So if you’re out of the room, you save energy by turning off the fan.
  • Your air conditioner uses a lot of electricity when it’s running, but it doesn’t take long to cool down your house. Turning the thermostat up in the summer does save energy, even though your air conditioner does have to cool down your house again when you get home.


10. The benefits of using less electricity are:

A. Lower electric bills
B. Makes it easier to transition to renewable energy.
C. Reduces your carbon footprint.
D. All of the above

Answer: D. All of the above!


There are lots of painless ways to use less electricity at home, such as changing your incandescent light bulbs to compact fluorescents, zapping phantom loads and many others.

Taking these steps will reduce your electric bill and your contribution to global warming immediately. It’s also one of the first steps many experts recommend you take if you’re interested in purchasing a home solar or wind system down the road. The reason is that it’s usually much less expensive to make these energy saving changes and purchase a smaller renewable energy system, than to get the largest system necessary to meet all your needs before you’ve tried to reduce your electricity use.

So how did you score?

9 to 11 points: Shockingly accurate! Your knowledge of electricity could be measured in megawatts.

7 to 8 points: Super-powered! You’re quite the electricity whiz. No one is going to catch you
sticking your finger in a light socket.

4 to 6 points: On-again, off-again, just like a light switch. Not bad, but learn a little more and you can increase your energy-saving skills and knowledge.

0 to 3 points: Watts up? Try again!

Megan E. Phelps is a freelance writer based in Kansas. She enjoys reading and writing about all things related to sustainable living including homesteading skills, green building and renewable energy. You can find her on .