Ask an Expert about Energy Efficiency


Have you ever wondered whether cars could run on cow manure? Or what kind of a difference it makes to use compact fluorescent bulbs? Now you can get answers to these and all your energy-related questions. Just Ask an Expert!

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Is it true that cars could someday run on cow manure?

Answer: Yes! Manure can be made into a gas containing methane. (Methane is the same energy-rich gas found in natural gas.) Certain types of bacteria emit this gas as they consume manure collected in special air-free tanks. The mixture of gases produced in this way, called biogas, can then be used in some modified car engines instead of gasoline, or burned in a boiler to generate heat or electricity.

I have heard that landfills can be a source of energy. How does that work?

Answer: Organic waste emits methane as it decomposes—or rots—in the landfill. Landfills can collect and treat the methane and then sell it as a commercial fuel, or they can burn it to generate steam and electricity. Today, there are almost 400 gas energy landfill projects operating in the United States.

Why is it important for people in the United States to save energy? Aren’t we just a relatively small part of a large planet?

Answer: Although Americans make up only 5 percent of the world’s population, we use about 25 percent of the world’s energy! And we consume about 15 times more energy per person than does a citizen of a typical third world country.

What kind of a difference does it really make to replace a regular light bulb with an energy-saving one?

Answer: Replacing one incandescent light bulb with an energy-saving compact fluorescent bulb prevents about 1,000 pounds of carbon dioxide from being emitted to the atmosphere from power plants, and saves about $67 dollars in energy costs over the bulb’s lifetime.

What’s the difference between global warming and the greenhouse effect?

Answer: The greenhouse effect is created because certain gases sent into our atmosphere, such as carbon dioxide, allow radiation from the sun to pass through the earth’s atmosphere, but prevent a portion of the infrared radiation from the earth’s surface and lower atmosphere from escaping into outer space. This process occurs naturally; without it our planet’s temperatures would be about 60 degrees cooler! Life as we know it simply would not exist without the natural greenhouse effect. However, many scientists believe global warming is happening because the greenhouse effect has become intensified by human activities: These activities (primarily the burning of fossil fuels) add more carbon dioxide and other gases to the atmosphere and accelerate the earth’s natural warming process.