The National Academies: What You Need To Know About Energy

The National Academies

What You Need To Know About Energy

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Lighting

There are enormous opportunities for efficiency gains across a wide range of products and processes. One area regarded as particularly ripe for improvement is lighting, which accounts for 18% of all electricity use in the United States and 21% of the electricity for commercial and residential buildings. Major research efforts are in progress to reduce those costs by using the same technology that now creates the glowing lights on appliances: the light-emitting diode (LED).

LEDs generate relatively little heat, last 100 times longer than an incandescent lightbulb, and convert about 25% to 35% of electrical energy to light, as opposed to about 5% in a conventional incandescent bulb.

LEDs are “solid-state” devices made of materials similar to those in computer chips. They produce illumination by allowing electrons to flow across an electrical junction (the diode) and drop into a lower energy state, releasing the difference as light. LEDs generate relatively little heat, last 100 times longer than an incandescent lightbulb, and convert about 25% to 35% of electrical energy to light, as opposed to about 5% in a conventional incandescent bulb. Additionally, they do not require bulky sockets or fixtures and could be embedded directly into ceilings or walls.

At present, such systems are too expensive for broad commercial use. But if they can be made affordable, the effect will be dramatic. By one expert estimate, widespread use of LEDs would reduce consumption of electricity for lighting by 50%—a savings of about $10 billion a year in the United States. And it would reduce worldwide demand for electricity by 10%, an amount equivalent to about 125 large generating plants.

Compact fluorescent bulbs (CFLs), a high-efficiency lighting option that’s already available, use electricity more sparingly than traditional incandescent lightbulbs. According to the AEF committee’s findings, about an 80% increase in energy efficiency could be realized immediately if incandescent bulbs were replaced with CFLs or LEDs. That translates to about a 12% decrease in overall electricity use in buildings.

Compare the energy used by CFLs and incandescent lightbulbs in Understanding Efficiency.

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Energy Hands-on

What do you know about energy?

How much of the U.S. supply of natural gas is imported from outside North America?

  • Correct!

    Less than 2% of the U.S. supply of natural gas is imported from outside North America.

  • Sorry, that’s incorrect.

    Less than 2% of the U.S. supply of natural gas is imported from outside North America.

  • Sorry, that’s incorrect.

    Less than 2% of the U.S. supply of natural gas is imported from outside North America.

Energy Defined

Quad

A unit of measure used to describe very large quantities of energy, such as the annual energy output of the United States. One quad is equal to one quadrillion—that is, one million billion, or 1015—Btu.

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National Academies Press

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