The technology in traditional "incandescent" bulbs is more than a century old. Such bulbs waste most of the electricity that feeds them, turning it into heat. The 100-watt bulb, in particular, produces so much heat that it's used in Hasbro's Easy-Bake Oven.

To encourage energy efficiency, Congress passed a law in 2007 mandating that bulbs producing 100 watts worth of light meet certain efficiency goals, starting in 2012. Conventional light bulbs don't meet those goals, so the law will prohibit making or importing them.

The new bulbs will also be expensive — about $50 each — so the development may not prevent consumers from hoarding traditional bulbs.

The same rule will start apply to remaining bulbs 40 watts and above in 2014.

Since January, California has already banned stores from restocking 100-watt incandescent bulbs.

Creating good alternatives to the light bulb has been more difficult than expected, especially for the very bright 100-watt bulbs. Part of the problem is that these new bulbs have to fit into lamps and ceiling fixtures designed for older technology.

LEDs are efficient, durable and produced in great quantities, but they're still expensive. An LED bulb can contain a dozen light-emitting diodes, or tiny semiconductor chips, which cost about $1 each.

The big problem with LEDs is that although they don't produce as much heat as incandescent bulbs, the heat they do create shortens the lifespan and reduces the efficiency of the chips. Cramming a dozen chips together in a tight bulb-shaped package that fits in today's lamps and sockets makes the heat problem worse. The brighter the bulb, the bigger the problem is.

The most powerful pear-shaped LED bulbs in stores today — the kind that fits existing lamps — produce light equivalent to a 60-watt bulb, though there are more powerful ones for directional or flood lighting.

Osram Sylvania, a unit of Germany's Siemens AG, said it has overcome the heat problem and will be showing a pear-shaped 100-watt-equivalent LED bulb this week. It doesn't have a firm launch date, but it usually shows products about a year before they hit store shelves.

Before the 100-watters, there will be 75-watters on the shelves this year. Osram Sylvania will be selling them at Lowe's starting in July. Royal Philips Electronics NV, the world's biggest lighting maker, will have them in stores late this year for $40 to $45.

To stimulate LED development, the federal government has instituted a $10 million "L Prize" for an energy-efficient replacement for the 60-watt bulb.

Philips has been selling a 60-watt-equivalent bulb at Home Depot since December that's quite similar to the one submitted to the contest. But it's slightly dimmer, consumes 2 watts too much power and costs $40, whereas the L Prize target is $22. Sylvania sells a similar LED bulb at Lowe's, also for $40.

However, LED prices are coming down quickly. The DoE expects a 60-watt equivalent LED bulb to cost $10 by 2015, putting them within striking range of the price of a compact fluorescent bulb.

Bob Karlicek, the director of the Smart Lighting Research Center at Rensselaer Polytechnic Institute in Troy, N.Y., thinks that price is achievable.

But, he said, "it's not necessarily clear to people in the lighting industry that LED chips were ever meant to go into a bulb."

(Source)