Have you checked your light bulb supply?

If you go to a store shelf in America, you won't find 100-watt incandescent light bulbs.

And starting this week, finding a 75-watt incandescent will be increasingly difficult as well. What you will find, as far as incandescents are concerned, are some dusty 3-ways, a few sad 71-watt bulbs, and some ornamental and specialty bulbs. 

The effective ban on incandescents started with the Energy Independence and Security Act of 2007.

The Act requires that general-purpose light bulbs that produce 310 to 2600 lumens be 30 percent more energy-efficient than current incandescent bulbs in 2012 to 2014. The efficiency standards started with 100-watt bulbs in January 2012 and end with 40-watt bulbs in January 2014. Specialty bulbs are exempt. Other governments have passed laws to phase out the use of the inefficient Edison bulb as well (see EU, China, et al.).

Elected officials such as Ron Paul, Joe Barton, and Michelle Bachmann railed against the law as a threat to individual rights and a testament to crony corporatism.

But the Act is here now and those incandescents are going away. It's happening now.

The interim (?) replacement is the compact fluorescent (CFL), an efficient technology that has improved in performance and light quality. The bulbs have a consumer perception issue and performance and disposal challenges. But CFLs are cheap: a no-frills specimen costs $2.50, lasts for years, and reduces electric bills. And they're what's now on the shelves.

A market transition to LEDs (light-emitting diodes) has also begun. Groom Energy and GTM Research predict that the LED enterprise lighting market will surpass $1 billion in annual revenue by 2014. LED fixture prices have fallen 24 percent in the past two years, and the prices will continue to come down.

Most of the early growth will come in the commercial and industrial LED lighting space, where the 2010 U.S. market stood at about $330 million in annual revenue. 

LEDs remain expensive, but offer long lifetimes and energy savings. As with CFLs, there are contrasts between incandescent light quality and LED light quality.

There are immense business opportunities along the lighting value chain and there is intense competition at the chip and package level (Osram, Philips, Toshiba, Cree, Bridgelux), the bulb level (Philips, General Electric, Sylvania, Lighting Science Group, Switch, Soraa, Lednovation, Lemnis, LedWiser) and at the fixture or networked lighting layer (Daintree Networks, Redwood Systems, EnLighten, Lunera, Digital Lumens).

We've asked the question before: when will the LED bulb vanquish the incandescent?

Vastly improved technology, lower prices, consumer awareness, and energy efficiency legislation are all compelling the multibillion-dollar lighting industry to flip to fluorescents, LEDs and other lighting technologies.

LEDs can significantly reduce consumption of electricity in the U.S. and eliminate billions of bulbs from the waste stream. But so can fluorescents.

That's why the shift to LEDs is happening much more slowly than VCs or entrepreneurs expected. Widespread consumer and residential penetration of LED lighting is still some years away.

In the meantime -- you may want to stock up on 60-watt incandescents.