A couple years ago there was a small panic wave in the IT community when a new federal law changed the dates of daylight savings time, starting it earlier in the spring and ending it later in the fall. Even Microsoft was caught flat-footed, having to release a hasty patch to permit client PCs and servers to catch up with the change. A little-noticed provision in that same law also took aim at the humble incandescent light bulb, essentially outlawing it in the coming few years.

Incandescent bulbs currently enjoy 80% market share in the U.S. market, but are incredibly inefficient, generating 90% heat and only 10% light. Under the 2007 energy bill, by January 2012 100 watt incandescent bulbs will be outlawed, and by January 2014, 40 watt light bulbs will be history too. If you have a light fixture that only works with incandescent bulbs (in terms of size and shape, for example), now may be the time to start stocking up!

Replacing incandescent bulbs are halogen, compact fluorescent (CFL), and LED bulbs. Each of these technologies have their drawbacks. Halogens, for example, require special handling and are nearly as inefficient as incandescent. CFLs don't play nicely with dimmers and can cast very harsh lights, especially undesirable in residential applications. And LED bulbs are just very costly and have several design challenges. Each of these technologies are also more expensive than traditional incandescent bulbs, a real consideration in a severe recession.

A recent article in the WSJ explores these alternatives. The really interesting technology is LED, traditionally used in consumer toys and commercial applications such as traffic lights. From the article:

Wal-Mart Stores has started selling a consumer LED bulb that uses just seven watts of electricity and claims to last for more than 13 years. It costs around $35 -- a daunting price tag for a light bulb. "We're kind of testing the waters," says Rand Waddoups, Wal-Mart's senior director of strategy and sustainability. "This is a behavior change, and that requires some work."

I recently bought one of these Wal-Mart LEDs (made by GE), and I love it. I leave it on all day and all night in an outside light fixture to light up the patio for security, and given that it costs literally pennies in electricity costs, I don't feel bad about leaving it on. Sure, it's pricey for now, but as incandescents begin to phase out, I suspect we'll see a battle royale between CFL and LED technology. Technologically speaking, LED appears to be the winner. Hopefully we'll start to see bulbs such as these in the U.S. soon. What type of bulbs will your data center use in the future?