Cleantech Group has just released its ranking of the top 100 cleantech firms for 2010. Among them are smart grid networking sweethearts Grid Net, Silver Spring Networks and eMeter, smart meter maker Landis+Gyr, LED pioneers Lemnis Lighting and Bridgelux and EV charging upstart Better Place.

Though most of the firms on the list share only the most tangential relationship with green computing, data center operators might want to take notice of two companies that can help lower IT energy costs. The first is Ice Energy, makers of the Ice Bear system, whose technology freezes water during off-peak nighttime hours to deliver cool air during the hot, sunlit day. The kicker is that the technology works with the vast majority of commercial HVAC units, so it’s less of an costly overhaul of a data center’s cooling system and more of an energy and cost savings add-on, particularly in toasty regions with few free-cooling options.

Next is Bloom Energy, the fuel cell startup that arrived with a bang earlier this year. Though I’m still not convinced that it will become the primary power plant for a data center any time soon (sub req’d), it’s a solid backup energy and carbon emissions reduction solution for well-heeled corporations.

But as Richard T. Stuebi points out in his blog post, the list doesn’t necessarily mean that all the companies therein are guaranteed successes. He singles out Imara, the solar firm that made the cut in 2009 only to flame out in the same year. Nonetheless, making the Cleantech 100 is a feather in any green startup’s hat. Plus, there’s some tantalizing data to be gleaned from the list.

According to Stuebi, the U.S. still holds the cleantech lead, but China is picking up steam. Also, energy efficiency firms edged out solar companies for the first time, and two VC’s, Vantage Point and Kliener Perkins, (unsurprisingly) dominate the list in funded startups.

View the full list here.