Getting an accurate accounting of cleantech jobs in the U.S. is nearly impossible. It’s not for a lack of trying. There have been dozens of projects at the national, state and metro level designed to track and quantify cleantech jobs, and to some extent, these attempts have done a decent job.

But for all these efforts, the reality is that the North American Industry Classification System (NAICS), the standard used by federal statistical agencies in classifying business establishments and tracking jobs, does not account very well for green industries and their myriad distinctions. The NAICS, for instance, currently lumps things like solar, wind and tidal into one “Other Electric Power Generation” category and has no categories for hybrid electric vehicles, green buildings, recycling and many other key sectors. Not exactly the best way to track the emerging industries of the future.

Past efforts to provide a more accurate accounting of clean-energy jobs include The Pew Charitable Trusts’ The Clean Energy Economy report and IHS Global Insight’s Current and Potential Green Jobs in the U.S. Economy report prepared for the U.S. Conference of Mayors. Both of these reports had very similar results, reporting a total of more than 750,000 green/clean-energy jobs in the U.S. in 2007 and 2006, respectively. But these reports, for all their positive contributions, were unable to do a completely accurate accounting because so much of the required underlying data just wasn’t available yet.

So is there anything more promising on the horizon?

Later this year, The Brookings Institution and Battelle will be releasing a new report that picks up where Pew and IHS left off. They plan to release data on “clean jobs” in more than 100 metropolitan areas, including a trend analysis for the period between 2003 and 2010. And in the spring of 2012, the U.S. Bureau of Labor Statistics (BLS) plans to release its first national survey of green jobs. Most important, the BLS is working diligently to overhaul the NAICS codes to include and cover cleantech jobs and sectors. The BLS currently defines green jobs in five distinct areas: 1) energy from renewable sources, 2) energy efficiency, 3) pollution reduction and removal, greenhouse gas reduction, and recycling and reuse, 4) natural resource conservation, and 5) environmental compliance, education and training and public awareness.

In some ways this hard-to-define, Wild West environment reminds me of the Internet back in the early 1990s. I attended a number of World Wide Web consortium meetings at a time when programmers, academics and others convened to hash out the underpinning language of the web. These agreements enabled the Internet of today, with its open protocols, shared language and agreed-upon standards.

We need similar agreements today on what constitutes a green or clean economy, and need to make sure we are creating the right NAICS codes to track the entire cleantech jobs value chain. Admittedly, the analogy with the web only goes so far, but I believe that agreed-upon, broadly-accepted accounting methods for cleantech jobs are critical in enabling the growth of the broader clean-energy economy.

One of the big areas of contention revolves around just what constitutes a clean, green job?

Do you include nuclear power and waste-to-energy, or not? How far down the value chain do you go? Do you include users of clean technologies, or just producers? What about the thousands of people working on sustainability and energy efficiency in heavy manufacturing, retail and scores of other non-cleantech industries?