A few weeks back, I wrote about the rise of green tech. Many folks have been asking me how real this trend is. I’m not sure what they mean by “real” (I’m a virtual gal, myself), but here’s my best shot at an answer.

Green’s as real as it gets, baby. Sure, people can dicker over whether global warming is really occurring, and if so whether it’s due to human activities. And we can debate whether the concept of “peak oil” actually exists, and if so, whether we reached it in 2004, or we’ll reach it in 2014. But one trend that’s indisputable is that the cost of energy will continue to increase, at least for the foreseeable future.

And here’s the kicker: Pretty much any industry is essentially a machine that turns energy into useful stuff. General Motors and Toyota turn energy into cars. IBM and HP turn energy into servers. And we in IT turn energy into information.

As any good CFO will tell you, any time the cost of a significant raw material is increasing, it’s time to reassess your business practices. There are only a handful of ways to cope: You can pass along the cost to your customers, which works until they can no longer afford to buy what you’re selling. You can hold the line on costs and absorb the hit on your margins, which works until you can no longer to produce what you’re selling. Or, you can reduce your consumption of the expensive resource.

Enter green. As I noted previously, for most companies, green isn’t about saving the world — it’s about saving your company money, primarily (but not exclusively) by reducing energy costs.

How? Investing in key technologies helps. Server and desktop virtualization can maximize computer utilization, for example. Maximizing utilization matters because machines consume power even when they’re idle — so it’s better to have 20 servers at full utilization than 100 servers at 20%. And automated power management makes it easy to power unused machines down (or off).

But it’s really how you use these technologies that makes the difference. Two key points stand out from the research I’ve been doing in this area. First is that knowing what to do isn’t the same as doing it. Just 13% of IT executives at the companies I work with actually know their data center utility bills, for example. And a mere 3% are powering unused servers down. The situation’s a bit better on the desktop front — fully half the folks turn off desktops at least some of the time.