With energy prices soaring and corporate cost-cutting at full tilt, it's almost impossible to avoid the topic of energy efficiency. Just about every product is trying to convince us how green it is. That's excellent, but how many of us have actually sat down and done the math to see what our IT operations consume and what they cost us?

In my experience, very few. But try running the numbers, and you'll quickly discover that going green actually does pay.

Let's focus on that nasty little energy hog, the desktop PC. The potential energy cost savings of desktop virtualisation are quite high, yet few organisations have moved to VDI, Citrix/Terminal Services, and other forms of SBC (server-based computing) on a large scale. It's still about 100 times more likely to see a desktop on an employee's desk than it is to see a thin client.

So how much could you save? Imagine a typical enterprise with 1,000 employees running conventional desktops during business hours (10 hours a day, five days a week). Employees have their own standard desktop that they sporadically use for half the day. The other half of the workday, the box sits idle, and at night it goes into suspend mode.

Excluding the monitor and other peripherals, our example enterprise will spend roughly $41.25 per year to power and cool each desktop. Doesn't seem like a big deal, right?

Not so fast - that $41.25 suddenly looks a lot bigger when you consider the whole fleet of 1,000 desktops over the expected three-year lifetime of those desktops, adding up to more than $123,000. That could be as much as 15 percent of what it cost to actually buy the desktops in the first place. If our enterprise were a 24/7 shop that leaves its desktops on and in use constantly, that figure would balloon to nearly $400,000 over three years - approximately 45 percent of the acquisition cost of the desktops.

Now we're talking real money. Even if you don't believe in conservation or saving the planet, think of what else you could do with that money. Maybe hire another employee? Or how about some more SAN capacity?

Speaking of storage, it's worth mentioning that those 1,000 desktops - even if you get them with the smallest hard drive available (160GB) - will provide our imaginary enterprise with more than 145TB of almost completely useless and difficult-to-manage storage. In fact, if you forget the rest of the desktop and just look at the hard drive, our enterprise is spending nearly $10,000 just to power and cool hard drives. That's almost half of what it would cost to power a fleet of 1,000 thin clients.

Of course, you can't just shut off all your desktops, as tempting as that may be - you need to replace them with something. Let's say our enterprise shifts from thick desktops to thin clients. That step alone will shrink the three-year desktop power/cooling budget from about $123,000 to around $20,000. If we're connecting to a blade-based Citrix or VDI infrastructure, the server resources required to provide the compute environment those thin clients will connect to will cost around $15,000 to power and cool over three years.

In total, we will have saved a net of $88,000 - just in power costs. That's not taking into account the longer useful lifetime of the thin clients, substantially decreased management costs, or any of the other benefits of SBC.

Even if SBC isn't viable in your environment, you can at least enable the advanced power management features on the desktops you do have. Many IT departments will disable these settings to avoid complaints from users or to make it easier to use remote desktop management tools. However, these settings can have a huge impact on the power consumption of standard desktops -- often more than halving it. It's not as good as a thin client, but it's better than nothing.

If that's all so awesome, why don't more enterprise IT departments think this way? The biggest and saddest reason is that savings from desktop power consumption are very, very rarely considered a benefit to IT.

You'll often see lots of IT effort expended to make the data centre efficient, but that's because the infrastructure to support those areas (UPS, air conditioning, and so on) often comes out of IT's bottom line. Power for the wall jack next to the receptionist's desk doesn't.

As you start to put together your next budget, do the math for your organization and give this some hard thought. It's not a given that SBC will be appropriate for your users or that management will recognise and credit IT with the power savings you can provide. If you can overcome those challenges, you'll be able to spend that money on things that you actually need rather than watching it go down the drain and hurt the environment at the same time.