Measuring your green IT baseline

Forrester offers some simple equations to calculate how much you spend annually to power your IT gear and how much CO2 it produces

What you can't measure, you can't control. That adage may not be universally true (I can measure my two-year-old godson but can't control him), but it's certainly apt when you're talking about bringing greater energy efficiency and eco-friendliness to your IT operations. In a nutshell, if you don't know how much power your IT gear consumes nor how much CO2 it produces, you're going to have difficulty coming up with a strategic plan to reduce either.

That's one of the points emphasized in a recently released report from Forrester titled "Is Green IT Your Emperor With No Clothes?" In it, author Doug Washburn and his associates urge organizations to measure "their green IT baseline — an annual estimate of the energy consumption, carbon dioxide (CO2) emissions, and financial costs of operating IT."

[ For more tips from Forrester on developing a smart sustainable-technology action plan, please read "Strategic steps down the green IT path." ]

In the report, Forrester provides some relatively simple equations to help organizations figure out how much electricity they're using per year to run their various IT systems, as well as how much it costs and how much CO2 it creates. (I easily built a spreadsheet containing the various equations, and I'm certainly not an Excel wiz.)

First, Forrester says that you need count up all your IT equipment, outside the datacenter — including PCs and laptops, peripherals, and telephony gear — as well as inside, which would encompass servers, storage and networking gear, CRAC equipment, PDUs, and lighting. Doing an inventory of all your IT assets in this way is a good practice in general; it can help you find machines that are plugged in but doing little to no actual work. (McKinsey and Company reported earlier this year that on average, distributed systems in datacenters run at only 5 to 30 percent capacity.)

Once you know how many computers, servers, switches, and so forth you have, the Forrester report says that you should figure out the energy draw in kilowatts for each type of equipment. That might seem like a difficult task. How do you measure it? Well, you could ask the manufacturer and hope they give you a figure that accurately reflects your usage of said asset. Alternatively, you could measure it for yourself.

One of the more popular tools I've seen for that task is Kill-a-Watt from P3. You plug your device into Kill-a-Watt, which in turn will tell you how much power the piece of equipment is consuming at any given moment. (InfoWorld Test Center Analysts swear by Kill-a-Watt for testing anything from workstations to storage gear.)

So, for, example, the average PC draws between 60 and 250 watts, according to "Mr. Electricity" Michael Bluejay. Turn that number into kilowatts by dividing by 1,000. Thus, a system that draws 250 watts is using 0.25 kilowatt.

Finally, you need to figure out how many hours per year your assets are running. So, for example, you're ideally using PC power management software to ensure that the computers at your office don't run outside of business hours; otherwise, you're wasting money keeping machines and monitors powered on for no reason.

[ For more about saving money through PC power management, please read "When PCs don't snooze, you lose." ]

After you've gathered those three figures, you plug them in to this equation to calculate how much energy each asset category uses per year: (Number of assets) x (Energy draw, in kW, per asset) x (Annual uptime per asset, in hours) = Annual energy draw in kWh

Thus, if your organization has 1,000 PCs that each draw an average of 150 watts of power along with 1,000 17-inch LCD monitors that each burn an average of 35 watts, and you keep those systems running 2,340 per year (45 hours per week time 52), your annual energy draw in kilowatt hours would be 432,900. I arrived at the figure this way: (1,000 PCs x .15kW x 2,340 hours per year) + (1,000 monitors x .035kW x 2,340 hours per year) = 351,000kWh per year for PCs + 81,900kWh per year for monitors = 432,900 kWh total per year

After you have that figure, it's relatively easy to calculate how much money you're spending to power your IT assets each year as well as the pounds of CO2 emissions associated with them. To figure out the costs, multiply your annual energy draw by how much you're paying your utility per kWh. According to Forrester, the average is $0.0946. To figure out the carbon emissions, multiply the annual energy draw figure by 1.34, "the U.S. national average of CO2 emissions per kWh." (The number is lower in areas that use cleaner sources of energy such as natural gas compared to those that use sources such as coal.)

Expressed as equations: (Annual energy draw in kWh) x (Cost per kWh) = Annual energy costs (Annual energy draw in kWh) x 1.34 = Pounds of CO2 emitted annually

Drawing on our previous example, then, say the company with the 1,000 PCs and 1,000 monitors is paying the average amount per kWh. It could figure out its annual costs thusly: (351,000kWh per year for PCs + 81,900kWh per year for monitors) x $0.0946 per kWh = $40,952.34 total per year.

To figure out associated carbon emissions, it would use the following formula: (351,000kWh per year for PCs + 81,900kWh per year for monitors) x 1.34 lbs of CO2 = 580,086 lbs. of CO2 per year.

[ Should you care about your carbon footprint? For one argument in favor of reducing your CO2 count, read "CO2 spewer? See you in court!" ]

With some time and effort, you can figure out your rough green IT baseline and have a sense of what you're spending to power your IT gear and supporting equipment (CRAC units and PDUs, for example). But of what use are those numbers really?

For starters, you can use them to find ways to reduce costs. Earlier, I mentioned PC power management. You could calculate a what-if scenario to see how much you'd save on powering down computers and monitors versus how much it would cost to license the necessary software. Moreover, after six months or a year, you could look back and compare your costs to see how much of a difference it made.

Additionally, as recommended by Forrester, if you do manage to gather all those calculations, you'll have the figures necessary to estimate your PUE (Power Usage Effectiveness) and DCIE (Datacenter Infrastructure Efficiency) numbers. Those are figures promoted by The Green Grid to help datacenter operators gauge how efficiently their facilities are using power. Calculating PUE entails dividing the total amount of power a facility uses (for IT equipment as well as PDUs, lighting, and CRAC) by the IT equipment power; that is, the power consumed by IT gear. (A lower number means a more efficient datacenter.) DCIE is the reciprocal of PUE.

As a final example, if your organization has made a pledge to reduce its carbon footprint, using the calculations recommended by Forrester can help you set your starting point.

I've just scratched the surface of Forrester's "Is Green IT Your Emperor With No Clothes?" report. It also explains why IT can't technically ever be green, as well some tips as to how to create a green IT strategy. The report is available via the Forrester Web site for $279.

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