As we start to develop content for the upcoming Sustainability issue of IT in Canada, I'm becoming much more conscious of links and stories that are connected with green IT - and there seem to be a tremendous number of new initiatives that help underscore the cost and carbon savings associated with IT.
One that crossed my desk today was a TCO calculator for monitors from ViewSonic. It calculates savings based on using specific ViewSonic products to replace existing monitors by comparing power usage.
When I used the calculator (by following
this link), I asked it to compare a 19" LED monitor with one drawing 100 watts - which, according to ViewSonic marketing VP Adam Hanin, is a rough average for CRT technology. The calculator told me that if I were to use the monitor 60 hours a week (and generally, they're left on longer than that - many people never shut off their monitors), I would save $23.95 per year by switching to LED technology. Using the figures provided in the calculator, this represents nearly 250 kW/year - and if we apply the formula for kW to carbon that Carbonfund.org uses in their calculators, we find that LED vs. CRT technology would reduce carbon emissions by 322 pounds per year.
This raises several questions, including: what's the comparison between LED and other technologies? What's the payback period on a monitor that saves $23.95 a year? And what's the overall carbon benefit of LED monitors?
Let me start with the first question. When I called Adam, he told me that a 19" LED monitor can be expected to draw 18 watts, vs. 32 watts for a 19" LCD, and 100 watts (as noted previously) for a 19" CRT. This means that LEDs are nearly 2x more efficient than LCDs, and about 6x more efficient than CRTs. I found this a little surprising - I knew CRTs were not energy-efficient, but I did not realize how much additional benefit LEDs offer vs. LCD technology.
The answer to the next question - payback period? - is, "a long time." When I checked on shopbot.ca, the median price (of five) for a ViewSonic VX1932wm was $177.25. At $23.95, this puts payback out to 7.4 years. Basically, an energy-efficient monitor makes sense if it's time for you to refresh technology, but not as a short-term source of cost savings.
Lastly - what is the overall carbon benefit of LED monitors? Figures available on the Internet vary, but the most common figure I've seen is that one mature tree will absorb roughly 50 lbs of carbon per year - meaning that a technology that reduces carbon by 300 lbs per year has about the same impact as six mature trees. Put another way, if one were to use that 19" LED for 7.4 years, until its energy benefit (vs. a CRT) fully repaid its purchase cost, the total carbon savings would be very close to one ton.
Now, as I've tried to infer with the phrasing in this post, most of these numbers are subject to a relatively high degree of variability. The most important concerns power sources: the actual carbon impact of a kilowatt hour depends on how the electricity is generated, and power generated in Canada (and especially, in places with a high proportion of hydro in the mix, like BC) has much less carbon impact than power generated in the central US states, where coal is the dominant fuel source. There are other variables in play here, as well. At some point, though, calculations like these are as important for the broad points they make, as for the specific numbers they present: overall, efficient technologies like LED monitors help reduce our IT-related power and carbon footprint, which has both bottom-line and environmental benefits.
