tion and agree with the top-level all of this electricity consumption to tous Computing ”)had a more mod- Savings available from increased use of power management tools and night shut off.

Articles in the March issue raised quite a few letters. The lead researcher of a study wrote to clarify citations of their work in a story about energy use by deskop devices. The researcher cautions about the difficulty of estimating energy use by these devices while agreeing that the problem needs to be addressed.

Oversimplified

Dear Editor:

I am the lead author of the ADL study referenced in Michael Thelander’s article, "Desktop Energy Uses Add to Energy Bills" (March). I am glad that EUN has published an article about ICT energy consumption and agree with the top-level point of the article: underutilization of power-management capabilities cause ICT devices, most notably desktop PCs, to waste an appreciable quantity of energy.

I did notice a few incorrect characterizations of our 2002 study. First, the statement that "ICT equipment was responsible for only 3% of national energy consumption" is incorrect. Our (ADL) study estimated that nonresidential ICT equipment accounted for just under 3% of national electricity consumption, which equals just over 1% of national energy consumption. This is an important distinction.

Second, our study found that all ICT equipment accounts for about 9% of commercial building energy consumption; the article attributes all of this electricity consumption to PCs only.

Third, the article indicates that "PCs and monitors at work in non-residential spaces consume 41.8 TWh of energy a year in this sector," according to ADL and LBNL research.

This data point appears to be based on our (ADL) study and not the LBNL study, so it is not consistent with figure 1 or figure 2 (which both come from LBNL, not ADL). Also, it includes displays and workstations, i.e., strictly speaking, we estimated that monitors and PCs consumed ~36 TWh in 2000.

Last, our scenario-based forecasts for ICT electricity consumption in 2005 and 2010 are only for key equipment types (PCs, monitors and displays, servers, imaging equipment, telecom and computer network equipment, UPSs), which accounted for ~90% of the annual electricity consumption (AEC) total in 2000. All projections need to include an additional ~10-15 TWh for other ICT equipment to make a meaningful comparison to the 97 TWh value for 2000. In addition, only one of our scenarios projected 135 TWh for key equipment in 2010: another scenario ("Ubiquitous Computing") had a more modest increase (to 110 TWh for key equipment).

The full study, "Energy Consumption by Office and Telecommunications Equipment in Commercial Buildings Volume 1: Energy Consumption Baseline," can be found on-line at: http://www.eere. energy.gov/buildings/documents/pdfs/office_telecom-vol1_final.pdf

Kurt W. Roth, Ph.D.

TIAX LLC

Cambridge, MA

Entertaining

Dear Editor:

I found your editorial interesting and entertaining (A Kilowatt in Every Pot, March). It seems to me that energy just isn’t an important thing for us Americans. We can drive for hours and not see anyone. Obviously, that must mean that our resources have no limit. Why, there’s still so much land to use up, fill up, and dig up.

My husband and I just got back from visiting my relatives who live in the Alps. Life is quite different there, where three families share one home (three separate entrances—but my grandparents’ house nonetheless).

There are only two cars for those three families, but that’s not a problem. If someone needs to get somewhere, they walk or take the bus. Or bum a ride off of a neighbor.

Forget trying any of those methods here in San Diego where "public transportation" (among other things) is taboo.

Elisabeth Reisch,

Electra Public Relations

San Diego, CA