In 2011, AT&T used 344 kWh of energy for every terabyte of data transferred on its network, down from 415 kWh per terabyte in 2010 and 654 in 2008. Since 2008, AT&T has recorded annual reductions in this metric of at least 17 percent every year. From 2008 to 2009 the energy intensity of AT&T’s data dropped 24 percent.
Last year the company instituted around 4,500 energy-saving projects including motion sensor replacements in central office space and airflow remediation in data centers. As a result of these upgrades the company saved around $42 million in 2011, the report says. In 2010, the company announced that it found $44 million in annualized energy savings by implementing 4,200 energy efficiency projects.
The company aims to reduce its electricity consumption relative to data growth by 60 percent by 2014.
As well as reducing its energy intensity the company has increased its renewable energy use by over 11 percent, from 2,849,896 kWh in 2010 to 3,182,923 kWh in 2011. Most of this energy is from traditional solar power systems, but 2011 saw the introduction of a 3,888 kW solar plus fuel cell offering.
The company’s absolute domestic carbon footprint has increased. From 2010 to 2011 AT&T’s total domestic CO2 emissions jumped almost 2 percent from 8,925,724 to 9,066,558 tons of metric tons of CO2 equivalent. The 2011 figure is now just shy of 2008 levels. The company’s combined global emissions also rose around 2 percent year-on-year (see graph, below).
Some 88 percent of AT&T’s emissions come from indirect, or scope 2, sources such as purchased electricity and steam. Due to increased demand on the network, the company saw a more than 3 percent increase in these emissions over 2010, the report says.
The company’s water use remained static from 2010 to 2011 at 3.4 billion gallons a year. AT&T only started measuring its water consumption in 2010, with the creation of a “water scorecard.” Last year the firm began developing tools to help its facility managers increase water efficiency related to use of mechanical cooling. AT&T is also evaluating cooling tower water efficiency technology at several sites.