DIGITAL REALTY TRUST PUBLISHES INDUSTRY'S FIRST DATA ON DATACENTER ENERGY EFFICIENCY
Company Adopts PUE Metric as Standard for Measuring Datacenter Efficiency

Digital Realty Trust, Inc. (NYSE: DLR), a leading owner and manager of corporate and Internet gateway datacenters, has announced that it has published the industry's first energy efficiency data about its datacenter facilities. Digital Realty Trust will use the Power Usage Effectiveness (PUE) metric as the methodology for measuring and reporting energy efficiency in its portfolio of facilities in North America and Europe. Digital Realty Trust is the first company to provide customers with detailed and actionable information about how datacenter operations are meeting their corporate green IT objectives. The Company will also publish benchmarks that will support industry-wide initiatives to make datacenters greener and reduce expenditures on energy.

PUE is an emerging standard promoted by The Green Grid and others in the datacenter industry to provide a simple and consistent method of measuring the ratio of power delivered to IT equipment to the total amount of power used by the datacenter facility. PUE provides reliable information about the energy efficiency of datacenter facilities by calculating how much power is devoted to driving the actual computing/IT components (servers, for example) versus the ancillary support elements such as cooling and lighting.

"Significant gains in energy efficiency can be achieved by designing, building and operating datacenters in ways that reduce the overall power needs of the datacenter. This translates into minimizing the amount of power required by non-IT equipment and maximizing the ratio of power used by computing systems like servers," said Jim Smith, Vice President of Engineering at Digital Realty Trust. "Digital Realty Trust has been a leading voice on this issue since well before it gained the prominence it has today, and has achieved a number of important industry milestones related to green datacenters. However, I believe that reporting the PUE metric for our datacenter facilities is the most significant milestone yet because it will provide a model and benchmarks that can be used industry-wide to achieve dramatic increases in energy efficiency and can be used by customers to compare the energy efficiency of different datacenter facilities."

Gartner Research estimates that while energy costs have traditionally accounted for approximately 10 percent of IT budgets, this percentage could soon rise to more than 50 percent of departmental expenses due to a combination of factors including:

- Increases in energy costs,
- Increasing demand for computing capability, and
- Continued adoption of high-density computing strategies.

Datacenter energy usage accounts for a rising percentage of the total energy usage in the United States. The EPA estimates that datacenter energy usage has already grown to comprise 2 percent of the United States' annual electricity consumption, with additional growth expected.

"PUE is a compelling way to measure energy efficiency in datacenter facilities because it offers our industry an apples-to-apples comparison similar to the miles-per-gallon (MPG) fuel efficiency rating that the auto industry uses. Regardless of whether you are driving a pickup truck or a sports car, miles per gallon is a clear standard for measuring efficiency across all makes and models – and PUE provides that same kind of standard to evaluating efficiency in the datacenter world," added Jim Smith. "It will not only provide datacenter operators with important benchmarks for measuring and improving datacenter efficiency, it will also provide customers with valuable information about how their datacenter facility and their datacenter partners are supporting their green IT strategy."

Digital Realty Trust is initiating this process by reporting PUE data about the following facilities on spec sheets available through the company's Web site. Digital Realty Trust plans to broaden the program to include all of the future facilities it develops worldwide:

- The entire facility at 3011 Lafayette Street in Santa Clara, California
- Suite 230 at 3 Corporate Place in Piscataway, New Jersey
- Suite 106 at 200 Paul Avenue in San Francisco, California
- Suite 160 at 200 Paul Avenue in San Francisco, California
- Suite 102 at 1100 Space Park Drive in Santa Clara, California

"We recently commissioned a research study to assess green datacenter trends. One key finding is that companies are seeking more information about how to achieve their green IT goals and are looking for guidance from the datacenter industry about standards for doing so. Digital Realty Trust has taken a leadership position in adopting PUE as a standard approach to assessing energy efficiency, and have made a corporate commitment to share our expertise and our data," said Chris Crosby, Senior Vice President at Digital Realty Trust. "No other datacenter facility company is supporting customers in this way, and we are proud to be at the forefront of the energy efficiency movement."

Smith added, "This is just the first phase in providing valuable energy performance data to our customers. By the fourth quarter of 2008, we expect to deliver password protected portal access which will enable a customer to see real-time graphical representations of their energy utilization. Through the publication of PUE performance and the delivery of this real time data, Digital Realty Trust will be placing critical information into our customers hands, allowing them to monitor their energy usage more efficiently and make fact-based decisions to help them reduce their on-going energy costs."

To learn more about how Digital Realty Trust is using the PUE metric and to read about a number of best practices for green datacenters, view the recent Webinar entitled, "Planning and Building an Energy Efficient Datacenter" and related white papers at www.digitalrealtytrust.com/knowledge_library_LP.asp.