Monday, 06 September 2010 08:13

Power Usage Effectiveness (PUE) is a common metric for determining and publishing the energy efficiency of a data center. Like most such metrics, however, companies that are unscrupulous or that are not careful in how they measure PUE can produce misleading results. For instance, if PUE is simply defined as the total amount of electrical energy divided by the amount of electrical energy used by the IT equipment, then facilities that rely heavily on, for instance, geothermal energy might be able to publish low PUE numbers that do not truly represent that facility’s efficiency. A slightly better definition, therefore, might involve energy totals (regardless of the energy source) instead of just electrical energy. A recent white paper, entitled “Recommendations for Measuring and Reporting Overall Data Center Efficiency” (available at the Green Grid web site), summarizes the work of groups such as the Green Grid, Uptime Institute, EPA’s Energy Star program, and others in seeking to help ensure clearer and more consistent application of energy-efficiency metrics such as PUE.

Monday, 06 September 2010 08:13

The EPA recently announced that data centers will be able to begin tracking their energy efficiency using the EPA’s Portfolio Manager energy management tool in June of 2010. In addition, data centers can also begin applying for Energy Star status—a potential medal on the chests of those companies looking to draw attention to their “green” efforts.

The Portfolio Manager tool, according to the EPA’s Energy Star website is designed to allow companies to track and compare the energy and water usage of their buildings and properties. The tool allows companies to rate their energy and water efficiency, track improvements in these areas, and seek recognition through Energy Star awards. The Portfolio Manager currently provides Energy Star ratings for a range of commercial buildings including banks, hospitals, hotels, offices, retail stores, and warehouses (to name a few). On June 7, 2010, the EPA plans to add data centers to this list.

Monday, 06 September 2010 08:13

As economic factors put pressure on companies to reduce costs and as the public and government regulators demand more environmentally friendly practices, data center operators have an increasing incentive to find ways to run their facilities in a more efficient manner. To this end, some are arguing that moving from the traditional alternating-current (AC) approach to powering the data center to a direct-current (DC) model can yield tremendous benefits, both in reduced heat (and thus reduced cooling needs) and, concomitantly, reduced power usage.

As with most new concepts that challenge the status quo (and that are largely untested or that have limited deployment), the idea of using high-voltage DC to power the data center is rejected out of hand by some. A number of proponents of AC power argue that any benefits claimed by those promoting a switch to high-voltage DC can actually be achieved using more-efficient AC techniques.

Monday, 06 September 2010 08:13

The mighty Amazon ceased to flow for a while last week when it lost steam. And no, we are not talking about the river but one of the data centers of the Amazon Web Services on the East Coast.

A recent published article required corrections and the following is an update from Amazon. The outage in the data center was caused by power problems in a data center in Northern Virginia. According to a statement by Amazon here are the facts: