I had the opportunity to meet Roger Tipley at the recent Power Electronics Technology
Exhibition & Conference in Dallas. Roger is a senior technologist and engineering
strategist at Hewlett-Packard as well as a board member of an organization called
The Green Grid (www.thegreengrid.org).
The Green Grid has been operating since January
and has already grown to 102 members. It
is a consortium of information technology companies
and professionals whose goal is to
improve energy efficiency in data centers
around the world. Tipley’s keynote address was
entitled “Opportunities for Energy Efficiency
Innovation in the Power Electronics Industry.” He
began by pointing out that he would be talking
“completely end to end” as far as opportunities
in the entire supply chain of energy, from the
source of electricity to the ultimate consumer of it.
Measurement is key
Before delving into opportunities,
Tipley pointed out the need for measurements of energy efficiency.
The Green Grid has proposed power usage effectiveness
(PUE) and its reciprocal, data-center infrastructure efficiency
(DCiE). These metrics enable data-center operators to quickly
estimate the energy efficiency of their data centers and compare
the results against other data centers. This helps them determine
the energy efficiency improvements that need to be made.
For a better idea of what these measurements represent,
think of power consumption in the data center as having two
components. One is the total facility power. This includes everything
that supports the IT equipment load: power delivery components
like the UPS, switch gear, generators, PDUs, batteries,
and distribution losses external to the IT equipment; cooling system
components like chillers, computer room air conditioning
units (CRACs), direct expansion air handler (DX) units, pumps,
and cooling towers; compute, network, and storage nodes; and
other component loads such as data-center lighting.
The other component of the equation is IT equipment power.
This includes the load associated with all of the IT equipment,
such as compute, storage, and network equipment, along with
supplemental equipment such as KVM switches, monitors, and
workstations and laptops used to monitor or otherwise control
the data center.
The PUE measurement is simply the total facility power divided
by IT equipment power, while DCiE is the reciprocal of PUE.
While both of these metrics are essentially the same, the group
points out that they can be used to illustrate the energy allocation
in the data center differently.
In support of these measurements, the
group announced last month the grand opening
of the Schneider Electric Technology Center.
This state-of-the-art testing facility in O’Fallon,
Mo., will be made available to The Green
Grid to further enable progress on the part of
the group’s Technical Committee. This 97,000-
square-foot facility includes research and
development labs along with dynamic test facilities.
American Power Conversion (APC), a business
unit of Schneider Electric, is one of the
founding members of The Green Grid.
Where's the opportunity?
From end to end, Tipley
explained where he sees opportunity knocking for power systems
designers. For example, he pointed out that converting
coal to electricity with today’s technology yields only about 35%
of the actual energy available in that source. Not very good.
Transmission losses aren’t bad, only about 2%, which leaves
33% for a facility like a data center.
Other energy sources, such as wind, are potentially up in the
60% yield range. So there are opportunities for designers working
with wind turbines to deliver energy much more efficiently
than is now possible with a source such as coal.
But The Green Grid doesn’t really focus on the inefficiencies
in the power plant, which are significant, or with the smaller losses
that occur in the transmission of energy to the facility.
Instead, The Green Grid is focused on power in the data center
itself and using that power more efficiently. The opportunity here
lies in more efficient designs for both the facility and the IT
equipment. Tipley said that a poorly designed data center might
use two-thirds of the available power on cooling equipment.
Another part of Tipley’s talk covered the various power-distribution
configurations being used in data centers today. Of
course, each of these configurations has advantages and disadvantages.
On its Web site, the group has published a white
paper entitled “Qualitative Analysis of Power Distribution Configurations
for Data Centers” that provides a good overview of seven
different configurations and their pros and cons.
For more information on The Green Grid, visit the group’s Web
site. To view a video of the keynote, point your browser to electronicdesign.com/shows/power2007/index.cfm.