[Offtopic] sustainable IT
stephen at melbpc.org.au
stephen at melbpc.org.au
Sun Feb 25 03:55:27 EST 2007
At 01:37 AM 25/02/2007, Roland writes:
> Golly Stephen, also seems to be getting a lot thinner. I wish more
> of our schools were sustainable and don't understand why we are
> not taking more steps in that direction.
Yes :-) Eg, perhaps schools might like to support Google's proposal:
** High-efficiency power supplies for home computers and servers **
By: Urs Hoelzle and Bill Weihl for Google Inc., September 2006:
Most likely, the computer youre using wastes 30-40% of the electrical
consumes because it is using an inefficient power supply. Its difficult
to believe that
something as basic as a power supply could be responsible for that amount
but its true. The problem with power supplies is that they generate
heat, which saps
away energy meant to power the computer. That happens when the power
converts AC current into the DC current needed by computers.
At Google, we run many computers in our data centers to serve your
energy conservation and efficiency are important to us. For several years
been developing more efficient power supplies to eliminate waste from
supplies. Instead of the typical efficiencies of 60-70%, our servers
now run at 90% efficiency or better, cutting down the energy losses by a
We believe this energy-saving power supply technology can be applied to
computers, too. So weve been working with Intel and other partners to
new power supply standard. The opportunity for savings is immense we
that if deployed in 100 million PCs running for an average of eight hours
per day, this
new standard would save 40 billion kilowatt-hours over three years, or
more than $5
billion at Californias energy rates.
The technical changes we propose are very small and low-risk. For
reasons dating back to the original IBM PC in 1981, standard PC power
provide multiple output voltages, most of which are no longer used
directly in todays
PCs. Back in 1981 the chips actually did need all these voltages. But
are long gone.
Why then do power supplies continue to be built to produce multiple
answer is simple: because the standard never changed, and because the
voltage needs of many chips in a computer change every year as they
energy efficient themselves. But the changing voltage needs of chips are
by voltage regulator modules (VRMs) that computer manufacturers put on
motherboards. These VRMs take one of these voltages (say, 5V) and
them down to the actual voltage needed (say, 1.7V) making multiple
capability of power supplies unnecessary.
Providing multiple output voltages complicates the design of power
supplies, and it
makes it harder to build efficient power supplies. In essence,
manufacturers have to
build four different power supplies: one each for +12V, -12V, 5V, and
four power supplies in one.
Because each motherboard may draw different amounts of power on each
manufacturers overprovision the supply for each individual voltage in
support multiple options. Since power supplies are most efficient near
rated loads, this overprovisioning leads to lower efficiency. The VRMs
regulator modules) used internally are also a significant source of loss.
current efficiencies (including power supply and VRM losses) are in the
range today, i.e., power supplies use 65-80% more power than necessary.
Google servers, and the new PC standard we propose, use a simple 12V power
supply. The power supply generates a single voltage, and all other
by motherboard components will be generated on the motherboard itself via
The net result of these changes is a dramatic improvement in efficiency
the power supply and the regulators) to about 85%, at virtually no cost.
words, you wont have to pay more for a higher-efficiency PC, because the
supply is actually getting simpler, not more complicated. By spending
another $20 or
so extra, it is possible to use higher-quality components and achieve
You wont be able to buy such computers for a while, and Google isnt
selling you any. But were working with industry partners such as Intel
to make this
technology an open standard that everyone can use, and that all vendors
will adopt. Its the right solution technically, and the right thing to
do for the
If you'd like us to keep you posted on our progress, please send us a
efficient-psu at google.com.
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