介绍:
Digital Diet
Telecommuting, Internet shopping
and online meetings may save energy
as compared with in-person alternatives,
but as the digital age moves on,
its green reputation is turning a lot browner.
Last year, e-mailing consumed
as much as 1.5 percent of the nation's electricity
-half of which comes from coal.
Last year the computers of the world
ate up 123 billion kilo-watt hours of energy.
As a result, the power bill to run a computer
over its lifetime will surpass the cost
of buying the machine in the first place
-giving Internet and computer companies
a business reason to cut energy costs,
as well as an environmental one.
One of the biggest energy sinks comes
not from the computers themselves
but from the air-conditioning needed
to keep them from overheating.
For every kilowatt-hour of energy used
for computing in a data center,
another kilowatt-hour is required to
cool the furnace like racks of servers.
For Internet giant Google,
this reality has driven efforts such as
the installation of a solar array
that can provide 30 percent of the peak power
needs of its headquarters as well as
increasing purchases of renewable energy.
But to deliver Web pages within seconds,
the firm must maintain hundreds of
thousands of computer servers in the buildings.
"We are actively working to maximize the efficiency
of our data centers,
which account for most of the energy
Google consumes worldwide."
remarks Google's green energy principal Bill Weihl.
Google will funnel some of its profits into a new effort,
nicknamed RE<C
(for renewable energy cheaper than coal,
as Google translates it) to make sources such as
solar-thermal, high-altitude wind
and geothermal cheaper than coal "within years,
not decades," according to Weihl.
In the meantime, the industry as a whole has
employed a few tricks to save watts.
Efforts include rearranging the stacks of servers
and the mechanics of their cooling,
and using software to create multiple "virtual" computers,
rather than having to deploy several real ones.
Such virtualization has allowed computer maker
Hewlett-Packard to consolidate 86 data centers
spread throughout the world to just three,
with three backups, says Pat Tiernan,
the firm's vice president of social
and environmental responsibility.
The industry is also tackling the energy issue
at the computer-chip level.
Chipmakers such as Intel and AMD have shifted to
so-called multi-core technology,
which packs multiple processors into one circuit
rather than separating them.
"When we moved to multi-core
and throttled down microprocessors,
the energy savings were pretty substantial,"
says Allyson Klein, Intel's marketing manager.
Chipmakers continue to shrink circuits
on the nanoscale as well,
which "means a chip needs less electricity" to
deliver the same performance, she adds.
