Engineered for efficiency

The whole notion of ‘green data centres’ might be very popular on the political front, but why should a green data centre be any different from a well-engineered, energy-efficient one? asks Patrick Fogarty, a director at consulting engineering firm Norman Disney & Young.

In particular, he highlights the need to boost energy efficiency, rather than using renewables to ‘tick a political box’. “The way the grid is set up means that’s just displacing someone else’s energy,” he says.

Generating renewable energy onsite is particularly favoured by government, but Fogarty says while it’s feasible to generate 20% of a site’s requirements using a variety of renewables (such as wind, photo- voltaic, biodiesel and geothermal), the cost per kilowatt is prohibitive compared to plain good design.

“If you can achieve 25% savings [by increasing energy efficiency], that dwarfs anything you can get from renewables. You can get real savings through good engineering,” he says.

Lack of real action

The engineer, a specialist on data centre design, says he is surprised at the “lack of significant action”, despite ‘green’ having being a headline issue on the public and political agenda for some time.

“We need a reality check about what’s actually happened after two years of talking about it,” he says.

Fogarty says he sees lots of advertisements for “100% renewable data centres that run on woodchips and stuff like that. That might make a good story and raise awareness, but it doesn’t solve problems. These are either very small sites or large sites with grid-shared power – what is going on behind the scenes? Are they actually doing anything to reduce their energy [usage]? Twelve kilowatts from photocells is not helping when you have racks taking three times that.”

Engineering for efficiency

The problem, according to Fogarty, is that while the politics might be behind renewable energy, the numbers clearly aren’t. And while increasing energy efficiency is the best way to cut reliance on the grid, the media coverage of renewables tends to knock efficiency off the perch.

“[Green has] certainly got into people’s psyche, but while there’s good stuff out there, most of the publicity goes to big companies with social responsibility departments.”

The bottom line, however unmarketable, is that engineering for efficiency is still the best way to cut energy usage. “We need to start again and design for efficiency, rather than design for ‘green’,” he says.

Fogarty has plotted the path that electricity takes from power station to processor chip, and observed that the greatest loss of efficiency occurs during cooling.

“From power station to chip, it’s possible to knock off 80% of inefficiency. [For example] we don’t have to chill air if it’s cold outside. Sometimes the only reason chillers are there is because IT won’t allow incursion beyond the allowable temperature range.”

However political the discussion surrounding renewables, from an engineering perspective Fogarty concludes that any discussion of green data centres should focus on “keeping that chip doing [only] what it needs to do.”

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