What cell phones can teach us about energy efficiency

1Executive Summary

Over the years, cell phones have been uniquely designed to operate as efficiently as possible, quickly moving in and out of states of power — from sleep to low power to full power — and utilizing the latest battery innovations. Because of this, new energy technologies commonly introduced first in cell phones are now being mimicked across other industries, leading to information technology and transportation that is more energy efficient.

According to The Climate Group, information and communication technology (ICT) accounts for about 2 percent of the world’s greenhouse gas emissions. Within that ICT footprint, home computers and peripherals account for 49 percent, while cell phones are responsible for only 3 percent. Computers are power hungry machines, after all, and they’re plugged in much of the time. In contrast, cell phones have been designed from the ground up to be energy efficient and are largely used on the go and could serve as a model for other areas of technology when it comes to energy savings.

You got served

Take servers, for example. The latest trend for building low-power server technology is to take low-power ARM chips — commonly used in cell phones — and design them into server boxes that use much less power. The idea is that basic web services that don’t require all that much server work (for example, static websites) can easily use lower-power servers instead of higher-power ones to stay up and running. (Or to use an analogy, you don’t need a rocket ship engine to drive your VW Bug to the corner store for milk.)

Startup Calxeda has been spearheading this trend, and the company’s specialty servers use 120 ARM quad-core nodes with an average consumption of 5 watts per node. In comparison, Intel and AMD’s competing server tech, which uses the standard x86 architecture, consumes around 80 to 130 watts for a quad-core machine and down to 30 watts for a lower-power version. Lower power use, such as in Calxeda’s offering, means a lower energy bill for data center operators.

Calxeda’s tech won’t be out until 2012, but it has been bringing together partners that will work with its hardware, including Eucalyptus, Gluster, Canonical and Opscode. Calxeda plans to use Ubuntu’s Linux distribution as the operating system for its gear. However, even before the product launch, the idea of using ARM for servers has been making waves: Nvidia and Marvell are now also working on ARM-server tech, and analysts think that this combo could actually start to make a dent in the server market closer to 2015.

Electrifying transportation

Electric cars are another area where cell phones have played a key influencer role. That shouldn’t be surprising: EVs are essentially very large electronic devices, and cell phones are very small ones. But electric cars need to be as light as possible — and still carry their passengers and perform well — in order to have as much battery range as possible (the lighter the car, the farther it can drive on a single battery charge).

Lightweight tech is one area where cell phones can give advice to EVs. Electric carmaker Tesla Motors has not only been learning from the battery tech of mobile devices but has also been stringing together basically the same batteries to move its electric sports car, the Roadster. Tesla uses small-format lithium ion batteries found in laptops, which are a slightly smaller version of those used in cell phones, instead of large-format electric car batteries used by other carmakers.

Tesla’s use of these small, mobile batteries has been a crucial move that has given its speedy, tint sports car a 200-mile battery range. This has been the decade of innovation and economy of scale for small form-factor lithium ion batteries; Tesla is betting that such improvements mean that it can produce a much-lower-cost electric car in 2012 and 2013.

The ubiquity of cell phones has also produced a variety of technologies, such as materials and management software, that can direct and distribute the heat from batteries within devices. After all, when an electronic device overheats, it can be a safety problem and also kill the device.

Lightweight heat spreaders, for example, are something that could jump from cell phones to EVs. The iPhone uses a heat spreader made from a thin layer of graphite that is very light. It distributes heat evenly throughout the device and makes sure the touchscreen never gets too hot. GrafTech International, a massive graphite electrode supplier, is moving this technology from cell phones like the iPhone to electric cars and will be selling it as a component for battery packs that could appear in retrofits of current electric vehicles as early as 2014.

Cell phones as power influencers

Cell phones will also continue to become more energy efficient. The Climate Group predicts that cell phones’ share of the ICT greenhouse gas footprint will drop from 3 percent to 1 percent by 2020, largely because of the greater use of smart chargers that stop the phone’s power draw when plugged in and fully charged. The Climate Group says that the bulk of energy that powers cell phones today is attributed to so-called vampire power, which is when cell phones are plugged in to an outlet and are fully charged but not in use.

As cell phones become ever more ubiquitous, consumers will look for phones that can run for longer without being charged. The developing world, in particular, could look to long battery life as a differentiating factor, given that the power grid is spotty or nonexistent in many countries.

Similar (and even more robust) smart chargers will particularly be needed for electric vehicles, especially if EVs ever become a mainstream product. Imagine if half of your neighborhood charged the 6,831 laptop-size battery cells in a Tesla Roadster once a day and that the charging was inefficient and wasteful. Talk about power overload.

From cars to computing, in the future everything will be connected to a network and will always be on. Devices need to be built from the ground up to use power only when they need it; smart software can manage power states and battery charging. In other words, if every device acted like a cell phone, we’d be in pretty good shape.

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