On Route 101, the freeway that forms the spine of Silicon Valley, a ticker display on an advertising billboard counts up the billions of dollars鈥� worth of electricity wasted by companies that still use inefficient, power-hungry technology to power their search engines, web servers and video streaming networks.
Though the steadily climbing 10-figure numbers, which are heading for the $2 billion mark, are an advertisement for the new processor from Advanced Micro Devices, the sheer size of the numbers throws into stark relief an issue many online businesses hope will go away: the astronomical energy demand of today鈥檚 computers.
As microprocessors become faster, with more and more processor units, their energy needs, and the power required to cool them, have skyrocketed. Mark Mills, an analyst with Digital Power Group, a Washington DC-based energy research firm, says computers now consume about 10 per cent of the electricity generated in the US 鈥� and that figure is set to double in the next decade.
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Why is this happening? It鈥檚 not a straightforward case of proliferating desktop PCs sucking up more power. What鈥檚 at the root of the power consumption hike is a seismic shift in how we use computers, with online activity at the heart of it. As applications offering video access, music, photo storage and even word processing move the data off our desks and onto remote servers, a power-hungry beast is emerging: the data centre 鈥� sometimes called a server farm 鈥� that has to store and retrieve all your stuff.
鈥淭he creation, storage and movement of 10 megabytes of data uses nearly a kilo of coal鈥�
Of course there have been plenty of servers around for years, but until fairly recently they were only really needed during working hours. Now data centres are running 24 hours a day, 7 days a week delivering music, videos, emails, web pages and blogs to online audiences around the world.
To do so, servers in the US alone are already using more electricity than 1.3 million homes 鈥� some 14.8 terawatt-hours per year, according to 2004 figures from the California-based Electric Power Research Institute. In terms of the individual user, an energy-use audit by Mills and his colleagues found that the creation, packaging, storage and movement of just 10 megabytes of data 鈥� from the making of the hardware to the running of the system that delivers it to you 鈥� requires the energy equivalent of burning 900 grams of coal.
In 1985, a team at the US Department of Energy鈥檚 Lawrence Berkeley National Laboratory (LBL) in California began an experiment to see if they could reduce the energy needs of their own 80-hectare facility. The group took measures such as installing energy-efficient lighting, improving ventilation systems and replacing old, inefficient magnets on the lab鈥檚 particle accelerator. By 1995, they had reduced power consumption by 40 per cent.
Buoyed by that success, LBL formed a troubleshooting squad, dubbed the 鈥淎-team鈥�, which hosts public demonstrations on how to cut energy consumption in high-tech buildings, including biotech labs, clean rooms and, most recently, the data centres web users depend on.
An LBL report on data-centre efficiency released this week details measures that it claims could save internet businesses billions of dollars a year. Those savings will come, in large part, by either finding ways to reduce the energy lost as heat, or enabling machines to run more efficiently by keeping them cool.
Computers, like nearly all electronic devices, need a steady, non-fluctuating direct current (DC) power supply, which needs to be converted or 鈥渞ectified鈥� from the alternating current of the electricity grid. However, rectifiers are very inefficient and waste a lot of energy as heat.
In a typical data centre, this AC to DC conversion is made time after time, inside every single server, of which there may be many thousands. If this was done before the current reaches the servers, so getting rid of the rectifier in each one, the waste heat it generates could be released outside the data centre, significantly reducing cooling costs, LBL says.
What鈥檚 more, in a typical data centre current from the grid is first converted to DC to keep a giant back-up battery pack charged up then, beyond the batteries, it is converted back to AC before it reaches the servers. At present, servers can only use AC; what LBL wants is for the computer industry to develop servers ready for high-voltage DC power only 鈥� so they can all plug into the same DC supply and reduce conversion losses by only switching to DC once.
In tests using specially rigged DC-only servers working in a typical data centre configuration at a Sun Microsystems warehouse in Newark, California, the A-team showed they can reduce the energy needed to power and cool a data centre鈥檚 servers by up to 28 per cent.
More than 20 companies, including Silicon Valley titans Cisco and Intel, have donated equipment and labour for such LBL demonstrations. William Tschudi, who leads LBL鈥檚 team, says he has spoken to several firms about installing DC-powered servers and hopes that data centre companies will soon begin their own tests.
Not everyone is convinced that DC power is the answer. 鈥淭he design consultants I talk to say it鈥檚 not an option, it鈥檚 too expensive,鈥� says Rakesh Kumar of Connecticut market research firm Gartner. It would involve a wholesale redesign of the power supply networks inside data centres, he says.
A more practical solution, he suggests, is the use of liquid cooling to make servers run more efficiently, with fluid circulating through server racks like they already do in many types of supercomputers. The heat could then be recycled. According to Kumar, one UK university is already considering using this heat to warm a nearby city swimming pool.
Liquid cooling will soon be essential in data centres anyway, Kumar believes: 鈥淲e already have nearly three times the amount of heat today than air conditioning can handle and that鈥檚 not even considering the next generation of high-density servers,鈥� he says.
DC power and liquid cooling are not the only ways to reduce energy consumption and keep data centres cool. Smart chip design can help. Advanced Micro Devices, for instance, reversed the trend of ever-increasing power consumption when it introduced its Opteron processor in 2003. Opteron was markedly more efficient than any of its predecessors and, after it was upgraded in 2005, was able to increase computing capacity by 80 per cent with almost no increase in energy consumption.
In California, the utility company Pacific Gas and Electric is offering rebates of up to $4 million to individual data centres if they can reduce the number of servers they run. A server running at a quarter of its capacity consumes the same amount of power as one running at full stretch, so a process called virtualisation is used to enable individual servers to run multiple applications simultaneously, allowing data centres to run fewer computers, each operating at higher capacity.
As well as attempting to reduce energy use, internet giants Microsoft, Google and Yahoo are also relocating data centres to where energy is cheapest. The trio are building new centres in the US鈥檚 Pacific north-west, where electricity from hydropower is a fraction of the cost of power in California, where the majority of the country鈥檚 data centres remain.
鈥淭here isn鈥檛 one silver bullet out there that is going to solve this problem鈥�, says Tschudi, 鈥渂ut there are a lot of promising ideas.鈥�
