How Green is Your Valley?
Pete Singer Editor-in-Chief
The global explosion in IT, combined with rapidly escalating energy costs, has chipmakers asking how much does it really cost to run today’s computers/servers, and what can be done to provide more energy-efficient solutions?
Statistics gathered from the last few years show an alarming trend. Aggregate electricity use for servers doubled over the period of 2000 to 2005, both in the United States and worldwide, according to a 2007 study, “Estimating Total Power Consumption By Servers In The U.S. And The World.“ Total power used by servers represented ˜0.6% of total U.S. electricity consumption in 2005. When cooling and auxiliary infrastructure are included, that number grows to 1.2%, an amount comparable with that for color televisions. The total power demand in 2005 (including associated infrastructure) is equivalent (in capacity terms) to about five 1000 MW power plants for the United States and 14 such plants for the world.
At SEMI’s Industry Strategy Symposium (ISS) conference in January, Rand Bane, vice president and chief economist at Applied Materials noted that data center electricity use has expanded rapidly, growing from 28.2 billion kilowatt hours per year (kWh/year) in 2000 to 61.4 billion kWh/year in 2006. If this trend continues, energy use for data centers could balloon to more than 120 billion kWh per year by 2011.
The good news is that chipmakers have developed low-power ICs for mobile applications to prolong battery life, largely focusing on reducing the leakage current (with high-k/metal gates for example) and by reducing supply voltages and threshold voltage variability. An alternative scenario, where “greener“ state-of-the-art low power microprocessors and memory are employed, results in a more manageable 70 billion kWh/year for a data center. Rising energy costs will only fuel the demand for these newer chips, as the IT industry looks for ways to reduce costs as IP traffic soars.
In addition to new, lower power data centers, Bane also sees opportunities in the unified “smart grid,“ as well as solar power. A highlight of the recent US-China Clean Energy Forum was a demonstration of how solar technologies tie together in the real world — integrating a parking lot-based solar array, electric vehicles, smart grid technology, energy storage, and high-performance battery recharging systems.
In addition to supplying chips with reduced power consumption requirements, the semiconductor industry also has some significant opportunities to be more green when it comes to manufacturing processes.
A semiconductor manufacturing fab can consume as much electricity in a year as 10,000 homes (170,000 MW) and up to 3 million gallons of water per day. Annual utility bills can be as high as $20M???$25M. Photovoltaic manufacturing plants, although trying hard to appear as green, have similar numbers and also consume massive quantities of chemicals and gases, some of which — such as NF3 used for chamber cleaning — are notoriously bad for the environment.
The good news is that new semiconductor manufacturing and PV fabs are looking to not only reduce electricity and water use, but also aim to reduce global warming emissions, volatile organic compounds (VOCs) and hazardous materials.
A recently announced collaborative effort in this area is worthy of mention. The university research consortium Semiconductor Research Corp. has brought onboard European nanoelectronics R&D consortium IMEC to join work in creating “environmentally friendly“ processes and materials for advanced semiconductor manufacturing.
The SRC and IMEC will target two objectives: creation of leading-edge technologies that protect the environment, and more effective processes for lowering the costs of chip manufacturing. The proposed first phase of the project will focus on sustainable cleaning and surface preparation of new materials and nanostructures, including integration of new channel and gate materials (e.g., Ge and III/V precursors), and establishing options for minimizing emissions and decreasing usage of chemicals, water, and energy. Also addressed will be in-line and real-time approaches for monitoring efficacy of nanostructure cleaning processes. A second phase will explore sustainable high-performance material planarization processes, aiming to advance design and feasibilty of process options that eliminate release and discharge of nanoparticles in manufacturing waste streams.
It’s great to see an awareness of environmental issues and the actions being taken. We’ll keep you updated at www.solid-state.com and the newly launched www.pvworld.com. Check it out!