ICT ENERGY CONSUMPTION – TRENDS AND CHALLENGES
ICT ENERGY CONSUMPTION – TRENDS AND CHALLENGES
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发表时间：
2008
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通讯作者：
G. Fettweis;E. Zimmermann
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作者：
G. Fettweis;E. Zimmermann
信息和通信技术(信通技术)系统是当今知识社会的核心。这一领域的创新正在以极快的速度得到适应，近年来，全球对信通技术的使用激增。然而，这种史无前例的增长是有代价的：同时，ICT系统造成的二氧化碳排放量与全球航空旅行的排放量相同。如果信息和通信技术系统的能源消耗继续以目前的速度增长，将危及减少二氧化碳排放和应对气候变化的雄心勃勃的计划。因此，提高信息和通信技术系统的能效显然是今后几十年的主要研发挑战。一、信息和通信技术市场趋势很少有技术创新像互联网的大规模使用和个人移动通信的引入那样迅速和深刻地改变日常生活。在过去的二十年里，两者都从小众市场应用程序成长为全球可用的日常生活组件：第一个GSM电话呼叫于1991年在芬兰进行-仅15年后就有超过20亿GSM用户[1]。2007年11月，地球上每隔一位居民就拥有一部移动电话[2]。在同一时间跨度内，互联网服务器的数量增长了大约1000倍：从37.6万增加到3.95亿。这两个发展背后的驱动力是，并将继续是“摩尔定律”(或更确切地说，ITRS路线图)，根据该定律，CPU的处理能力和大容量存储设备的容量大约每18个月翻一番。这反过来又使更强大的信息和通信技术系统的使用对大众市场具有吸引力。为了能够在可接受的时间内将这种呈指数级增长的可用数据量传输给用户，(有线)互联网和无线网络(包括蜂窝、WLAN和WPAN)中的数据传输速率一直在以相同的速度增长-大约每5年增长10倍，如图1所示。信息社会的许多成就都建立在信息技术的全球成功基础上，微电子技术的创新使之成为可能。在过去的几年里，ICT系统不仅为台湾、韩国和新加坡等前发展中国家带来了巨大的经济繁荣，而且也是美国和欧盟等发达国家BIP增长的至少四分之一的来源。信息和通信技术的使用非但没有打开第一世界和第三世界之间的“数字鸿沟”，反而导致了相反的结果。二、信息和通信技术能源消费趋势数据速率和市场渗透率的巨大增长所付出的代价是，信息和通信技术系统的电力需求不断上升--尽管其速度远低于“摩尔定律”。如图2和图3所示，在作为互联网核心单元的服务器群[6]以及移动通信系统[7]中，过去几年的能耗每年都上升了16%-20%，相当于每4-5年翻一番。作为这一发展的结果，服务器群每年消耗约1800亿千瓦时的电力--超过全球电力消耗的1%。这相当于6000万个家庭的典型年用电量--超过欧盟家庭数量的三分之一。1基于[6]中的数据，2006年和2007年增长了20%。世界范围的电力消费和生产数据取自[8]。1995 200
Information and communications technology (ICT) systems are the core of today’s knowledge based society. Innovations in this area are adapted at tremendous speed and worldwide use of ICT has soared in recent years. However, this unprecedented growth comes at a price: ICT systems are meanwhile responsible for the same amount of CO2 emissions as global air travel. If the growth of ICT systems energy consumption continues at the present pace, it will endanger ambitious plans to reduce CO2 emissions and tackle climate change. Increasing the energy efficiency of ICT systems is thus clearly the major R&D challenge in the decades to come. I. ICT MARKET TRENDS Rarely have technical innovations changed everyday life as fast and profoundly as the massive use of the Internet and introduction of personal mobile communications. In the past two decades both grew from niche market applications to globally available components of daily life: The first GSM phone call took place 1991 in Finland – only 15 years later there were over 2 billion GSM users [1]. In November 2007, every second inhabitant of this planet possessed a mobile telephone [2]. In the same time span, the number of internet servers rose by roughly a factor of 1000: from 376’000 to 395 million [3]. The driving force behind these two developments was, and continues to be, "Moore's Law" (or rather the ITRS roadmap), according to which both the processing power of CPUs and the capacity of mass storage devices doubles approximately every 18 months. This in turn renders the use of ever more powerful ICT systems attractive for the mass market. In order to be able to transport this exponentially rising amount of available data to the user in an acceptable time, the data transmission rates both in the (wired) internet and wireless networks (including cellular, WLAN and WPAN) have been rising at the same speed – by about a factor 10 every 5 years, as illustrated in Figure 1. Many achievements of information society are based on the global success of information technology which has been made possible by innovations in microelectronics. In the last years, ICT systems have been responsible for the enormous economic boom not only of former developing countries like Taiwan, South Korea and Singapore, they have also been the source of at least a fourth of the BIP growth of developed nations like the United States [4] and the European Union [5]. Instead of opening up a "digital divide" between the first and the third world, the use of ICT has so far lead to the opposite. II. ICT ENERGY CONSUMPTION TRENDS The price paid for this enormous growth in data rates and market penetration is a rising power requirement of ICT systems – although at a substantially lower speed than "Moore's Law". Both in server farms as core units of the internet [6], as well as in mobile communications systems [7], a rise of the power consumption of 16-20% per year can be observed in the last years, corresponding to a doubling every 4-5 years, as illustrated by Figures 2 and 3. As result of this development, server farms meanwhile consume approximately 180 billion kWh of electricity per year – over 1% of the world-wide electricity consumption. This corresponds to the typical yearly electricity consumption of 60 million households – over a third of the number of households in the EU. 1 Based on the data from [6] and a 20% increase for 2006 and 2007. World wide electricity consumption and production data taken from [8]. 1995 200