提高世界煤炭船队的效率，减少二氧化碳排放Upgrading the Efficiency of the World’s Coal Fleet to Reduce CO 2 Emissions

一个多世纪以来，煤和其他燃料中的能源一直被用来产生蒸汽发电。今天，由于全球人口不断增长，城市化和工业化程度不断提高，以及消除能源贫困的努力，快速发展国家的能源需求主要由煤炭推动。根据英国石油公司（BP）对2014年世界能源的统计报告，2000年至2013年间，煤炭在全球能源消费中所占份额攀升至30.1%，为1970年以来的最高水平。中国古代哲人常说，讲到物质，就讲到得失，而在人的事务中，有利有弊，能源的生产和利用是人的根本事务。不可否认，煤炭支持了工业化、现代文明的发展，但也存在着挑战，如二氧化碳等排放。许多清洁煤技术都是商用的，高效、低排放（HELE）燃煤电厂必须在向更清洁、低碳能源的未来过渡中发挥重要作用。用超超临界电站取代或改造低效亚临界电站，可使单位电力碳排放量减少约20%或以上。虽然要实现国际减缓气候变化的目标，可能需要进一步削减，但全球HELE技术的部署是一个可以立即产生重大影响的步骤。根据国际能源机构，只有约29%的现有燃煤发电机组可以进行碳捕获、利用和储存改造。因此，提高效率是实现重大减排的第一步。中国正通过积极提高其煤炭发电机组的效率来进行必要的投资。该国已经看到了相当大的改善，用使用HELE技术的大型电厂取代了旧的、效率低下的和较小的电厂。例如，上海外高桥3号超超临界燃煤电厂的标准排放量不到中国天然气发电厂限值的一半。还有一些非传统的提高能源利用效率的方法正在构想和部署之中。例如，以煤炭为基础的电、热、燃料多联产可以解决中国交通和工业部门的排放问题，从而实现全面的能源转型。此外，世界上第一台600兆瓦超临界循环流化床的示范，为低阶煤、废弃物和生物质的高效利用奠定了基础。在南非，一家独立的电力生产商正寻求利用煤炭地下气化提供急需的基本负荷电力。这一问题的基石是集中在许多方法，煤炭可以用来填补全球能源需求的最高效率和最低的排放量可能。因此，我们希望本期的内容能够引发对HELE技术这一重要课题的深入探讨。我代表编辑组，希望你们喜欢。

For well over a century the energy in coal and other fuels has been used to  create steam for electricity generation. Today, due to a continuously expanding global population, increasing urbanization and industrialization, and energy  poverty eradication efforts, energy demand is growing—fueled primarily by coal in  rapidly developing countries. According to BP’s Statistical Review of World Energy  2014, coal’s share of global energy consumption climbed between 2000 and 2013,  to 30.1%, the highest amount since 1970. Ancient Chinese philosophers often said that when speaking of material things, one  speaks of gains and losses, while in human affairs there are pros and cons—energy production and utilization is a fundamental human affair. There is no denying  that coal has supported the development of an industrialized, modern civilization,  but there are also challenges, such as CO2 and other emissions. Numerous clean  coal technologies are commercially available and high-efficiency, low-emissions (HELE) coal-fired power plants must play an important role in the transition to a  cleaner, lower-carbon energy future. Replacing or retrofitting a low-efficiency subcritical plant with an ultra-supercritical  plant could reduce carbon emissions per unit of electricity by about 20% or more.  While deeper reductions may be necessary to meet international climate mitigation goals, global HELE technology deployment represents a step that can have an  immediate, substantial impact. According to the International Energy Agency, only  about 29% of the existing coal-fired power fleet can be retrofitted for carbon capture, utilization, and storage. Thus, efficiency improvements are the first step on the  road to major emissions reductions.  China is making the needed investment by actively increasing the efficiency of its  coal-based power fleet. The country has already witnessed considerable improvements by replacing older, inefficient, and smaller power plants with large ones using  HELE technologies. For instance, criteria emissions from the Shanghai Waigaoqiao  No. 3 ultra-supercritical coal-fired power plant are less than half of China’s limits for  natural gas power plants.  There are also unconventional approaches to improving the efficiency of energy  utilization that are now being conceptualized and deployed. For example, coalbased polygeneration of electricity, heat, and fuel could address emissions from the  transportation and industrial sectors in China—leading to a comprehensive energy  transformation. In addition, the demonstration of the world’s first 600-MWe supercritical circulating fluidized bed has set the stage for the HELE utilization of low-rank  coals, wastes, and biomass. In South Africa one independent power producer is  looking to HELE underground coal gasification to provide much needed baseload  electricity.  This issue of Cornerstone is focused on the many ways that coal can be used to  fill global energy demand with the highest efficiency and lowest emissions possible. Thus, our hope is the content in this issue will spark deep engagement on the  important topic of HELE technologies. On behalf of the editorial team, I hope you  enjoy it.