Energy Use for Electricity Generation Requires an Assessment More Directly Relevant to Climate Change
Energy Use for Electricity Generation Requires an Assessment More Directly Relevant to Climate Change
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DOI：
10.1021/acsenergylett.0c02093
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发表时间：
2020-10
影响因子：
22
通讯作者：
B. Logan;R. Rossi;Gahyun Baek;Le Shi;J. O’Connor;W. Peng
中科院分区：
文献类型：
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作者：
B. Logan;R. Rossi;Gahyun Baek;Le Shi;J. O’Connor;W. Peng
除非我们迅速减少化石燃料的消耗，否则未来几年气候变化将有增无减。COVID - 19大流行将暂时减少总体能源消耗，但这种情况不会持续下去。例如，在美国，根据美国能源情报署（EIA）的报告，与2019年相比，2020年前六个月的用电量减少了5%，总能源使用量减少了8.5%，预计全年全球减少8%。继1973年的第一次石油危机、1979年的第二次石油危机和几次全球经济衰退之后，全球发生了一系列暂时减少能源消耗的事件，新冠肺炎疫情只是其中最新的一次。每一次能源消耗都出现反弹，能源使用都在不断升级。考虑到之前的这些破坏，我们可以预期，能源使用将再次回到大流行前的水平，气候变化将继续下去，除非我们采取具体措施避免化石燃料消费造成的二氧化碳排放的再次增长。技术上的解决方案是存在的，但它们需要更广泛的公众支持。为了更好地告知政策制定者和公众，我们需要更清晰的方式来展示和解释能源使用，特别是在电力部门。在此，我们建议在向公众传达能源使用情况的方式上需要做出一些改变，从独立于化石燃料术语的能源单位开始，根据生产它所消耗的化石燃料的数量清楚地显示用电量，并建立一条明确的途径，使能源消耗最少地使用导致二氧化碳和其他温室气体排放的过程。以不以燃料燃烧为基础的单位传达能源使用。报告能源使用的一个混淆因素是各种各样的能源单位及其燃料燃烧的背景。能源使用将需要越来越多地依赖碳中性来源，因此能源单位不应与燃料燃烧相关的术语联系在一起（或使用非si单位）。EIA使用的能量单位目前以四单位的热值表示（1千万亿英热单位或qBtu，其中1 quad = 10 Btu）。这些能源单位与利用可再生能源实现电力基础设施缺乏相关性，而不是通过燃烧燃料来加热水产生的电力。同样，应避免以油热值为基础的能源单位。国际能源协会（IEA）和其他机构报告的能源单位为百万吨石油当量（Mtoe），其中1吨石油当量= 10千卡，大致相当于1吨石油的热量。在讨论大量电能时，十亿千瓦时（或太瓦时，TWh）的能量单位是有意义的，但在讨论石油和天然气等燃料中的能量时，这些单位并不适用。在这里，我们提倡使用焦耳（EJ，或10 J）来描述大规模的能源使用，因为这些单位不参考石油或暗示能源生产的燃料转换（1 EJ = 0.948 quad = 2.39 × 10 Mtoe = 278 TWh）。此外，美国和许多其他国家的用电量在100 EJ左右或更少，这为各国之间的能源比较提供了一个方便的指标。避免夸大可再生能源发电所使用的能源。许多关于电力生产的报告强调与化石燃料工厂效率相关的初级能源使用，这意味着即使不使用燃烧过程的技术也会消耗燃料。美国环境影响评估署和其他机构夸大了可再生能源的一次能源使用量，因为它们增加了传统化石燃料蒸汽厂生产这么多电力所浪费的能源。例如，2019年，美国使用了2.37 EJ的太阳能、风能、水能和地热能产生的电力，但EIA报告称，根据化石燃料发电厂的平均能源效率（37.5%），用于生产这些电力的一次能源为6.33 EJ。使用这种基于化石燃料效率的方法可能会误导公众对实际生产和消耗的可再生能源的数量以及发电和二氧化碳排放之间的关系。不需要报告可再生技术的主要能源，这里定义为包括太阳能、风能、水力和地热，因为没有燃料消耗（不燃烧产生热量）。来自阳光、风、
Climate change will continue unabated in the coming years unless we rapidly reduce consumption of fossil fuels. The COVID pandemic will provide temporary reductions in overall energy consumption, but this will not last. In the United States, for example, in the first six months of 2020 there was a 5% reduction in electricity and 8.5% reduction in total energy use reported by the U.S. Energy Information Administration (EIA) compared to 2019, with an estimated 8% global reduction for the year. The COVID pandemic is just the newest of a series of global events that have temporarily reduced energy consumption, such as the first oil crisis in 1973, the second one in 1979, and several global economic recessions. Each time energy consumption rebounded and energy use continued to escalate. Considering these previous disruptions, we can therefore expect that energy use will again return to prepandemic levels and climate change will continue unless we do something specifically to avoid the regrowth of CO2 emissions from the consumption of fossil fuels. Technical solutions exist, but they need more widespread support from the public. To better inform policy makers and the public we need clearer ways to present and explain energy use, particularly as it applies to the electric power sector. We suggest here that several changes are needed in the way we convey energy use to the public, beginning with energy units independent of fossil fuel terminologies, electricity use being clearly presented in terms of the amount of fossil fuel consumed to produce it, and a clear path being established that enables energy consumption with minimal use of processes that contribute to CO2 and other greenhouse gas emissions. Convey energy use in units that are not based on combustion of fuels. A confounding factor in reporting energy use is the wide variety of energy units and their context of fuel combustion. Energy use will need to increasingly rely on carbon-neutral sources, so energy units should not be tied to terminology anchored to fuel combustion (or use non-SI units). The energy units used by the EIA are currently expressed in heating values in quads (a quadrillion British thermal units or qBtu, where 1 quad = 10 Btu). These energy units lack relevance for achieving an electrical energybased infrastructure using renewable sources, as opposed to electricity generated by burning fuels to heat water. Similarly, energy units based on oil heating values should be avoided. The International Energy Association (IEA) and others report energy in million tonnes of oil equivalent (Mtoe), where 1 toe = 10 kilocalories or roughly the heat content of 1 tonne of oil. Energy units of billion kilowatt hours (or terawatt hours, TWh) make sense when discussing large amounts of electrical energy, but these units are not applied when discussing energy in fuels such as oil and natural gas. Here, we advocate the use of exajoules (EJ, or 10 J) to describe large-scale energy use as these units do not reference oil or imply fuel conversions for energy production (1 EJ = 0.948 quad = 2.39 × 10 Mtoe = 278 TWh). In addition, the amount of electricity used by the United States and many other countries is around 100 EJ or less, providing a convenient metric for energy comparisons among countries. Avoid exaggeration of energy used for electricity production from renewables. Many reports on electricity production emphasize primary energy use that is tied to fossil fuel plant efficiencies, implying fuel consumption even for technologies that do not use combustion-based processes. The EIA and others exaggerate primary energy use for renewables by adding an amount of energy that would be wasted by a conventional fossil fuel steam plant to produce that amount of electricity. For example, in 2019 the United States used 2.37 EJ of electricity produced from solar, wind, hydro, and geothermal energy, but the EIA reported that 6.33 EJ of primary energy was used to produce this electricity based on average energy efficiencies (37.5%) for fossil fuel plants. Using this approach based on fossil fuel efficiencies could mislead the public about the amount of renewable energy actually produced and consumed and the relationships between electricity generation and CO2 emissions. There is no need to report primary energy for renewable technologies, defined here to include solar, wind, hydro, and geothermal, because there is no fuel consumption (no combustion to generate heat). Energy from sunlight, wind,