剑桥大学工程师的最新分析表明，广泛应用纯电动汽车可使能源效率最大化，并具备二氧化碳减排潜力。

The widespread adoption of battery electric vehicles offers the greatest energy efficiency and potential for CO2 reduction, new analysis by Cambridge engineers has shown.

但他们警告，若要释放纯电动汽车的全部潜力，需改善电网以满足更高的电力需求，同时要加大充电桩的密度来缓解所谓的“里程焦虑”，即对可续航历程不足导致抛锚的担忧。这项发现发表在《应用能源》杂志上。

But they warn, that in order for the full potential of battery electric vehicles (BEVs) to be unlocked, grid improvements will be necessary to meet elevated electricity demand and work will need to be done to increase charging station availability to alleviate so-called “range-anxiety” – fear that occupants of BEVs will be left stranded due to insufficient range. Their findings are published in the journal Applied Energy.

使用纯电路径的纯电动汽车和使用氢气的燃料电池电动汽车是减少交通领域温室气体排放的两大前沿之选。

BEVs, using an all-electric pathway, and fuel-cell electric vehicles (FCEVs), requiring the use of hydrogen, are two of the forefront options for reducing the transport sector’s greenhouse gas emissions.

来自可持续道路运输中心的研究助理莫利·豪根博士与能源部能源研究小组的同事针对轻负荷汽车（即小汽车）和重型货车对这两种低碳选择的能源消耗进行了随机分析。

Dr Molly Haugen, Research Associate at the Centre for Sustainable Road Freight, and colleagues from the Department’s Energy research group, carried out a stochastic analysis of the energy consumption of both low-carbon options concerning light-duty (i.e. cars) and heavy-goods vehicles.

为了确定哪种能源路径是更好的选择，研究人员关注了适用于当前和未来能源系统的电力和氢动力道路运输的以下方面：

In order to determine which energy pathway is the better option, the researchers paid attention to the following areas for both electric and hydrogen powered road transport, applicable for both current and future energy systems:

他们的分析表明，纯电动汽车可以持续减少温室气体排放。轻型纯电动汽车的能源路径通过减少输入能源浪费来最大程度地减少CO2排放，比使用电网能源的燃料电池汽车的效率高65％。研究人员表示，随着电网脱碳和技术改进，通过这种途径可进一步减少二氧化碳的排放。重型纯电动货车在体积和有效载荷受限的情况下也能够实现较低的CO2排放，其中电动道路系统是最节能的途径。

Their analysis shows that BEVs provide sustained greenhouse gas reductions. The light-duty BEVs energy pathway minimises CO2 emissions by reducing input energy waste and is 65% more efficient than light-duty FCEVs using grid energy. As the grid decarbonises and the technology improves, the researchers say that further CO2 emissions reductions with this pathway will be possible. Battery heavy-good vehicles are also able to achieve a lower CO2 emission in both volume and payload limited circumstances, with electric road systems being the most energy efficient pathway.

同时，在拖车体积最大化的情况下，电动和燃料电池重型货车的一级能源预计碳强度相似。但是，与燃料电池重型货车相比，使用常规电池系统或电动道路系统的电动重型货车能够分别减少55％和67％的碳排放。

Meanwhile, in a maximised trailer volume scenario, electric and fuel-cell heavy-good vehicles have similar projected carbon intensities from a natural gas primary energy source. However, electric heavy-goods vehicles using conventional battery systems or an electric road system are able to achieve a 55% and 67% carbon reduction compared to fuel-cell heavy-goods vehicles, respectively.

相比之下，由于系统效率低下，燃料电池汽车所使用的氢气系统的碳足迹（每公里行驶）比电力系统高出2到3倍，而其对可再生能源的需求却比电力系统高2到3倍。

In comparison, the hydrogen system used by FCEVs has a carbon footprint (per km driven) that is two to three times higher due to the system’s inefficiency and which requires two to three times more renewable energy than an electric energy system.

豪根博士说：“虽然纯电动汽车和燃料电池汽车都是可以减少尾气排放的低碳选择，但总体效率，相关碳强度和成本有所不同。英国政府承诺在2050年前将所有温室气体排放量净降至零，随着最后期限越来越近，我们需要决定使用哪种途径（纯电或氢气）来集中利用资源，资金和研究。

Dr Haugen said: “Battery electric vehicles (BEVs) and fuel-cell electric vehicles (FCEVs) are low-carbon options that reduce tailpipe emissions, but differ in overall efficiency, associated carbon intensity, and cost. As we inch closer to the UK Government’s committed 2050 deadline, requiring the UK to bring all of its greenhouse gas emissions to net zero by this date, a decision needs to be made on which pathway – all-electric or hydrogen – to dedicate resources, funding and research.

“我们从能源到能量使用的角度评估了的电池电动和氢燃料电池汽车能源系统，并着重指出了系统在何处损失能量；组件如何影响整体系统效率；以及相关的二氧化碳排放量。由此可见，基于氢的能源系统将需要要么尚未实现商业化的技术（即具有碳捕获和存储功能的蒸汽甲烷），要么需要大量可再生能源。即使满足这些要求，任何氢能途径在英国的二氧化碳排放量都将比纯电途径高，并且需要两到三倍的一次能源。因此，利用可再生能源生产用于燃料电池的氢气，并在系统过程中浪费其中的60%，将阻碍可再生资源协助其他部门脱碳的能力。”

“We evaluated both battery electric and hydrogen fuel-cell vehicle energy systems, from energy source to energy use, and highlighted where the system is losing energy; how those components affect the overall system efficiency; and related CO2 emissions. From this, it is clear that a hydrogen-based energy system will require either a technology that has yet to take off commercially (namely, steam methane with carbon capture and storage) or significant renewable energy resources. Even if these requirements are met, any hydrogen energy pathway will have higher CO2 emissions than an all-electric pathway in the UK and will require two to three times more primary energy. With this, using renewable energy to produce hydrogen for fuel-cell use, and consequentially wasting approximately 60% of it to system processes, will hinder the ability of renewable resources to aid in decarbonising other sectors.”