Schäppi Remo, Rutz David, Dähler Fabian, Muroyama Alexander, Haueter Philipp, Lilliestam Johan, Patt Anthony, Furler Philipp, Steinfeld Aldo
Department of Mechanical and Process Engineering, ETH Zurich, Zurich, Switzerland.
Institute for Advanced Sustainability Studies (IASS), Potsdam, Germany.
Nature. 2022 Jan;601(7891):63-68. doi: 10.1038/s41586-021-04174-y. Epub 2021 Nov 3.
Aviation and shipping currently contribute approximately 8% of total anthropogenic CO emissions, with growth in tourism and global trade projected to increase this contribution further. Carbon-neutral transportation is feasible with electric motors powered by rechargeable batteries, but is challenging, if not impossible, for long-haul commercial travel, particularly air travel. A promising solution are drop-in fuels (synthetic alternatives for petroleum-derived liquid hydrocarbon fuels such as kerosene, gasoline or diesel) made from HO and CO by solar-driven processes. Among the many possible approaches, the thermochemical path using concentrated solar radiation as the source of high-temperature process heat offers potentially high production rates and efficiencies, and can deliver truly carbon-neutral fuels if the required CO is obtained directly from atmospheric air. If HO is also extracted from air, feedstock sourcing and fuel production can be colocated in desert regions with high solar irradiation and limited access to water resources. While individual steps of such a scheme have been implemented, here we demonstrate the operation of the entire thermochemical solar fuel production chain, from HO and CO captured directly from ambient air to the synthesis of drop-in transportation fuels (for example, methanol and kerosene), with a modular 5 kW pilot-scale solar system operated under field conditions. We further identify the research and development efforts and discuss the economic viability and policies required to bring these solar fuels to market.
航空和航运目前约占人为二氧化碳排放总量的8%，随着旅游业和全球贸易的增长，预计这一占比还会进一步上升。使用可充电电池驱动的电动马达实现碳中和运输是可行的，但对于长途商业旅行，尤其是航空旅行而言，即便并非完全不可能，也是一项具有挑战性的任务。一种很有前景的解决方案是通过太阳能驱动的过程，利用氢气（H₂）和一氧化碳（CO）制成的替代燃料（如煤油、汽油或柴油等石油衍生液态烃燃料的合成替代品）。在众多可能的方法中，利用聚光太阳能辐射作为高温过程热的来源的热化学路径具有潜在的高生产率和效率，并且如果所需的一氧化碳直接从大气中获取，就能生产出真正的碳中和燃料。如果氢气也从空气中提取，那么原料采购和燃料生产可以集中在太阳能辐射高且水资源匮乏的沙漠地区。虽然该方案的各个步骤已得到实施，但在此我们展示了整个热化学太阳能燃料生产链的运行情况，即从直接从环境空气中捕获的氢气和一氧化碳到合成替代运输燃料（如甲醇和煤油），这是在野外条件下运行的一个模块化5千瓦中试规模太阳能系统实现的。我们还确定了研发工作，并讨论了将这些太阳能燃料推向市场所需的经济可行性和政策。
