TY - JOUR A1 - Schäppi, Remo A1 - Rutz, David A1 - Dähler, Fabian A1 - Muroyama, Alexander A1 - Haueter, Philipp A1 - Lilliestam, Johan A1 - Patt, Anthony A1 - Furler, Philipp A1 - Steinfeld, Aldo T1 - Drop-in fuels from sunlight and air JF - Nature : the international weekly journal of science N2 - Aviation and shipping currently contribute approximately 8% of total anthropogenic CO2 emissions, with growth in tourism and global trade projected to increase this contribution further(1-3). Carbon-neutral transportation is feasible with electric motors powered by rechargeable batteries, but is challenging, if not impossible, for long-haul commercial travel, particularly airtravel(4). A promising solution are drop-in fuels (synthetic alternatives for petroleum-derived liquid hydrocarbon fuels such as kerosene, gasoline or diesel) made from H2O and CO2 by solar-driven processes(5-7).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(8), and can deliver truly carbon-neutral fuels if the required CO2 is obtained directly from atmospheric air(9) . If H2O is also extracted from air(10), feedstock sourcing and fuel production can be colocated in desert regions with high solar irradiation and limited accessto 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 H2O and CO2 captured directly from ambient air to the synthesis of drop-in transportation fuels (for example, methanol and kerosene), with a modular 5 kW(thermal) 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. KW - chemical engineering KW - hydrogen energy KW - mechanical engineering KW - solar fuels KW - solar thermal energy Y1 - 2021 U6 - https://doi.org/10.1038/s41586-021-04174-y SN - 0028-0836 SN - 1476-4687 VL - 601 IS - 7891 SP - 63 EP - 80 PB - Macmillan Publishers Limited, part of Springer Nature CY - Berlin ER - TY - JOUR A1 - Lilliestam, Johan A1 - Patt, Anthony A1 - Bersalli, Germán T1 - On the quality of emission reductions BT - observed effects of carbon pricing on investments, innovation, and operational shifts. A response to van den Bergh and Savin (2021) JF - Environmental and Resource Economics N2 - To meet the Paris Agreement targets, carbon emissions from the energy system must be eliminated by mid-century, implying vast investment and systemic change challenges ahead. In an article in WIREs Climate Change, we reviewed the empirical evidence for effects of carbon pricing systems on technological change towards full decarbonisation, finding weak or no effects. In response, van den Bergh and Savin (2021) criticised our review in an article in this journal, claiming that it is "unfair", incomplete and flawed in various ways. Here, we respond to this critique by elaborating on the conceptual roots of our argumentation based on the importance of short-term emission reductions and longer-term technological change, and by expanding the review. This verifies our original findings: existing carbon pricing schemes have sometimes reduced emissions, mainly through switching to lower-carbon fossil fuels and efficiency increases, and have triggered weak innovation increases. There is no evidence that carbon pricing systems have triggered zero-carbon investments, and scarce but consistent evidence that they have not. Our findings highlight the importance of adapting and improving climate policy assessment metrics beyond short-term emissions by also assessing the quality of emission reductions and the progress of underlying technological change. KW - Carbon pricing KW - Climate policy KW - Decarbonisation KW - Technological change KW - Energy transition Y1 - 2022 U6 - https://doi.org/10.1007/s10640-022-00708-8 SN - 0924-6460 SN - 1573-1502 VL - 83 IS - 3 SP - 733 EP - 758 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Lilliestam, Johan A1 - Patt, Anthony A1 - Bersalli, German T1 - The effect of carbon pricing on technological change for full energy decarbonization BT - a review of empirical ex-post evidence JF - Wiley interdisciplinary reviews : Climate change N2 - In order to achieve the temperature goals of the Paris Agreement, the world must reach net-zero carbon emissions around mid-century, which calls for an entirely new energy system. Carbon pricing, in the shape of taxes or emissions trading schemes, is often seen as the main, or only, necessary climate policy instrument, based on theoretical expectations that this would promote innovation and diffusion of the new technologies necessary for full decarbonization. Here, we review the empirical knowledge available in academic ex-post analyses of the effectiveness of existing, comparatively high-price carbon pricing schemes in the European Union, New Zealand, British Columbia, and the Nordic countries. Some articles find short-term operational effects, especially fuel switching in existing assets, but no article finds mentionable effects on technological change. Critically, all articles examining the effects on zero-carbon investment found that existing carbon pricing scheme have had no effect at all. We conclude that the effectiveness of carbon pricing in stimulating innovation and zero-carbon investment remains a theoretical argument. So far, there is no empirical evidence of its effectiveness in promoting the technological change necessary for full decarbonization. This article is categorized under: Climate Economics > Economics of Mitigation KW - carbon pricing KW - climate policy KW - decarbonization KW - technological change Y1 - 2020 U6 - https://doi.org/10.1002/wcc.681 SN - 1757-7780 SN - 1757-7799 VL - 12 IS - 1 PB - Wiley CY - Hoboken ER -