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Abstract

While a rapid decommissioning of fossil fuel technologies deserves priority, most climate stabilization scenarios suggest that negative emission technologies (NETs) are required to keep global warming well below 2°C. Yet, current discussions on NETs are lacking a distinct energy perspective. Prominent NETs, such as bioenergy with carbon capture and storage (BECCS) and direct air carbon capture and storage (DACCS), will integrate differently into the future energy system, requiring a concerted research effort to determine adequate means of deployment. In this perspective, we discuss the importance of energy per carbon metrics, factors of future cost development, and the dynamic response of NETs in intermittent energy systems. The energy implications of NETs deployed at scale are massive, and NETs may conceivably impact future energy systems substantially. DACCS outperform BECCS in terms of primary energy required per ton of carbon sequestered. For different assumptions, DACCS displays a sequestration efficiency of 75-100%, whereas BECCS displays a sequestration efficiency of 50-90% or less if indirect land use change is included. Carbon dioxide removal costs of DACCS are considerably higher than BECCS, but if DACCS modularity and granularity helps to foster technological learning to <100$/tCO2, DACCS may remove CO2 at gigaton scale. DACCS also requires two magnitudes less land than BECCS. Designing NET systems that match intermittent renewable energies will be key for stringent climate change mitigation. Our results contribute to an emerging understanding of NETs that is notably different to that derived from scenario modelling.
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... Carbon dioxide removal options are not yet consistently considered in 100% RE systems research. The necessity to study net-negative CO 2 emission scenarios and a broader CDR portfolio that is integrated in long-term 100% RE scenarios is outlined in section IX.A. Teske/DLR et al. [125] integrated natural climate solutions (NCS) comprehensively, but their model lacked other CDR options such as direct air captured carbon and storage (DACCS) and bioenergy carbon capture and storage (BECCS) [377]. So far, only the LUT-ESTM has presented insights on DACCS [54], [378] among the models used for 100% RE systems research, while lacking the most important NCS. ...
... To represent this new energy sector in appropriate detail, comprehensive CDR/NET technology portfolios must be developed. For such technology portfolios, an assessment of technological and environmental limitations is indispensable [377], [398], [400], [401]. The second half of this century will also be very important for scaling the energy-industry-CDR system toward a truly sustainable system [144], [212], since about 10 billion people will expect standards of living comparable with the most developed countries as of today. ...
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... Depending on the modeling approach and scenario, these studies project that the DACCS deployment levels for meeting a 2°C or stricter climate target by 2100 can reach up to 40 Gt of annual CO 2 sequestration [16][17][18]20 . At this scale, DACCS (assuming a solvent-based process) could consume up to 12% and 60% global electric and non-electric energy by 2100 17,21 . Evidently, for DACCS facilities connected to electric power grids, their environmental performance will depend on the electricity system context in which they will operate. ...
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... In the near to medium term, there could be trade-offs between uses of renewable energy to power either new DACCS systems or global energy needs (Beuttler et al., 2019;Creutzig et al, 2019;Realmonte et al., 2019). Moreover, upscaling renewable energy would require tremendous material and spatial resources (Fuhrman et al., 2020). ...
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Thesis
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Book
This open access book presents detailed pathways to achieve 100% renewable energy by 2050, globally and across ten geographical regions. Based on state-of-the-art scenario modelling, it provides the vital missing link between renewable energy targets and the measures needed to achieve them. Bringing together the latest research in climate science, renewable energy technology, employment and resource impacts, the book breaks new ground by covering all the elements essential to achieving the ambitious climate mitigation targets set out in the Paris Climate Agreement. For example, sectoral implementation pathways, with special emphasis on differences between developed and developing countries and regional conditions, provide tools to implement the scenarios globally and domestically. Non-energy greenhouse gas mitigation scenarios define a sustainable pathway for land-use change and the agricultural sector. Furthermore, results of the impact of the scenarios on employment and mineral and resource requirements provide vital insight on economic and resource management implications. The book clearly demonstrates that the goals of the Paris Agreement are achievable and feasible with current technology and are beneficial in economic and employment terms. It is essential reading for anyone with responsibility for implementing renewable energy or climate targets internationally or domestically, including climate policy negotiators, policy-makers at all levels of government, businesses with renewable energy commitments, researchers and the renewable energy industry.
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Conference Paper
Pathways for achieving the 1.5-2 ºC target imply a massive scaling of CO2 removal technologies, in particular in the 2040s and onwards. CO2 direct air capture (DAC) is among the most promising negative emission technologies (NETs). The energy demands for low temperature, solid solution DAC are mainly heat at around 100 ºC and electricity, which lead to sustainably operated DAC systems based on low-cost renewable electricity and heat pumps for the heat supply. This analysis is carried out for the case of the Maghreb region, which enjoys abundantly available low-cost renewable energy resources. The energy transition results for the Maghreb region lead to a solar photovoltaic (PV) dominated energy supply with some wind energy contribution. DAC systems will need the same energy supply structure. The research investigates the levelised cost of CO2 DAC (LCOD) in high spatial resolution and is based on full hourly modelling for the Maghreb region. The key results are LCOD of about 55 €/tCO2 in 2050 with a further cost reduction potential of up to 50%. The area demand is considered and concluded to be negligible. Major conclusions for CO2 removal as a new energy sector are drawn.