This contribution provides a conceptual analysis and a quantitative comparative assessment of three technology chains that enable a carbon neutral chemical industry in a net-zero-CO2 world. These are ...based (i) on the use of fossil fuels and current chemical processes and infrastructure coupled with carbon capture and storage (CCS route), (ii) on the use of captured CO2 as a feedstock together with “green” hydrogen in new chemical processes (CCU route), (iii) on the use of biomass grown and processed for the specific purpose of making chemicals (BIO route). All routes are feasible and have different pros and cons. Such pros and cons are first discussed through a qualitative comparison of the three routes for a generic chemical product, and are then quantitatively assessed for the specific case of methanol production. In this case, the CCU route results in an electricity consumption 10 to 25 times higher than that of the CCS and BIO routes (excluding the electricity required for heat production), mostly due to the electricity required to produce hydrogen. At the same time, the BIO route requires a land capacity about 40 and 400 times higher than that required by the CCU and CCS routes, respectively. Furthermore, when considering a net-positive-CO2 emissions world, the CO2 emissions of the CCU route grow about 8 to 10 times faster than that of the CCS and BIO routes. On the one hand, we identify key hurdles in all cases. These are (i) the availability, accessibility, and acceptance of CO2 storage sites for the CCS route, together with the continued use of fossil fuels; (ii) the very high electricity and energy demand for the CCU route, with the associated strict requirement of very low carbon-intensity of the electricity mix; (iii) the very high availability of land for biomass growth in the case of the BIO route, with the associated risks of conflict with other uses. On the other hand, we underline that the CCS route offers the possibility of using existing technologies and infrastructures, without the need of a complete reshaping of the chemical industry, and of permanently removing CO2 from the atmosphere, hence representing a key element not only in the net-zero-CO2 emissions world studied here, but also in a net-negative-CO2 emissions world.
Abstract
By synthetically producing nitrogen fertilizers from ammonia (NH
3
), the Haber–Bosch process has been feeding humanity for more than one hundred years. However, current NH
3
production ...relies on fossil fuels, and is energy and carbon intensive. This commits humanity to emissions levels not compatible with climate goals and commits agricultural production to fossil fuels dependency. Here, we quantify food and energy implications of transitioning nitrogen fertilizers to net-zero CO
2
emissions. We find that 1.07 billion people are fed from food produced from imported nitrogen fertilizers. An additional 710 million people are fed from imported natural gas feedstocks used for fertilizers production, meaning that 1.78 billion people per year are fed from imports of either fertilizers or natural gas. These findings highlight the reliance of global food production on trading and fossil fuels, hence its vulnerability to supply and energy shocks. However, alternative routes to achieve net-zero emissions in NH
3
production exist, which are based on carbon capture and storage, electrification, and biomass. These routes comply with climate targets while mitigating the risks associated with food security. Yet, they require more land, energy, and water than business-as-usual production, exacerbating land and water scarcity and the use of limited natural resources. Transitioning fertilizers to net-zero emissions can contribute to climate and food security goals, although water, land, and energy trade-offs should be considered.
Abstract
Agriculture accounts for 12% of global annual greenhouse gas (GHG) emissions (7.1 Gt CO
2
equivalent), primarily through non-CO
2
emissions, namely methane (54%), nitrous oxide (28%), and ...carbon dioxide (18%). Thus, agriculture contributes significantly to climate change and is significantly impacted by its consequences. Here, we present a review of technologies and innovations for reducing GHG emissions in agriculture. These include decarbonizing on-farm energy use, adopting nitrogen fertilizers management technologies, alternative rice cultivation methods, and feeding and breeding technologies for reducing enteric methane. Combined, all these measures can reduce agricultural GHG emissions by up to 45%. However, residual emissions of 3.8 Gt CO
2
equivalent per year will require offsets from carbon dioxide removal technologies to make agriculture net-zero. Bioenergy with carbon capture and storage and enhanced rock weathering are particularly promising techniques, as they can be implemented within agriculture and result in permanent carbon sequestration. While net-zero technologies are technically available, they come with a price premium over the status quo and have limited adoption. Further research and development are needed to make such technologies more affordable and scalable and understand their synergies and wider socio-environmental impacts. With support and incentives, agriculture can transition from a significant emitter to a carbon sink. This study may serve as a blueprint to identify areas where further research and investments are needed to support and accelerate a transition to net-zero emissions agriculture.
Abstract
Proposals for achieving net-zero emissions by 2050 include scaling-up electrolytic hydrogen production, however, this poses technical, economic, and environmental challenges. One such ...challenge is for policymakers to ensure a sustainable future for the environment including freshwater and land resources while facilitating low-carbon hydrogen production using renewable wind and solar energy. We establish a country-by-country reference scenario for hydrogen demand in 2050 and compare it with land and water availability. Our analysis highlights countries that will be constrained by domestic natural resources to achieve electrolytic hydrogen self-sufficiency in a net-zero target. Depending on land allocation for the installation of solar panels or wind turbines, less than 50% of hydrogen demand in 2050 could be met through a local production without land or water scarcity. Our findings identify potential importers and exporters of hydrogen or, conversely, exporters or importers of industries that would rely on electrolytic hydrogen. The abundance of land and water resources in Southern and Central-East Africa, West Africa, South America, Canada, and Australia make these countries potential leaders in hydrogen export.
How to make climate-neutral aviation fly Sacchi, Romain; Becattini, Viola; Gabrielli, Paolo ...
Nature communications,
07/2023, Letnik:
14, Številka:
1
Journal Article
Recenzirano
Odprti dostop
The European aviation sector must substantially reduce climate impacts to reach net-zero goals. This reduction, however, must not be limited to flight CO
emissions since such a narrow focus leaves up ...to 80% of climate impacts unaccounted for. Based on rigorous life-cycle assessment and a time-dependent quantification of non-CO
climate impacts, here we show that, from a technological standpoint, using electricity-based synthetic jet fuels and compensating climate impacts via direct air carbon capture and storage (DACCS) can enable climate-neutral aviation. However, with a continuous increase in air traffic, synthetic jet fuel produced with electricity from renewables would exert excessive pressure on economic and natural resources. Alternatively, compensating climate impacts of fossil jet fuel via DACCS would require massive CO
storage volumes and prolong dependence on fossil fuels. Here, we demonstrate that a European climate-neutral aviation will fly if air traffic is reduced to limit the scale of the climate impacts to mitigate.
This work aims at giving an updated picture of the strict interaction between main plant biologically active compounds and botanicals. The main features of the emerging class of dietary supplements, ...the botanicals, are highlighted. Focus is also on the definition of actual possibilities of study approach and research strategies. Examples of innovative directions are given: assessment of interaction of bioactive compounds, chemometrics and the new goal of biorefineries. Current models of existing databases, such as plant metabolic pathways, food composition, bioactive compounds, dietary supplements, and dietary markers, are described as usable tools for health research. The need for categorization of botanicals as well as for the implementation of specific and dedicated databases emerged, based on both analytical data and collected data taken from literature throughout a harmonized and standardized approach for the evaluation of an adequate dietary intake.
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•Multi-objective optimization of multi-energy systems for costs and CO2 emissions.•Definition of conditions that enable deployment of Power-to-Hydrogen.•Stochastic input data based on ...a comprehensive pan-European literature review.•Uncertainty analysis considering district conditions and techno-economic parameters.•Importance of capturing optimal short- and long-term energy storage strategies.
This study analyzes the factors leading to the deployment of Power-to-Hydrogen (PtH2) within the optimal design of district-scale Multi-Energy Systems (MES). To this end, we utilize an optimization framework based on a mixed integer linear program that selects, sizes, and operates technologies in the MES to satisfy electric and thermal demands, while minimizing annual costs and CO2 emissions. We conduct a comprehensive uncertainty analysis that encompasses the entire set of technology (e.g. cost, efficiency, lifetime) and context (e.g. economic, policy, grid carbon footprint) input parameters, as well as various climate-referenced districts (e.g. environmental data and energy demands) at a European-scope.
Minimum-emissions MES, with large amounts of renewable energy generation and high ratios of seasonal thermal-to-electrical demand, optimally achieve zero operational CO2 emissions by utilizing PtH2 seasonally to offset the long-term mismatch between renewable generation and energy demand. PtH2 is only used to abate the last 5–10% emissions, and it is installed along with a large battery capacity to maximize renewable self-consumption and completely electrify thermal demand with heat pumps and fuel cells. However, this incurs additional cost. Additionally, we show that ‘traditional’ MES comprised of renewables and short-term energy storage are able to decrease emissions by 90% with manageable cost increases.
The impact of uncertainty on the optimal system design reveals that the most influential parameter for PtH2 implementation is (1) heat pump efficiency as it is the main competitor in providing renewable-powered heat in winter. Further, battery (2) capital cost and (3) lifetime prove to be significant as the competing electrical energy storage technology. In the face of policy uncertainties, a CO2 tax shows large potential to reduce emissions in district MES without cost implications. The results illustrate the importance of capturing the dynamics and uncertainties of short- and long-term energy storage technologies for assessing cost and CO2 emissions in optimal MES designs over districts with different geographical scopes.
•Spatiotemporal MILP optimization of an energy system supplying electricity and H2.•Novel approach to model large wind turbine portfolios using a clustering algorithm.•With increasing H2 demand, the ...share of H2 converted back to electricity decreases.•Cost of H2 increases with demand as a result of increasing system expansion cost.•Competitive advantage of PtH2 over batteries depends on operation flexibility.
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The role of hydrogen in future energy systems is widely acknowledged: from fuel for difficult-to-decarbonize applications, to feedstock for chemicals synthesis, to energy storage for high penetration of undispatchable renewable electricity. While several literature studies investigate such energy systems, the details of how electrolysers and renewable technologies optimally behave and interact remain an open question. With this work, we study the interplay between (i) renewable electricity generation through wind and solar, (ii) electricity storage in batteries, (iii) electricity storage via Power-to-H2, and (iv) hydrogen commodity demand. We do so by designing a cost-optimal zero-emission energy system and use the Netherlands as a case study in a mixed integer linear model with hourly resolution for a time horizon of one year. To account for the significant role of wind, we also provide an elaborate approach to model broad portfolios of wind turbines. The results show that if electrolyzers can operate flexibly, batteries and power-to-H2-to-power are complementary, with the latter using renewable power peaks and the former using lower renewable power outputs. If the operating modes of the power-to-H2-to-power system are limited - artificially or technically - the competitive advantage over batteries decreases. The preference of electrolyzers for power peaks also leads to an increase in renewable energy utilization for increased levels of operation flexibility, highlighting the importance of capturing this feature both from a technical and a modeling perspective. When adding a commodity hydrogen demand, the amount of hydrogen converted to electricity decreases, hence decreasing its role as electricity storage medium.
The study aims to communicate the current status regarding the development and management of the databases on dietary lignans; within the phytochemicals, the class of the lignan compounds is of ...increasing interest because of their potential beneficial properties, i.e., anticancerogenic, antioxidant, estrogenic, and antiestrogenic activities. Furthermore, an introductory overview of the main characteristics of the lignans is described here. In addition to the importance of the general databases, the role and function of a food composition database is explained. The occurrence of lignans in food groups is described; the initial construction of the first lignan databases and their inclusion in harmonized databases at national and/or European level is presented. In this context, some examples of utilization of specific databases to evaluate the intake of lignans are reported and described.
Chlorophyll pigments are thought to be responsible for the highly appreciated green color of unfermented Castelvetrano-style table olives, but no studies have considered the effects of a controlled ...addition of copper during storage or packaging at the industrial level. For this purpose, chlorophyll derivatives were analyzed in Nocellara cultivar table olives debittered industrially using the Castelvetrano method, via means of HPLC and MS analyses, following the addition of copper in alkaline brines stored at 4 °C for 3 months in 220 L barrels, and during the subsequent storage in acid brines in commercial 400 g packages at 4 °C for up to 18 months. The presence of copper in storage or in packaging brines both contributed significantly to maintaining the green color of the olives, which was associated with a specific pattern of chlorophyll derivatives, as evidenced by principal component analysis. Notably, re-greening was rapidly achievable also for olives that had yellowed for 18 months at a copper concentration below the limit of EU legislation. Finally, by means of PCA, we also demonstrated that a short-term thermic treatment can work as an accelerated predictive tool in determining the fate of chlorophyll derivatives.
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