Direct air capture (DAC) is considered one of the mitigation strategies in most of the future scenarios trying to limit global temperature to 1.5 °C. Given the high expectations placed on DAC for ...future decarbonisation, this study presents an extensive review of DAC technologies, exploring a number of techno-economic aspects, including an updated collection of the current and planned DAC projects around the world. A dedicated analysis focused on the production of synthetic methane, methanol, and diesel from DAC and electrolytic hydrogen in the European Union (EU) is also performed, where the carbon footprint is analysed for different scenarios and energy sources. The results show that the maximum grid carbon intensity to obtain negative emissions with DAC is estimated at 468 gCO2e/kWh, which is compliant with most of the EU countries’ current grid mix. Using only photovoltaics (PV) and wind, negative emissions of at least −0.81 tCO2e/tCO2 captured can be achieved. The maximum grid intensities allowing a reduction of the synthetic fuels carbon footprint compared with their fossil-fuels counterparts range between 96 and 151 gCO2e/kWh. However, to comply with the Renewable Energy Directive II (REDII) sustainability criteria to produce renewable fuels of non-biological origin, the maximum stays between 30.2 to 38.8 gCO2e/kWh. Only when using PV and wind is the EU average able to comply with the REDII threshold for all scenarios and fuels, with fuel emissions ranging from 19.3 to 25.8 gCO2e/MJ. These results highlight the importance of using renewable energies for the production of synthetic fuels compliant with the EU regulations that can help reduce emissions from difficult-to-decarbonise sectors.
The Unresolved Obstacles Source Term (UOST) is a general methodology for parameterizing the dissipative effects of subscale islands, cliffs, and other unresolved features in ocean wave models. Since ...it separates the dissipation from the energy advection scheme, it can be applied to any numerical scheme or any type of mesh. UOST is now part of the official release of WAVEWATCH III, and the freely available package
alphaBetaLab
automates the estimation of the parameters needed for the obstructed cells. In this contribution, an assessment of global regular and unstructured (triangular) wave models employing UOST is presented. The results in regular meshes show an improvement in model skill, both in terms of spectrum and of integrated parameters, thanks to the UOST modulation of the dissipation with wave direction, and to considering the cell geometry. The improvement is clear in wide areas characterized by the presence of islands, like the whole central-western Pacific Basin. In unstructured meshes, the use of UOST removes the need of high resolution in proximity of all small features, leading to (a) a simplification in the development process of large scale and global meshes, and (b) a significant decrease of the computational demand of accurate large-scale models.
Photovoltaics (PV) is a cost-competitive and scalable technology for electricity generation that plays a crucial role to accelerate the European energy transition and achieve carbon neutrality. ...Large-scale installation of rooftop PV, as well as innovative PV applications such as floating PV coupled with hydropower and bifacial PV along roads and railways, offer multi-benefits, not least in reducing competition for land. In this study, we present a geospatial approach to assess the pan-European technical potential of these three applications, using publicly available datasets. The findings reveal that the PV total installed capacity could exceed 1 TW
p
, which is far larger than the total PV capacity for 2030 in the EU Solar Energy Strategy (720 GW
p
) and would be a significant contribution to the several TWs needed for the overall transition to net-zero by 2050. The evidence presented is a useful starting point for policy-setting at national and regional level, as well as for research and detailed analyses of location specific solutions.
The Integrated system for Natural Capital Accounting (INCA) was developed and supported by the European Commission to test and implement the System of integrated Environmental and Economic Accounting ...– Ecosystem Accounting (SEEA EA). Through the compilation of nine Ecosystem Services (ES) accounts, INCA can make available to any interested ecosystem accountant a number of lessons learned. Amongst the conceptual lessons learned, we can mention: (i) for accounting purposes, ES should be clustered according to the existence (or not) of a sustainability threshold; (ii) the assessment of ES flow results from the interaction of an ES potential and an ES demand; (iii) the ES demand can be spatially identified, but for an overarching environmental target, this is not possible; ES potential and ES demand could mis-match; (iv) because the demand remains unsatisfied; (v) because the ES is used above its sustainability threshold or (vi) because part of the potential flow is missed; (vii) there can be a cause-and-effect relationship between ecosystem condition and ES flow; (viii) ES accounts can complement the SEEA Central Framework accounts without overlapping or double counting. Amongst the methodological lessons learned, we can mention: (ix) already exiting ES assessments do not directly provide ES accounts, but will likely need some additional processing; (x) ES cannot be defined by default as intermediate; (xi) the ES remaining within ecosystems cannot be reported as final; (xii) the assessment and accounting of ES can be undertaken throughout a fast track approach or more demanding modelling procedures.
The European Green Deal was published at the end of 2019 and represents EU's biggest action to reach climate neutrality. The European Recovery Fund was presented in July 2020 as a response to the ...COVID-19 crisis. This study looks at the role that photovoltaics could play to support the successful implementation of these initiatives, in particular in regard to the increased climate ambition. The European Commission proposal of September 2020 (55% emission reduction in 2030 compared to 1990) and the European Parliament proposal that followed soon after (−60%), have changed the level of greenhouse gas reduction ambitions. Energy system modelling shows that achieving the updated targets will require large quantities of renewables deployed at an unprecedented pace. Over the past 10 years solar PV has achieved the technological and market maturity to spearhead EU efforts to reach the energy and climate targets. The paper looks at future projections of solar PV deployment, also considering ongoing sectorial policies (e.g. the EU hydrogen strategy, the building renovation wave) and overarching aims for system integration and a just transition.
•The European Green Deal increased climate ambition and the need for renewables.•Photovoltaics need to be deployed in high rates to reach the updated targets.•Until 2030, 21–22 GW of PV is needed annually in EU to decrease emissions by 55%.•PV deployment rates increase to 26–32 GW annually to reach −60% emissions.•Green Deal's initiatives (H2 strategy, renovation wave) may increase projections.
This work provides a rare quantification of lateral spreading from Lagrangian measurements in a buoyant river plume by comparing four methods. Drifter motions, including along‐stream shear and ...rotation, can be incorrectly interpreted as lateral spreading. This work aims to improve estimates of lateral spreading by identifying additional motions in drifter trajectories. The techniques applied are first evaluated and compared using an idealized group of drifters undergoing specific types of motion, and then applied to in situ data from 27 surface Lagrangian drifters released in the Merrimack River plume (Massachusetts) under a variety of different environmental conditions. The techniques tested include two methods using the standard deviation of drifter position with respect to various interpretations of mean drifter direction and two methods using a rotating elliptical coordinate reference frame. The idealized trajectories are modeled analytically with each type of motion (i.e., spreading, rotation, and shear) separately, then in different combinations, to identify the method that best resolves and isolates lateral spreading. The idealized experiments demonstrate that three of the methods are sensitive to shear and rotational motion in various combinations. The most robust method resolving lateral spreading is the “time‐step” method, which applies a reference frame that follows the mean flow at each time step, calculated as the average direction of the drifters between two time steps. This method also successfully identifies lateral spreading in observations, which is maximized in classic bulge‐shaped plume deployments. This work is applicable to other river plume systems as well as other propagating oceanographic phenomena.
A potential response to the COVID-19 pandemic in sub-Saharan Africa (SSA) with long-term benefits is to provide electricity for medical equipment in rural health centers and communities. This study ...identifies a large gap in the electrification of healthcare facilities in SSA, and it shows that decentralized photovoltaic systems can offer a clean, reliable, quick, and cost-effective solution. The cost of providing renewable electricity to each health facility by a stand-alone PV system is analyzed for a given location (incorporating operational costs). The upfront investment cost for providing electricity with PV to >50,000 facilities (mostly primary health posts) currently without electricity is estimated at EUR 484 million. Analysis of the accessibility and population distribution shows that 281 million people could reduce their travel time to healthcare facilities (by an average of 50 min) if all facilities were electrified.
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•In rural sub-Saharan Africa, over 50,000 healthcare facilities lack electricity supply•PV and battery systems offer a clean, reliable, and cost-effective solution•The estimated investment needed would be just under EUR 500 million•281 million people could reduce journey time to electrified facilities by 50 min average
Our results shed new light on the potential of decentralized energy systems to offer a reliable, quick, and cost-effective way to increase access to electricity for rural healthcare facilities in sub-Saharan Africa. This study identified more than 55,000 such facilities without electricity access and analyzed the costs and benefits of powering each of these with solar photovoltaic and battery storage systems.
Our results can provide a basis for planning electrification programs for health facilities in rural sub-Saharan Africa and can be useful to policy makers, researchers, consultants, and other stakeholders involved in electrification planning and healthcare improvement. The level of granularity, covering community, national, and regional levels, is particularly relevant to prioritizing the allocation of limited governmental funding, highlighting where electrification is most needed and likely to have the greatest impact on health services.
Effective strategies for financing the electrification of healthcare remain a challenge in sub-Saharan Africa. In this study, Moner-Girona et al. identify a large gap in the electrification of healthcare facilities, and they show that decentralized photovoltaic systems can offer a clean, reliable, quick, and cost-effective solution. These findings provide a bottom-up geographic information system (GIS) framework for policy makers, researchers, consultants, and other stakeholders bridging two elements of the sustainable development goals: “energy for all” (SDG7) and “healthcare for all” (SDG3).
River plume source-front connectivity Cole, Kelly L.; MacDonald, Daniel G.; Kakoulaki, Georgia ...
Ocean modelling,
June 2020, 2020-06-00, Letnik:
150
Journal Article
Recenzirano
Odprti dostop
River plume source-front connectivity, or the relationship between processes at the source, plume body and front, is investigated with numerical simulations of the Merrimack River plume using the ...Regional Ocean modeling System (ROMS). Source water, i.e. water discharged from the estuary during an ebb pulse, overtakes the front as it propagates offshore, resulting in the strong convergence that exists there. Model results show that much of the water released over an ebb pulse does not interact with the propagating tidal plume front, suggesting that the front decouples from the source and sustains itself as a distinct water mass. When a gate is closed at the estuary mouth during early ebb, the overall plume structure changes; gates closed late in ebb do not significantly effect the along- or cross-shore scale of the plume. The change in plume extent is only evident hours after the early-ebb gate closing, when source water is no longer supplied to the front. These experiments suggest that the growing distance between the highly energetic liftoff region and the radial expansion of the plume front results in a flattening of the surface gradient driving flow in the interior, diminishing source-front connectivity.
•Much of the water released over an ebb does not interact with the propagating tidal plume front.•The plume front decouples from the source and sustains itself as a distinct water mass during ebb.•Distance between the mouth and front results in flattening of plume interior sea surface gradient, diminishing source-front connectivity.
•We present a novel method to account for flood control as ecosystem service.•Flood control includes different components: potential, demand and actual flow.•We provide an experimental account in ...line with up-to-date integrated accounting systems.•The estimated value of flood control at the EU level is about 16 billion euro.•Artificial areas not protected by ecosystems increased between 2006 and 2012.
Ecosystem service accounts require quantifying the contribution of ecosystems to the society. However, estimation of the ecosystem service used (actual flow) remains still very challenging for regulating services. We developed an experimental ecosystem service account for flood control delivered by ecosystems including: 1) Biophysical modelling of ecosystem service potential, demand and actual flow. 2) Translation of the actual flow in monetary terms. 3) Compilation of accounting tables. Ultimately, we analysed changes in flood control between 2006 and 2012.
The value of flood control delivered by ecosystems in 2012 is estimated at about 16 billion euro. This value increased by 1.14% between 2006 and 2012. This increase is mainly due to the sprawl of artificial areas into floodplains that benefit from flood control delivered by ecosystems. However, the role of natural capital to control floods is slightly decreasing. This is confirmed by the increase of artificial areas not protected by ecosystems (+1.9%, unmet demand). The role of natural capital to control floods could be enhanced by restoring ecosystems upstream from this unmet demand and increase the ecosystems contribution to human well-being. The methodology makes a significant contribution to the assessment of ecosystem services flow and the accounting framework.
Since the introduction of the first European Renewable Energy Directive in 2009, PV installations have significantly increased to reach over 139 GWp in the European Union (EU27) at the end of 2020. ...The European Green Deal, endorsed by the European Council in December 2020 sets new climate targets, bringing opportunities and challenges for the deployment of solar photovoltaic and renewable in general. The lessons learned during the last decade highlight the importance of legal and regulatory continuity to ensure investor confidence. It has also become clear that only solar PV and wind sources have the market potential to allow the EU to reach its strategic goals for the energy transition.
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