Accounting for Mineral Depletion Under the UN-SEEA Framework

The scarcity factor of non-renewable resources is absent in conventional accounting methodologies. This chapter proposes an approach for accounting for abiotic resource depletion through the second law of thermodynamics. It is postulated that each chemical element has associated a cycle that should be closed either naturally or technologically. Once a mineral is extracted from the Earth, the cycle starts. The overall process from mining to dissipation is the cradle-to-grave path and is generally well characterized and accounted. However, to close the cycle, we need to account for an imaginary path through the “grave-to-cradle” approach. This semi-circle is a debt we acquire with future generations. It represents the effort that we should invest in returning minerals from a dispersed state to the initial conditions found in nature, and hence, it is a measure of depletion. This is calculated through exergy replacement costs, which indicate the energy effort required to close the cycle from the grave with prevailing technologies. The grave is the model of degraded Earth (called “Thanatia”), which was developed previously. This chapter concludes proposing the inclusion of this approach in the System of Environmental-Economic Accounts (SEEA), converting it into a “Global System of Environmental-Thermo-Economic Accounts” (SETEA)

Thermodynamic Rarity and Recyclability of Raw Materials in the Energy Transition: The Need for an In-Spiral Economy

This paper presents a thermodynamic vision of the depletion of mineral resources. It demonstrates how raw materials can be better assessed using exergy, based on thermodynamic rarity, which considers scarcity in the crust and energy requirements for extracting and refining minerals. An exergy analysis of the energy transition reveals that, to approach a decarbonized economy by 2050, mineral exergy must be greater than that of fossil fuels, nuclear energy, and even all renewables. This is because clean technologies require huge amounts of many different raw materials. The rapid exhaustion of mines necessitates an increase in recycling and reuse, that is, a “circular economy”. As seen in the automobile industry, society is far removed from closing even the first cycle, and absolute circularity does not exist. The Second Law dictates that, in each cycle, some quantity and quality of materials is unavoidably lost (there are no circles, but spirals). For a rigorous recyclability analysis, we elaborate the exergy indicators to be used in the assessment of the true circularity of recycling processes. We aim to strive toward an advanced economy focused on separating techniques and promoting circularity audits, an economy that inspires new solutions: an in-spiral economy

Energy and carbon footprint of metals through physical allocation. Implications for energy transition

The increasing metal demand driven by energy and digital transition has led to more complex mining operations. To allocate environmental impacts in cases of mining co-production, this study proposes a physical method based on the relative geological scarcity of elements, which provides the basis for an exergy cost allocation. It focuses on calculating the energy and carbon footprint of 51 metals, including 28 co-products, based on available databases. The analysis considers the fuel type, main production stages and the energy footprint of up to 25 chemicals. This study provides new insights into 39 infrequently studied metals. Results show that by using renewable electricity in production, 41 metals can reduce their carbon footprint by up to 50 %. However, key metals such as Fe or Li require additional decarbonization efforts beyond electricity. Only by decarbonizing metal production is possible a renewable infrastructure that can achieve the energy transition goals

Stock in use in the urban mobility system. An exergy approach

Around 75% of European population lives in urban and metropolitan areas[1], causing not only a size increase of cities but also a mobility demand growth. Nowadays 2,7 daily trips per person are made[2] and the consequence of this effect can be shown in the 7% increase of the passenger-kilometer indicator since last decade[3]. Moreover, 49% of urban daily trips are made using private vehicles with the negative associated impact[4]. Some of the most known problem are: Traffic jams, which costs are estimated in 80.000 M€/year[5]; GHG emissions, where urban mobility generate 23% of CO2 emissions or traffic accidents, where urban mobility is responsible for 38% of fatal urban traffic collisions[6]. Nevertheless there is a critical impact not yet taken into account which needs to be equally assessed, namely the natural resources availability to guarantee a sustainable supply of the raw materials required to manufacture transport systems and their associated infrastructures. Indeed, only in the EU motorization rates have grown up to 11,7 %[7] from 2005 to 2013 and the vehicle average age has also increased to an average of 9,65 years[8]. These figures show the large amount of cars that will be demanded in the near future. Besides, conventional fuel vehicles will likely soon be replaced by “eco-friendlier” ones, consuming less or even not oil at all. Accordingly, alternative fuel vehicles such as Hybrid Electric Vehicles (HEV) or Electrical Vehicles (EV) will play a key role, as corroborated by the 62,2% and 34,7% sales increase in the third quarter of 2015, respectively. Yet even if such vehicles seem to be more respectful with the environment, they contain a very important amount of critical raw materials such as rare earths that may put at risk the electrification of the vehicle sector. In this paper a new assessment methodology based on exergy analysis to quantify the impact of different types of vehicles is presented and compared with conventional LCA approaches. The assessment methodology uses the so called exergy replacement cost (ERC) indicator to assess the criticality of the materials used. The ERC represents the useful energy that would be needed to return minerals from the most dispersed state (the bedrock) to their original conditions (of composition and concentration in the mineral deposits). Dispersing a scarce and critical mineral such as platinum or neodymium has a much higher replacement cost than that of iron for instance, and in the final accounting the first minerals have a greater weighting, even if the quantities used to manufacture vehicles are much lower. By means of this approach the exergy contained in the stock in use of urban mobility systems is assessed. This information is very valuable for automobile manufacturers and urban planners to guarantee the future adoption of really urban mobility sustainable policies. [1] http://www.eea.europa.eu/themes/urban [2] http://www.emta.com/IMG/pdf/barometer2013-150326.pdf [3]http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=SEC:2011:0358:FIN:EN:PDF [4] http://www.emta.com/IMG/pdf/barometer_report_2012_data_2009_.pdf [5] SEC (2011) 358 [6] http://eur-lex.europa.eu/resource.html?uri=cellar:82155e82-67ca-11e3-a7e4-01aa75ed71a1.0011.02/DOC_3&format=PDF. Brussels 17.12.2013. [7] http://www.acea.be/statistics/tag/category/passenger-car-fleet-per-capita [8]http://www.acea.be/statistics/tag/category/average-vehicle-ag

Thermodynamic Rarity Assessment of Mobile Phone PCBs: A Physical Criticality Indicator in Times of Shortage

Rising prices in energy, raw materials, and shortages of critical raw materials (CRMs) for renewable energies or electric vehicles are jeopardizing the transition to a low-carbon economy. Therefore, managing scarce resources must be a priority for governments. To that end, appropriate indicators that can identify the criticality of raw materials and products is key. Thermodynamic rarity (TR) is an exergy-based indicator that measures the scarcity of elements in the earth''s crust and the energy intensity to extract and refine them. This paper uses TR to study 70 Mobile Phone (MP) Printed Circuit Boards (PCBs) samples. Results show that an average MP PCB has a TR of 88 MJ per unit, indicating their intensive use of valuable materials. Every year the embedded TR in-creases by 36, 250 GWh worldwide-similar to the electricity consumed by Denmark in 2019-due to annual production of MP. Pd, Ta and Au embedded in MP PCBs worldwide between 2007 and 2021 contribute to 90% of the overall TR, which account for 75, 600 and 250 tones, respectively, and in-creasing by 11% annually. This, coupled with the short lifespan of MP, makes PCBs an important potential source of secondary resources. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Performance Evaluation of cuDNN Convolution Algorithms on NVIDIA Volta GPUs

Convolutional neural networks (CNNs) have recently attracted considerable attention due to their outstanding accuracy in applications, such as image recognition and natural language processing. While one advantage of the CNNs over other types of neural networks is their reduced computational cost, faster execution is still desired for both training and inference. Since convolution operations pose most of the execution time, multiple algorithms were and are being developed with the aim of accelerating this type of operations. However, due to the wide range of convolution parameter configurations used in the CNNs and the possible data type representations, it is not straightforward to assess in advance which of the available algorithms will be the best performing in each particular case. In this paper, we present a performance evaluation of the convolution algorithms provided by the cuDNN, the library used by most deep learning frameworks for their GPU operations. In our analysis, we leverage the convolution parameter configurations from widely used the CNNs and discuss which algorithms are better suited depending on the convolution parameters for both 32 and 16-bit floating-point (FP) data representations. Our results show that the filter size and the number of inputs are the most significant parameters when selecting a GPU convolution algorithm for 32-bit FP data. For 16-bit FP, leveraging specialized arithmetic units (NVIDIA Tensor Cores) is key to obtain the best performance.This work was supported by the European Union's Horizon 2020 Research and Innovation Program under the Marie Sklodowska-Curie under Grant 749516, and in part by the Spanish Juan de la Cierva under Grant IJCI-2017-33511Peer ReviewedPostprint (published version

Territorial inequalities, ecological and material footprints of the energy transition: case study of the Cantabrian-Mediterranean Bioregion

This study develops a methodology to assess the energy transition’s territorial, ecological and material impacts on regions. As a case study, the methodology is applied to the Cantabrian-Mediterranean Bioregion, a geographical area constituting eight autonomous communities located in the north of Spain. Two energy demand scenarios for 2030 and 2050 were assessed. The 2030 scenario is based on the Spanish government’s planning, and the 2050 scenario constitutes a net-zero emission economy based on electrification. Energy dependence between autonomous communities, energy and raw material needs, and availability are obtained for both scenarios. Results show a high imbalance between energy producer–consumer autonomous communities and an ecological and critical material deficit for the Bioregion. Two alternative scenarios are proposed, one based on self-sufficiency to ensure a balanced energy transition and another based on energy and material efficiency seeking that the ecological and critical material footprints do not surpass the planet’s carrying capacity. The indicators and methodology proposed can be easily replicated elsewhere and help develop more equitable and sustainable territorial planning strategies