A Circular Approach for Making Fischer–Tropsch E-fuels and E-chemicals From Biogas Plants in Europe

In a mature circular economy model of carbon material, no fossil compound is extracted from the underground. Hence, the C1 molecule from non-fossil sources such as biogas, biomass, or carbon dioxide captured from the air represents the raw material to produce various value-added products through carbon capture and utilization routes. Accordingly, the present work investigates the utilization of the full potential of biogas and digestate waste streams derived from anaerobic digestion processes available at the European level to generate synthetic Fischer–Tropsch products focusing on the wax fraction. This study estimates a total amount of available carbon dioxide of 33.9 MtCO2/y from the two above-mentioned sources. Of this potential, 10.95 MtCO2/y is ready-to-use as separated CO2 from operating biogas-upgrading plants. Similarly, the total amount of ready-to-use wet digestate corresponds to 29.1 Mtdig/y. Moreover, the potential out-take of Fischer–Tropsch feedstock was evaluated based on process model results. Utilizing the full biogas plants’ carbon potential available in Europe, a total of 10.1 Mt/h of Fischer–Tropsch fuels and 3.86 Mt/h of Fischer–Tropsch waxes can be produced, covering up to 79% of the global wax demand. Utilizing only the streams derived from biomethane plants (installed in Europe), 136 ton/h of FT liquids and 48 ton/h of FT wax can be generated, corresponding to about 8% of the global wax demand. Finally, optimal locations for cost-effective Fischer–Tropsch wax production were also identified

Solar-Powered Rankine Cycle Assisted by an Innovative Calcium Looping Process as an Energy Storage System

Solar energy is an intermittent resource, and thus an energy storage system is required for practical applications of the collected solar irradiance. This work deals with the integration of a thermo-chemical energy storage (TCES) system based on the calcium looping (CaL) process with a concentrated solar tower power (CSP) plant. The objective of this work is the integration of a conventional 320 MWe Rankine cycle with a direct calcination for energy harvesting. Particularly, this work addresses the use of CO2 as the working fluid of a compressed-gas energy storage (CGES) system for hybrid energy storage with the CaL process. The hybrid TC/CG-ES (thermo-chemical/compressed-gas energy storage) system can increase the competitiveness of the CSP with respect to conventional fossil-based power plants leading to a reduction in CO2 emissions. The thermal integration with the calcium looping (CaL) system is optimized by means of the pinch analysis methodology. The obtained results show a reduction in the electrical efficiency of about four percentage points with respect to the conventional Rankine power cycle without the CSP unit: the net electrical efficiency reduces from 43.7% to 39.5% while the global (thermal and electrical) efficiency of the plant reaches the peak value of 51.5% when low enthalpy energy is recovered (e.g., district heating network, district cooling network). This paper highlights the importance of the thermochemical CaO based material. With a conversion of CaO to CaCO3 of 80% the storage efficiency is defined as the ratio of the energy released during the carbonation and the CO2 expansion to the energy collected by the solar field and required during the CO2 compression, which is 87.3%

Atomic ordering in cu-al-mn studied by the Monte Carlo method

En este trabajo se estudian los procesos de ordenamiento atómico en la fase bcc del sistema ternario Cu-Al-Mn por medio de simulaciones de Monte Carlo. Se han utilizado dos enfoques diferentes: en primera instancia, se consideró que el ordenamiento atómico ocurre a causa de interacciones puramente químicas entre las tres especies atómicas. Posteriormente, se consideraron también interacciones de carácter magnético entre los átomos de Mn, y se analizó el modo en que éstas modifican las temperaturas de orden-desorden. Se muestra que, con una adecuada elección de los parámetros energéticos, el método reproduce las temperaturas de transición de orden de largo alcance determinadas experimentalmente en un amplio rango de composiciones.In this paper, the atomic ordering processes in the bcc phase of the Cu-Al-Mn ternary system are studied by means of Monte Carlo simulations. Two different approaches were used: first, it was assumed that the atomic ordering is caused by purely chemical interactions between the three atomic species. Later, magnetic interactions between Mn atoms were also taken into account, and its influence on order-disorder temperatures was analyzed. It is shown that, provided an appropriate choice of the energetic parameters, the method reproduces the experimentally determined long-range order transition temperatures over a wide range of compositions.Fil: Alés, A.. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Fisica de Materiales; Argentina;Fil: Lanzini, Fernando Gabriel. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Fisica de Materiales; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina;Fil: Romero, R.. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina; Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Fisica de Materiales; Argentina

Compact model of latent heat thermal storage for its integration in multi-energy systems

Nowadays, flexibility through energy storage constitutes a key feature for the optimal management of energy systems. Concerning thermal energy, Latent Heat Thermal Storage (LHTS) units are characterized by a significantly higher energy density with respect to sensible storage systems. For this reason, they represent an interesting solution where limited space is available. Nevertheless, their market development is limited by engineering issues and, most importantly, by scarce knowledge about LHTS integration in existing energy systems. This study presents a new modeling approach to quickly characterize the dynamic behavior of an LHTS unit. The thermal power released or absorbed by a LHTS module is expressed only as a function of the current and the initial state of charge. The proposed model allows simulating even partial charge and discharge processes. Results are fairly accurate when compared to a 2D finite volume model, although the computational effort is considerably lower. Summarizing, the proposed model could be used to investigate optimal LHTS control strategies at the system level. In this paper, two relevant case studies are presented: (a) the reduction of the morning thermal power peak in District Heating systems; and (b) the optimal energy supply schedule in multi-energy systems

Digital Platforms for Renewable Energy Communities Projects: An Overview

The European Union energy policy agenda of achieving the transition to carbon neutrality has been established by an important legislative package called "Clean Energy for all Europeans". A novel approach introduced was to put the citizen at the center of the energy transition. On one side, by powering his freedom of action and, on the other side, by asking him an exceptional engagement in energy consumption reduction activities and in participating in the investments for new distributed Renewable Energy Sources (RES) power plants. The Renewable Energy Communities (REC) is the policy framework used to implement this strategy introduced by the Renewable Energy Directive Recast (RED II). In particular, RECs promote citizen’s active role by encouraging energy consumption reduction and energy demand flexibility while reducing the Not In My Bachyard (NIMBY) effect towards RES. Each member state is transposing the RED II directive, adapting it to national legislation and energy transition strategy. Pioneers countries like Italy have already started the experimentation of this framework and developing the first pilot projects. The citizens’ interest and their will to participate in REC projects indicate the need for supporting tools guiding them along all the project development stages: “design”, “creation”, and “operation”. This work presents three categories of supporting digital tools and platforms required to develop REC projects: Commercial, EU Founded and Freeware. We analyzed 30 tools, evaluating the services provided in each of the different stages of REC project implementation

Green synthetic fuels: Renewable routes for the conversion of non-fossil feedstocks into gaseous fuels and their end uses

Innovative renewable routes are potentially able to sustain the transition to a decarbonized energy economy. Green synthetic fuels, including hydrogen and natural gas, are considered viable alternatives to fossil fuels. Indeed, they play a fundamental role in those sectors that are di cult to electrify (e.g., road mobility or high-heat industrial processes), are capable of mitigating problems related to flexibility and instantaneous balance of the electric grid, are suitable for large-size and long-term storage and can be transported through the gas network. This article is an overview of the overall supply chain, including production, transport, storage and end uses. Available fuel conversion technologies use renewable energy for the catalytic conversion of non-fossil feedstocks into hydrogen and syngas. We will show how relevant technologies involve thermochemical, electrochemical and photochemical processes. The syngas quality can be improved by catalytic CO and CO2 methanation reactions for the generation of synthetic natural gas. Finally, the produced gaseous fuels could follow several pathways for transport and lead to different final uses. Therefore, storage alternatives and gas interchangeability requirements for the safe injection of green fuels in the natural gas network and fuel cells are outlined. Nevertheless, the effects of gas quality on combustion emissions and safety are considered

Techno-economic assessment of biogas-fed CHP hybrid systems in a real wastewater treatment plant

The integration of solid oxide fuel cell (SOFC) systems and micro gas turbines in a reference wastewater treatment plant is proposed. The main scope is to utilize the available biogas in a real wastewater treat- ment plant (WWTP) to feed both the SOFCs and micro gas turbines (MGTs) to produce electrical power while covering the digester thermal demand of the plant. To do so, two cases namely SOFC-WWTP (in which the SOFC system is the only CHP unit), and SOFC-MGT-WWTP (integration of both SOFCs and microturbine systems) are proposed. Results show that use of microturbines along with the SOFC systems can increase the share of electricity covered by self-generation within the WWTP by up to 15% while keeping stable the coverage of the thermal load. Also, the energy efficiency of the novel system (SOFC- MGT-WWTP) is calculated to be 7% more than that of the SOFC-WWTP. Economic analysis results reveal that using microturbines, the payback time for whole the system could be reduced about 4 years. Also, for the short term scenario, the levelized cost of electricity for the SOFC-MGT-WWTP system is found to be 0.118 $/kWh which is about 12% less than that for the SOFC-WWTP system. However, for the long term scenario, the difference becomes remarkably les

Techno-economic comparison of buildings acting as Single-Self Consumers or as energy community through multiple economic scenarios

The European Union has set ambitious targets to move towards a society with high penetration of renewable energy sources. In the forthcoming energy transition, Energy Communities (EC), i.e., legal entities where different actors, including citizens, cooperate in energy generation, storage and management, will play a crucial role. The present work simulates the energy flows and assesses the potential economic benefits of a cluster of buildings acting collectively as an energy community – a specific case study is set in northern Italy by comparing the EC performance with a configuration where customers act as Single Self-Consumers (SSCs). Pending the transposition of EU Directives to binding national laws, due by 2021, different supporting tariffs (economic scenarios) have been simulated in order to determine which scheme will support more effectively the integration of Energy Communities in the national energy market. Results show that ECs (i.e., customers acting collectively as energy prosumers) are able to accelerate the diffusion of building-integrated renewable energy sources (RES), resulting in higher overall self-consumption rates than SSCs. Self-consumed electricity generates savings on the energy bill of EC, and we calculated positive economic performance indicators for all the analysed economic scenarios. The sensitivity analysis carried out on system and transport charges of the electricity bill shows their remarkable impact on the economics making the EC less attractive for investors and citizens without proper supporting schemes