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PV technologies are regarded as one of the most promising renewable options for the transition towards Net Zero. Despite the rapid development of PV systems in recent years, achieving the necessary goals requires more than a threefold increase in annual capacity deployment by 2030. However, current PV systems often fall short of optimal performance due to improper installation angles. In high-latitude cold regions, the actual PV generation capacity is frequently overestimated due to the omission of snow conditions. This study introduces a novel model designed for high-latitude regions to predict local optimal PV installation angle that maximizes PV power generation, utilizing historical weather big data, including snowfall and melting effects. A case study is presented within a Swedish context to demonstrate the implementation of these methods. The results highlight the crucial role snow conditions play in determining PV performance, resulting in an average reduction of 14.7% in annual PV power generation. Optimal installation angle could yield approximately a 4.8% improvement compared to common installation angles. The study also explores the application of snow removal agents, which could potentially increase PV generation by 0.1–2.3%. Additionally, the new PV installation angle successfully captures the impact of the local weather changes on PV power generation, potentially serving as a bridge between climate change adaptation and future PV power generation endeavors., QC 20240229

The transition towards sustainability necessitates robust growth of renewable energy, especially solar power. However, increasing the shares of solar power may lead to mismatch of electricity supply and demand, thus worse solar power performance could be received due to lower self-consumption and self-sufficiency. This issue has attracted more attention recently as it also requires additional costs for controlling and battery integration. This study combines several load profiles from consumers having different behaviors with different proportions to find out the optimal shares with higher level of PV penetration and self-sufficiency. A visualizing matching layout is proposed to present the PV-load matching level of all the possibilities at different seasons based on a Swedish context. It is found an 8% improvement of self-sufficiency reaching 70% in summer without additional equipment and scarification of self-consumption. The results could assist in the design and planning of the future power sector. Regarding specific targets, various optimal solutions could be found based on the layout., QC 20240919

In response to the ongoing climate crisis, the European Union has introduced a legislative package aimed at promoting clean energy initiatives. In this context, energy communities (E C s) are defined as core actors in the energy transition plan, by promoting local electricity generation, consumption, and sharing. This study aims to investigate the feasibility of E C s in Sweden, by performing a case study on a real distribution system in a Stockholm district. Solar photovoltaic (P V) and energy storage (E S) technologies are modeled and implemented into the system, and different scenarios are tested to identify optimal techno-economic solutions. The results indicate that self-consumption can increase up to 95%, and annual electricity costs are reduced by up to 30% compared to a case without PV generation. The analysis of the net present value (NPV) shows that collective self-consumption through shared solar applications increases the profitability of investing in PV by more than 24%., Part of ISBN: 979-835039678-2QC 20240301

The present work performs a thermodynamic analysis of a hybrid CSP – PV plant characterized by a particle tower CSP running a supercritical CO2 power unit and a PV field. The two plants are hybridized by employing a particle electrical heater that allows to store the electricity produced in excess by the PV field as thermal energy in the CSP storage. The PV production is compensated by the CSP plant to achieve the maximum power that can be injected into the grid (25 MW). The main key performance indicators considered in this analysis are the capacity factor, the share of energy wasted, the annual energy yield, the electric heater utilization factor, and the share of TES charged by the electric heater. The influence of the plant solar multiple, storage size, PV nominal size, electric heater efficiency, and electric heater capacity has been assessed through different sensitivity analyses. The results show that it is worth hybridizing the system, indeed the solar power plant operates during summer continuously day and night, exploiting the advantages of the two technologies, while limiting their drawbacks. Plant configurations leading to a capacity factor higher than 81% with a share of energy wasted limited to 5% can be identified. The electric heater capacity and efficiency are shown to be highly important parameters, highlighting the need for further component development., QC 20231206

Spectral hemispherical emissivity is a crucial material characteristic that determines radiation heat transfer. In high-temperature solar thermal applications, it affects not only the efficiency of the solar energy absorption but also the heat losses caused by thermal radiation and the radiative heat transfer within the receiver. Due to the limitations of the working temperature of existing solar absorber coatings, the spectral hemispherical emissivity of the oxidized surface is a key performance indicator for evaluating the potential of a candidate refractory alloy for high-temperature (> 1000 degrees C) solar receiver/reactor designs. In this work, we systematically studied the photothermal performances of the oxidized surfaces of three widely used high-performance commercial chromia-forming alloys (Haynes 230, Hastelloy X, and SS 253MA) by analyzing the spectral hemispherical reflectance in the band 0.25-25 mu m. The stability of the optical properties of the formed oxide layers have also been studied by exposing the three alloys at 1150 degrees C in air for three different exposure periods (10 h, 100 h, and 200 h). The results show that the solar absorptivity of all the samples is in the range of 0.800-0.855, with SS 253MA showing the best performances in offering both high and stable solar absorptivity in the range of 0.837-0.855. The evaluation of the photothermal performances suggest the potential of these three alloys in solar-thermal applications., QC 20230403

This work explores the state of digitalization of the European electricity sector and assesses the impacts of digital technologies on the electricity system and its main stakeholders. Digital technologies, such as smart meters and 5G connectivity, represent a powerful tool for system operators to face the new challenges brought about by the decarbonization of the energy sector. By means of an extensive literature review, the position of the energy community on the topic of digitalization, the regulatory framework around it, as well as the state of deployment of digital technologies in Europe are assessed. With the use of a survey as research tool, the impacts of digital technologies on the main stakeholders of the electricity system (namely, transmission and distribution system operators) are assessed. These are based on seven predefined Key Performance Indicators (KPIs) and classified into four main impact categories – technical, economic, environmental, and social. The results of the survey show not only a positive stand of system operators on digital technologies, but also highlight specific benefits and challenges brought about by their integration. By improving electricity networks observability and monitoring, digital technologies are enhancing electricity systems’ stability and reliability and improving operational efficiency, while at the same time favoring customer engagement and the integration of more renewable generation. The increased amount of data shared, however, comes with additional threats related to cyber-security and privacy. An extensive discussion of these and other benefits and challenges experienced by system operators due to digital technologies is provided in this work

Ceramic particles-based packed bed systems are attracting the interest from various high-temperature applications such as thermal energy storage, nuclear cooling reactors, and catalytic support structures. Considering that these systems work above 600 ◦C, thermal radiation becomes significant or even the major heat transfer mechanism. The use of coatings with different thermal and optical properties could represent a way to tune and enhance the thermodynamic performances of the packed bed systems. In this study, the thermal stability of several metallic (Inconel, Nitinol, and Stainless Steel) based coatings is investigated at both high temperature and cyclic thermal conditions. Consequently, the optical properties and their temperature dependence are measured. The results show that both Nitinol and Stainless Steel coatings have excellent thermal stability at temperatures as high as 1000 ◦C and after multiple thermal cycles. Contrarily, Inconel (particularly 625) based coatings show abundant coating degradation. The investigated coatings also offer a wide range of thermal emissivity (between0.6 and 0.9 in the temperature range of 400–1000 ◦C), and variable trends against increasing temperature. This work is a stepping-stone towards further detailed experimental and modelling studies on the heat transfer enhancement in different ceramic-based packed bed applications through using metallic coatings.

The present work performs a techno-economic analysis of a hybrid CSP - PV plant composed of a molten salt tower CSP running a supercritical CO2 power unit and a PV field. The two plants are connected in parallel, behind the meter. The PV unit produces power during daylight. The CSP plant stores thermal energy during the day to enable stable production during cloudy periods and enlarges the plant capacity factor while producing during the night. The plant performances have been evaluated in terms of capacity factor, thermal energy storage utilization factor, capital expenditure, and Levelised Cost of Electricity. The influence of plant solar multiple, storage size, supercritical CO2 nominal size, PV relative nominal size, receiver thermal efficiency, CO2 power unit, and PV cost assumptions has been assessed through different sensitivity analyses. The results show that it is worth hybridizing the system, indeed the PV unit can provide low-cost renewable power during the day, while the CSP unit can provide a cheap storage technology. Plant configurations leading to a Levelised Cost of Electricity lower than 70 $/MWhe can be identified already at relatively low nominal power size, 15 MWe. The receiver thermal efficiency is shown to be a highly important assumption, highlighting the need for further component development., QC 20220914Part of proceedings: ISBN 978-073544195-8

This work presents a laboratory scale 50kWhth prototype of an innovative radial flow packed bed thermal energy storage. The proposed storage has an inward radial heat transfer fluid flow during charge and a reverted fluid flow, by means of a valve arrangement, during discharge. The storage unit is equipped with differential pressure gauges, mass flow controller and 50?K-thermocouples to accurately measure the thermodynamic behavior of the unit. In order to assess the performance of the proposed thermal energy storage design two specific indicators have been introduced and defined, namely: the temperature uniformity, and the hydrodynamic uniformity. The results of preliminary CFD studies show a maximum temperature deviation of 20°C along the storage axial direction and uniformity indexes higher than 90%., Part of proceedings: ISBN 978-073544195-8QC 20220914

High-temperature thermal energy storage is recognized to be a key technology to ensure future sustainable energy generation. Packed bed thermal energy storage is a cost-competitive large-scale energy storage solution. The present work introduces the experimental investigation of an innovative 49.7 kWh(th) radial-flow type high-temperature packed bed thermal energy storage under dynamic mass flow rates. Various dynamic air flow rate profiles, representative of different potential applications, have been tested during the charging process to investigate their influence on the thermodynamic performance of the storage. The outlet thermal power during the discharge has been controlled by managing the air flow rate. Short operational cycles have also been performed. The results show that dynamic mass flow rates can lead to a thermal efficiency reduction between 0.5 % and 5 % with respect to static conditions. Controlling the air mass flow rate could be an efficient strategy to stabilize the thermal power output during the discharge while minimizing peaks in the pressure drop. This work testifies that specific dynamic boundary conditions should be included during the thermal storage design process since they could largely affect the unit thermodynamic performance and potential scale-up. If no specific dynamic profiles are available during the packed bed storage design stage, it is suggested to consider typical dynamic profiles of the air mass flow rate to guarantee limited efficiency reduction during operation., QC 20220809

High-efficient supercritical CO2 (sCO2) power blocks and the hybridization with solar photovoltaic (PV) plants have been identified as two viable solutions to enhance the economic competitiveness of Concentrating Solar Power (CSP) plants. This work introduces an innovative hybrid PV-CSP system layout with molten salt thermal energy storage and a sCO2 power block. An active hybridization has been proposed employing a molten salt electric heater that allows storing the excess PV production as thermal energy. The scalability of the plant has been investigated using size-dependent cost functions and introducing a novel methodology for scaling the sCO2 turbomachinery efficiencies. The conducted techno-economic optimizations show that the proposed hybrid PV-CSP plants can be cost-competitive. For a European solar resource location - 1900 kWh/(m2yr) - Levelized Cost of Electricity (LCOE) values lower than 66 EUR/MWh and capacity factors higher than 70 % can be achieved at 100 MWe. For a high-irradiance location - 3400 kWh/(m2yr) - a capacity factor of 85 % and a LCOE of 46 EUR/MWh have been found for the same scale. The selection of the sCO2 power cycle has a marginal impact on these results so that a simple recuperated cycle can yield similar LCOEs as the recompressed, reheated, and intercooled layouts. For smaller scales, systems with large gaps between the PV and CSP capacities are preferred, laying the optimal conditions for the electric heater integration with utilization factors up to 21 %., QC 20230613

A novel gas turbine simulator is developed to establish controllable boundaries for investigating the characteristics of key components in gas turbine based hybrid energy systems under different operating conditions. The gas turbine simulator consists of a compressed air system, an electrical heater, a mass flow controller, a proportional solenoid valve, a dual-flow choked nozzle, and a PLC-based control system. With the proposed control strategy, the fluid parameters, such as temperature, mass flow rate, and pressure, can be automatically regulated to simulate the boundary conditions of a gas turbine under various workloads. Experimental results for both cold and hot states have validated the capabilities of the gas turbine simulator to deliver convergent control results with fast response. The gas turbine simulator has demonstrated considerable performance in stabilizing system boundaries with the precision in terms of pressure control reaching +/- 0.004 bar for steady states, and +/- 0.018 bar to +/- 0.076 bar for transient states with mass flow and temperature perturbations. The gas turbine simulator can also accurately track linear and nonlinear trajectories during operating point migrations, and effectively limit deviations within +/- 0.037 bar., QC 20230314

The planning of energy infrastructures in new districts often follows the practice adopted for the rest of the city. In Stockholm, district heating is a common solution for multi-apartment neighborhoods. Recently, because of an average clean electricity mix, heat pumps have gained interest. However, European studies suggest to limit the reliance on electrification to avoid an extreme demand increase. Thus, an effort is required to improve the environmental impact of alternative options. This study proposes waste heat recovery in low temperature networks as a promising solution. By means of a techno-economic and environmental analysis, this option is compared to domestic heat pumps. A new approach is proposed to combine a district level perspective with simulation tools able to capture sector-coupling interactions. Scenarios, for a real neighborhood, assess waste heat recovery potential and electricity grid loading status. Results show that a waste heat recovery capacity equal to 10% of the peak load can reduce fossil fuel use of 40%. Local grid limitations are shown to be a bottleneck for the feasibility of domestic heat pumps. Their heat generation cost is 28% higher than for district heating. The carbon footprint is strongly dependent on the emission factor of the electricity mix (+11%/-24%)., ”Correction in: Energy. DOI: 10.1016/j.energy.2021.119874, Scopus: 2-s2.0-85099706973”, QC 20210127

Heat recovery from local resources is shown to be a promising solution to reduce the carbon footprint of district heating. Supermarkets equipped with a CO2 refrigeration system and a geothermal storage offer a larger heating capacity, compared to traditional solutions. While district heat could benefit from this higher heat recovery availability, supermarkets could generate an income from a capacity that would be otherwise unused. For the first time, this study applies a detailed modelling approach considering both sides of such a synergy. The objective is to assess the techno-economic and environmental impact of a coordinated control strategy. Since the heat recovery from the supermarket consumes additional electricity, power-to-heat is implemented as a solution to reduce the overall CO2 emissions. This is demonstrated by scenarios simulated for a district in Stockholm. Hourly electricity CO2 intensity and prices are implemented as signals to prioritize either the district heating central supply or heat recovery. By boosting the use of electricity when cleaner, a CO2 intensity-driven control show the potential of reducing the carbon footprint of the district (−9.4%). A control based on prices, instead, is more convenient economically both for the district (−1.4% heat cost) and for the supermarket (−32% operational cost)., QC 20210126

Solar cavity receivers are key components in point-focus concentrating solar power technologies due to their benefits of high efficiency and operating temperature. Accordingly, the enhancement of the optical performance can yield to significant improvements in the whole thermal power system. In this study, a geometrical optimization of an axial type impinging receiver for a solar dish Brayton system was analytically accomplished through Monte Carlo ray tracing method. By modeling a reference cylindrical cavity, optical surface properties and geometrical parameters were analyzed by dividing the cavity into three zones: front wall, middle wall and back wall. Simulation results show that the light flux peaking on the cylindrical wall can be significantly reduced when the cavity front wall is modified by changing the inclination angle; the light flux distribution over the absorber surface can be flattened by increasing the cavity radius; the irradiance distribution over the absorber can be efficiently adjusted by modifying the cavity back wall. After the cavity geometry optimization, the optical efficiency of the receiver can be enhanced by 3.34%, the material volume can be reduced by 20.1% and the peak flux on the cavity wall can be reduced by 38.6%, from 30 to 18.4 kW/m(2)., QC 20210127

Indirectly-irradiated receivers are widely used in most of the existing commercial concentrating solar power (CSP) plants. In order to compare the performances of the potential design strategies for the future high-temperature indirectly-irradiated receivers, a theoretical study has been conducted from a thermodynamic point of view. By analyzing the thermal circuit of the absorber wall, the roles of the heat flux through the wall and the total heat resistance have been observed to become more important to the receiver performances with increasing the concentration ratio. The influences of four parameters to the receiver performances have been analyzed: the convection heat transfer coefficient of the working fluid, the cavity shape factor, the thermal conductivity and the thickness of the absorber wall. Designing the absorber in a cavity shape has been proved to be an efficient way in enhancing the receiver performances by reducing the heat flux through the absorber wall. The advantage of the cavity receivers increases with increasing the concentration ratio, especially for gaseous working fluids which have relatively low heat transfer rates. The theoretical performance maps have been obtained for different potential design strategies, which will be helpful for making decisions in the future conceptual choice of receiver designs., QC 20210113

High-temperature thermal energy storage is becoming more and more important as a key component in concentrating solar power systems and as an economically viable large-scale energy storage solution. Ceramics and natural rocks based packed beds are one of the attracting solutions. For application temperatures above 600 ◦C, radiation heat transfer becomes the dominant heat transfer phenomenon and it greatly influences the performance of thermal storage systems. Coatings with different thermal properties (mainly thermal emissivity and thermal conductivity) could be exploited to modify the effective thermal properties of packed beds. In this work, we present a methodology to account for the thermal effect of a coating layer applied over the pebbles of a packed bed. The influences on the packed bed effective thermal conductivity of several characteristics of the coating material, packed bed arrangement, and filler material are investigated. The results show that low emissivity coatings could reduce the effective thermal conductivity of a rock based packed bed of about 58%, with respect to a similar uncoated solution, already at 800 ◦C. A low emissivity coating could also limit the increase in the thermal effective conductivity from the cold to the hot zone of the storage. Coatings would have a higher influence when applied in packed beds with large size particles, relatively high thermal conductivity of the substrate and void fraction. The application of different coatings, with various thermo-physical properties, in different parts of the storage could modify the effective thermal conductivity distribution and enable a partial control of the thermocline degradation, increasing the storage thermal efficiency., QC 20210211

The cavity wall is an important part of a cavity receiver in determining the receiver efficiency. Using solar selective reflector (SSR) materials with low solar absorptivity and high thermal emissivity for the cavity wall design is one efficient way to improve the receiver efficiency. In this work, we present a systematic study of the optical and high-temperature stability performances of six different SSR materials: one refractory ceramic fiber-based substrate material (Fiberfrax 140) and five metallic oxide coatings which are prepared by mixing metallic oxide powders of alumina, magnesium oxide and titanium dioxide with commercial inorganic adhesives. The thermal stability was studied by heating up and keeping the six candidate materials in atmospheric conditions at a temperature of 1250 ◦C for 200 h. The spectrum of hemispherical reflectance in the spectrum band 0.25–25 μmwas measured for analyzing the optical performance of the candidate materials. The obtained results show that all the six materials studied have good solar selective reflection characteristics, i.e, low solar absorptivity and relatively high thermal emissivity. Especially, the alumina-coated substrate material shows excellent performances both for thermal stability and solar selective reflection. The solar reflectivity can reach 94.6%., QC 20210623

Enhancing the operating temperature of concentrating solar power systems is a promising way to obtain higher system efficiency and thus enhance their competitiveness. One major barrier is the unavailability of suitable solar absorber materials for operation at higher temperatures. In this work, we report on a new high-temperature absorber material by combining Ti2AlC MAX phase material and iron-cobalt-chromite spinel coating/paint. This durable material solution exhibits excellent performance, passing the thermal stability test in an open-air environment at a temperature of 1250 degrees C for 400 h and at 1300 degrees C for 200 h. The results show that the black spinel coating can offer a stable high solar absorptivity in the range of 0.877-0.894 throughout the 600 h test under high temperatures. These solar absorptivity values are even 1.6-3.3% higher than that for the sintered SiC ceramic that is a widely used solar absorber material. Divergence of solar absorptivity during these relatively long testing periods is less than 1.1%, indicating remarkable stability of the absorber material. Furthermore, considering the simple application process of the coating/painting utilizing a brush followed by curing at relatively low temperatures (room temperature, 95 and 260 degrees C in sequence), this absorber material shows the potential for large-scale, high-temperature solar thermal applications., QC 20211103

A novel dual-flow choked nozzle based pressure controller is developed to achieve high-precision pressure control. The primary air flow is mainly used for offering the required mass flow to the test section, and the secondary air flow is used for regulating the total mass flow through the choked nozzle to achieve required pressure levels. The test results show that the precision of the stabilization of the pressure can reach +/- 0.005 bar for cold-state environments with air flow at ambient temperature, and +/- 0.015 bar for hot-state environments with air flow temperature in the range of 797.1-931.5 degrees C. Besides, this pressure controller has fast response. A new pressure steady state can be reached within 23.1 s for air flow at ambient temperature and 70 s for hightemperature scenario. Since no moving component exposed to the high-temperature air flow, it is very suitable for the pressurized test rigs with extremely high-temperature gas flow., QC 20211021

Well-integrated thermal energy storage units can enhance flexibility and profitability for a cogeneration system by enabling its decoupling of electricity and heat production. In the present study, novel latent heat thermal energy storage technologies are numerically investigated on their thermal and economic performance to evaluate their implementation at an existing combined cycle power plant. Three commercially available storage designs are analyzed: one shell-and-tube heat exchanger design based on planar spiral coils, and two types of advanced macro-encapsulated designs with capsules resembling ellipsoid and slab in shape, respectively. For the spiral coil design, three-dimensional flow velocity and temperature fields are simulated with finite volume method to predict the transient storage heat transfer process, including the effect of secondary flow induced by centrifugal forces. For the macro-encapsulated designs, effective heat transfer coefficients between heat transfer fluid (HTF) and phase change material (PCM) are inferred from scaled-down storage prototyping and testing. A onedimensional two-phase packed bed model was developed based on the apparent heat capacity-based enthalpy method to numerically study the heat transfer in macro-encapsulated PCM. With an operating temperature range of 46-72 degrees C and a HTF supplying flowrate range of 4.2-8.4 m3/h defined by the cogeneration strategy, thermal power and accumulated storage capacity are calculated and compared for the first three hours of charge and the first hour of discharge for the three designs. The effect from increasing the HTF flowrate to accelerate charging/ discharging processes is indicated by the simulation results. Performance comparison among the three designs shows that the slab capsule design exhibits the highest accumulated storage capacity (710 kWh) and state of charge (40%) after three hours of charge, though it has a lower theoretical total storage capacity (1760 kWh) than the spi, QC 20210915

To decarbonize and increase the flexibility in the heating and electricity sectors, large heat pumps, combined heat and power plants, renewables and storage technologies are increasingly being installed. This results in a tighter coupling between the electricity and heat distribution networks. Hence, the two networks need to be operated in an integrated way so that their synergies can be exploited. The main challenge in that regard is the lack of suitable tools that can capture the detailed operating parameters of both networks simultaneously. This paper proposes a population-based optimal power flow model for integrated heat and electricity distribution networks. An extended energy hub approach is used to model the components of the integrated energy system in a modular form. Active and reactive power balances, heat power balance and optimal management of storage technologies in the presence of intermittent renewables and variable tariffs are considered. The proposed method is then tested using a case study of highly coupled electricity and heat distribution networks consisting of a heat pump, a gas boiler, a combined heat and power plant, a wind turbine and a thermal storage together with a variable electricity tariff. It is found that above 97% of the surplus production from the wind power plant is effectively used in the system and 10.35% of the heat demand is effectively shifted from the peak hours to the cheap-electricity hours. The results show that the proposed method can be used as a decision support tool that can be used for the optimal integration of heat and electricity distribution networks. It also maximizes the synergy that can be captured from the multi-energy systems in general and from the heat and electricity distribution networks in particular., QC 20210819

This paper presents a thermo-economic optimisation of an electrified district heating network consisting of wind power plant, gas-fired combined heat and power plant and heat pumps. The load flow problem of the resulting multi-energy system is formulated by considering all physical and operating parameters in both of the electricity and heat distribution networks. First, energy and exergy analyses are applied to identify and isolate lossy branches of a meshed heating network. This is followed by the optimal placement of heat pumps. Finally, supply and return temperatures are optimised. Particle swarm optimisation technique is implemented in order to find the best place of heat pumps, their economical dispatch and optimal temperature profile of the district heating network. Results show that up to 59.12% of the distribution heat loss and 9.37% of the operating cost can be saved by following a step-by-step methodology discussed in this paper., QC 20210611

QC 20210303

High temperature thermal energy storages are becoming more and more important as a key component in concentrating solar power plants. Packed bed storages represent an economically viable large scale energy storage solution. The present work deals with the analysis and optimization of a packed bed thermal energy storage. The influence of quasi-dynamic boundary conditions on the storage thermodynamic performance is evaluated. The Levelized Cost of Storage is innovatively applied to thermal energy storage design. A complete methodology to design packed bed thermal energy storage is proposed. In doing so, a comprehensive multi-objective optimization of an industrial scale packed bed is performed. The results show that quasi-dynamic boundary conditions lead to a reduction of around 5% of the storage thermal efficiency. Contrarily, the effect of the investigated design variables over the TES LCoS optimization is only slightly influenced by quasi-dynamic boundary conditions. Aspect ratio between 0.75 and 0.9 would maximize the storage thermal efficiency, while low preliminary efficiency around 0.47 would minimize the Levelized Cost of Storage. This work testifies that quasi-dynamic boundary conditions should be taken into considerations when optimizing thermal energy storage. The Levelized Cost of Storage could be also considered as a more reliable performance indicator for packed bed thermal energy storage, as it is less dependent on variable boundary conditions., QC 20210315

El cambio climático no es un problema del futuro. El cambio climático es global, rápido y va en aumento. Una realidad. El último informe presentado por el Panel Intergubernamental sobre Cambio Climático (IPCC) destaca que el Antropoceno está detrás del aumento sin precedentes de las temperaturas, lo que lleva a eventos climáticos extremos como olas de calor, sequías, fuertes precipitaciones o ciclones tropicales. Se debe tomar acción climática. La transición energética juega un papel fundamental para el bienestar del planeta. Sin embargo, la financiación de energías renovables siempre ha sido un desafío. Lamentablemente, hasta la fecha, la transición energética ha carecido del soporte suficiente. En 2018, el sistema energético global estuvo por debajo del 50% de la inversión necesaria para mantener el calentamiento global por debajo de 1,5 ° C y evitar las peores consecuencias de la crisis climática [4]. Esta asombrosa estadística muestra claramente que la inversión debe reorientarse hacia la transición energética o deben abrirse nuevos canales de financiación. Seeds Renewables, una startup con sede en California, ha ideado una solución que tiene el potencial de cubrir una parte del déficit de la financiación al permitir que las personas inviertan en proyectos de energía renovable desde tan solo unos céntimos. Antes de permitir que sus usuarios inviertan, Seeds realiza el due diligence de los proyectos para determinar la viabilidad de la instalación. Se identifica que existe una falta de literatura pública y concisa sobre el proceso requerido para determinar la viabilidad técnica y la rentabilidad económica de los proyectos. Esta tesis sirve de guía para prestamistas, como Seeds Renewables, que tienen como objetivo realizar evaluaciones tecno económicas sobre instalaciones solares fotovoltaicas. Este objetivo central se complementa con listas de verificación cualitativas para el desarrollo de proyectos y una pauta legal para proporcionar una descripción general comp, Climate change is no longer a problem of the future. Climate change is global, rapid, and intensifying. A reality. The latest Intergovernmental Panel on Climate Change (IPCC) report highlights the Anthropocene is behind the unprecedent rising temperatures, leading to extreme weather events such as heatwaves, droughts, heavy precipitation, or tropical cyclones. Climate action must be taken. The energy transition plays a fundamental role when considering the wellbeing of the planet. However, renewable energy finance has always been a challenge. To date, the energy transition has been regrettably underfunded. In 2018, the global energy system was below 50 % of the investment required to keep global warming below 1.5 °C and avert the worst consequences of the climate crisis [4]. This staggering statistic clearly shows that financial investment needs to either be redirected to the energy transition, or new financing channels must be open. Seeds Renewables, a California-based startup, has come up with a solution which has the potential to cover a portion of the energy financing deficit by enabling people to invest in renewable energy projects from as little as their spare change. Before allowing their users to invest, Seeds carries out the due diligence of the projects to determine the feasibility of the installation. It is identified that there is a current lack of concise and public literature regarding the process required to determine the technical feasibility and economic profitability of projects. This thesis serves as a guide for lenders, such as Seeds Renewables, who aim to conduct techno-economic assessments on solar photovoltaic installations. This core objective is complemented by qualitative checklists for project development and legal due diligence to provide a comprehensive overview of the factors which surround the techno-economic analysis of solar arrays. Furthermore, the optimal software available in the market to carry out an analysis of solar photovolta, Klimatförändringarna är inte längre ett framtidsproblem. Klimatförändringarna är globala, snabba och intensifierande. En verklighet. Den senaste Intergovernmental Panel on Climate Change (IPCC) rapporten visar att Antropocen ligger bakom de aldrig tidigare skådade temperaturerna, vilket leder till extrema väderhändelser som värmeböljor, torka, kraftig nederbörd eller tropiska cykloner. Klimatåtgärder måste vidtas. Energiomställningen spelar en grundläggande roll när man överväger planetens välbefinnande. Finansiering av förnybar energi har dock alltid varit en utmaning. Hittills har energiomställningen tyvärr varit underfinansierad. År 2018 låg det globala energisystemet under 50% av investeringarna som krävs för att hålla den globala uppvärmningen under 1,5 ° C och avvärja de värsta konsekvenserna av klimatkrisen [4]. Denna häpnadsväckande statistik visar tydligt att finansiella investeringar antingen måste omdirigeras till energiomställningen eller att nya finansieringskanaler måste vara öppna. Seeds Renewables, en Kalifornienbaserad startup, har kommit fram till en lösning som har potential att täcka en del av energifinansieringsunderskottet genom att göra det möjligt för människor att investera i förnybara energiprojekt från så lite som deras växel. Innan de tillåter sina användare att investera, utför Seeds projektets due diligence -analys för att avgöra genomförbarheten av installationen. Det identifieras att det för närvarande saknas kortfattad och offentlig litteratur om processen som krävs för att bestämma projektens tekniska genomförbarhet och ekonomiska lönsamhet. Denna avhandling fungerar som en vägledning för långivare, till exempel Seeds Renewables, som syftar till att göra tekno-ekonomiska bedömningar av solcellsanläggningar. Detta kärnmål kompletteras med kvalitativa checklistor för projektutveckling och juridisk due diligence för att ge en övergripande överblick över de faktorer som omger den tekno-ekonomiska analysen av solsystem. Dessutom identifi

Climate change is no longer a problem of the future. Climate change is global, rapid, and intensifying. A reality. The latest Intergovernmental Panel on Climate Change (IPCC) report highlights the Anthropocene is behind the unprecedent rising temperatures, leading to extreme weather events such as heatwaves, droughts, heavy precipitation, or tropical cyclones. Climate action must be taken. The energy transition plays a fundamental role when considering the wellbeing of the planet. However, renewable energy finance has always been a challenge. To date, the energy transition has been regrettably underfunded. In 2018, the global energy system was below 50 % of the investment required to keep global warming below 1.5 °C and avert the worst consequences of the climate crisis [4]. This staggering statistic clearly shows that financial investment needs to either be redirected to the energy transition, or new financing channels must be open. Seeds Renewables, a California-based startup, has come up with a solution which has the potential to cover a portion of the energy financing deficit by enabling people to invest in renewable energy projects from as little as their spare change. Before allowing their users to invest, Seeds carries out the due diligence of the projects to determine the feasibility of the installation. It is identified that there is a current lack of concise and public literature regarding the process required to determine the technical feasibility and economic profitability of projects. This thesis serves as a guide for lenders, such as Seeds Renewables, who aim to conduct techno-economic assessments on solar photovoltaic installations. This core objective is complemented by qualitative checklists for project development and legal due diligence to provide a comprehensive overview of the factors which surround the techno-economic analysis of solar arrays. Furthermore, the optimal software available in the market to carry out an analysis of solar photovolta