Flexibility Services to Minimize the Electricity Production from Fossil Fuels. A Case Study in a Mediterranean Small Island

The design of multi-carrier energy systems (MES) has become increasingly important in the last decades, due to the need to move towards more efficient, flexible and reliable power systems. In a MES, electricity, heating, cooling, water and other resources interact at various levels, in order to get optimized operation. The aim of this study is to identify the optimal combination of components, their optimal sizes and operating schedule allowing minimizing the annual cost for meeting the energy demand of Pantelleria, a Mediterranean island. Starting from the existing energy system (comprising diesel generators, desalination plant, freshwater storage, heat pumps and domestic hot water storages) the installation of solar resources (photovoltaic and solar thermal) and electrical storage were considered. In this way, the optimal scheduling of storage units injections, water desalination operation and domestic hot water production was deduced. An energy hub model was implemented using MATLAB to represent the problem. All equations in the model are linear functions, and variables are real or integer. Thus, a mixed integer linear programming algorithm was used for the solution of the optimization problem. Results prove that the method allows a strong reduction of operating costs of diesel generators also in the existing configuration

Ocean Energy in Belgium - 2019

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Island-based polygeneration systems : feasibility of bBiomass-driven distributed concepts

The colossal risks and challenges posed by climate change require innovative solutions that must fulfil energy service demands sustainably. The concept of small-scale, biomass-based polygeneration (SBP) is one such technological approach, which optimizes locally supplied fuels to provide several energy services like electricity, heating, cooling, potable water, and/or bio-chemical products. By presenting chosen SBP systems and models employed in various socio-geographic locations, in particular distributed applications, the thesis identifies benefits as well as drawbacks of the SBP concept and aims to promote its wider usage in the field. Because a multitude of technologies can be applied for polygeneration system design, the thesis starts with a thorough review of the highly complex and rapidly evolving field, where relevant literature is presented and assimilated. Based on this review, several models have been created for various solar-assisted SBP systems: Firstly, a small-scale Combined Cooling, Heating, and Power (CCHP) system based on biomass gasification has been investigated for a hotel resort on one of the Andaman Islands, India. Apart from economic and environmental superiority compared to a fossil-fuel reference system, the study also expanded technological aspects by adding a socio-political analysis of the benefits and drawbacks of the system for the entire island community. In the second study, a novel control algorithm was devised for a biogas-based polygeneration system generating electricity and potable water generation for a rural off-grid village in El Pando, Bolivia. It was found that the proposed system could lead to significant cost and emissions reductions paired with greater energy autonomy. In the third study, an optimization model for a combined gasification-based CCHP/Heat Pump (HP) system is presented for a tourist facility in Barcelona considering various climate scenarios. The study reveals that the system design is only slightly affected by future changes in climate and that the CCHP/HP system shows only a moderate economic performance but still considerable CO2-savings potential. The overall findings of these studies reveal that the economic feasibility of SBP systems depends greatly not just on their inherent design but also on their location. However, all proposed polygeneration systems could lower emissions significantly, while excelling in energy efficiency as well as adaptability towards service demands and other technologies. The presented studies contribute to the state of the art by adding innovative polygeneration system designs, proposing new modelling approaches and subsequent models including SBP system enhancing technologies, as well as by investigating the effects of geographical location and climate change on the system design process.Los colosales riesgos y retos puestos por el cambio climático requieren soluciones creativas para satisfacer las demandas de servicios energéticos de una manera más sostenible, comparado con los sistemas actuales. El concepto de poligeneración a escala pequeña y basada en biomasa (Small-scale, biomass-based polygeneration o SBP) es uno de estos enfoques, que optimiza el uso de combustible locales para proveer varios servicios energéticos como electricidad, calor, enfriamiento, agua potable y/o productos bioquímicos. Presentando una selección de sistemas SBP y modelos empleados en varias localizaciones socio-geográficas, esta tesis identifica los beneficios e inconvenientes del concepto SBP con el objetivo de promover su un uso más amplio en el mundo. Como se puede aplicar una multitud de tecnologías para el diseño de sistemas SBP, la tesis empieza con una revisión profunda del campo, altamente complejo y dinámico, donde la literatura relevante está presentada en una forma estructurada y resumida. Basado en esta revisión, se han creado varios modelos SBP para varios sistemas SBP con asistencia solar: Principalmente, se ha investigado un sistema de generación conjunta de frio, calor y electricidad (en inglés: Combined Cooling, Heating, and Power or CCHP) basado en gasificación de biomasa para un resort (hotelero) en una de las islas Andamán, India. Además de mostrar de una superioridad económica y ambiental comparado con el sistema de referencia de combustibles fósiles, el estudio expandió el conocimiento científico añadiendo un análisis socio-político de los beneficios e inconvenientes del sistema SBP para la comunidad de la isla entera. En el segundo estudio, se ha desarrollado un nuevo algoritmo de control para un sistema de poligeneración basado en biogás, que genera electricidad y agua potable para una comunidad rural y sin conexión a una red eléctrica más grande en el Pando, Bolivia. Se ha revelado que el sistema propuesto podría bajar significantemente los costes y las emisiones junto con un aumento de la autonomía energética. En el tercer estudio se ha presentado un modelo de optimización para un sistema combinado de CCHP y bombas de calor (sistema CCHP/HP), que se considera para una estructura museístico-turística en Barcelona y para varios escenarios climáticos. En el estudio se ha descubierto que el cambio climático influye sólo ligeramente en el diseño del sistema óptimo, y que el sistema CCHP/HP demuestra sólo un moderado desempeño económico, similar al convencional, pero también un potencial considerable para la reducción de emisiones de CO2. El conjunto de los estudios revela que la viabilidad económica de los sistemas SBP depende altamente no solo de su diseño inherente, sino también de su entorno. De todos modos, todos los sistemas SBP propuestos podrían bajar las emisiones significantemente, mientras sobresalen en eficiencia energética y adaptabilidad a servicios energéticos y tecnologías alternativas. Los estudios presentados contribuyen al estado del arte añadiendo diseños innovadores de sistemas SBP, proponiendo nuevos enfoques de modelado y cálculo, y subsecuentemente nuevos modelos incluyendo tecnologías aumentando sistemas SBP, e investigando los efectos de la ubicación geográfica y del cambio climático al proceso del diseño de los sistemas SBP.Sammanfattning Klimatförändringen bär med sig kolossala risker och utmaningar, som kräver innovativa lösningar för att tillhandahålla energitjänster på ett mer hållbart sätt än med tidigare energisystem. Konceptet med småskaliga, biomassa-baserade polygeneration (SBP) system är ett sådant teknologiskt tillvägagångssätt, vilket optimerar användningen av lokalt producerat bränsle för att tillhandahålla olika energitjänster som elektricitet, värma, kyla, dricksvatten, eller/och bio-kemiska produkter. Doktorsarbetet identifierar för- och nackdelar hos olika SBP konceptet genom att presentera ett urval av SBP system och modeller av dem för olika geografiska regioner, med mål att främja vidare applikation av dem i fält. Eftersom en mängd tekniker kan användas för design av polygenerationssystem, börjar avhandlingen med en grundlig genomgång av det mycket komplexa och snabbt utvecklande området, där relevant litteratur presenteras och assimileras. Baserat på denna recension har flera modeller skapats för olika solassisterade SBP-system: För det första har ett småskaligt kombinerat kyl-, värme- och kraftsystem (CCHP) baserat på biomassaförgasning undersökts för en hotellanläggning på en av Andamanöarna, Indien. Bortsett från ekonomisk och miljömässig överlägsenhet jämfört med ett referenssystem för fossila bränslen har studien även inkluderat tekniska aspekter genom att lägga till en socio-politisk analys av fördelarna och nackdelarna med systemet för hela ö-samhället. I den andra studien utvecklades en ny regleralgoritm för ett biogasbaserat polygenereringssystem som genererar el och renar vatten till dricksvatten för en by utan elförsörjning i El Pando, Bolivia. Det konstaterades att det föreslagna systemet kan leda till betydande kostnads- och utsläppsminskningar i kombination med större energiautonomi. I den tredje studien presenteras en optimeringsmodell för ett kombinerat förgasningsbaserat CCHP / värmepumpsystem (HP) för en turistanläggning i Barcelona under olika klimatscenarier. Studien avslöjar att systemdesignen bara i låg grad påverkas av framtida klimatförändringar och att CCHP / HP-systemet endast visar en måttlig ekonomisk prestanda men fortfarande en betydande potential för CO2-besparingar. De övergripande resultaten av dessa studier visar att den ekonomiska genomförbarheten för SBP-system inte bara beror på deras inneboende design utan också på deras lokalisering. Alla föreslagna SBP-system kan emellertid sänka emissionerna betydligt, samtidigt som de sticker ut i energieffektivitet samt anpassningsbarhet efter energitjänster och annan teknik. De presenterade studierna bidrar till vetenskapen genom att lägga till innovativa SBP-systemdesigner, föreslå nya modelleringsmetoder och efterföljande modeller inklusive SBP-systemförbättrande teknik, samt genom att undersöka effekterna av geografisk plats och klimatförändringar på systemdesignprocessenErasmus Mundus en serveis energètics sostenible

Sustainable Design of Urban Rooftop Food-Energy-Land Nexus

Funding Information: Authors in particular M.G. would like to acknowledge the UK Engineering and Physical Sciences Research Council ( EPSRC ) for providing financial support for research under project “Resilient and Sustainable Bio-renewable Systems Engineering Model” [ EP/N034740/1 ]. A.H. would like to acknowledge financial support from Natural Environment Research Council (NERC) ADVENT project [ 1806209 ].Peer reviewedPublisher PD

Assessment of energy, mobility, waste, and water management on Italian small islands

Small islands are recognized for their vulnerability to climate change. In this context, mitigation and adaptation policies are needed, but the ecological transition must be based on data. This study aims to assess the level of sustainability reached by 26 of the inhabited Italian small islands; it collects and analyzes the data and initiatives on the energy, mobility, waste, and water sectors and discusses the islands’ steps toward sustainability. The findings show that 18 of the 26 islands are not interconnected with the national grid and that the renewable sources cover less than 5% of the energy demand on 25 of the 26 islands. The number per capita of private vehicles reaches 90 cars per 100 inhabitants on three islands. The average of the separate collection of waste on the islands is 52%, which is far from the minimum recommended threshold of 65%. Pipelines or tankers on 17 of the 26 islands guarantee the water supply, and desalination plants are still not the rule, while the presence of wastewater treatment has been detected on 12 islands, and it often provides only partial treatment. An ambitious multi-stakeholder sustainability plan for each island should be developed to overcome the typical barriers of the island and to increase the building capacity in order to use economic incentives for that goal

Editorial: SDEWES science - The path to a sustainable carbon neutral world

In 2021, the 16th SDEWES (Sustainable Development of Energy, Water and Environment Systems) Conference was held in Dubrovnik (Croatia), October 10th – 15th and delivered more than 690 contributions, presented in regular and 13 special sessions, with 7 invited lectures devoted to various sustainability topics. The Energy journal has continued its cooperation with SDEWES launching a special issue dedicated to this SDEWES Conference. The 29 selected papers cover a wide variety of issues in the fields of energy, water and environment, and all of them propose novel approaches or remarkable advances in well established research lines already explored in past SDEWES Conferences

Multi-terminal HVDC grids with inertia mimicry capability

The high-voltage multi-terminal dc (MTDC) systems are foreseen to experience an important development in the next years. Currently, they have appeared to be a prevailing technical and economical solution for harvesting offshore wind energy. In this study, inertia mimicry capability is added to a voltage-source converter-HVDC grid-side station in an MTDC grid connected to a weak ac grid, which can have low inertia or even operate as an islanded grid. The presented inertia mimicry control is integrated in the generalised voltage droop strategy implemented at the primary level of a two-layer hierarchical control structure of the MTDC grid to provide higher flexibility, and thus controllability to the network. Besides, complete control framework from the operational point of view is developed to integrate the low-level control of the converter stations in the supervisory control centre of the MTDC grid. A scaled laboratory test results considering the international council on large electric systems (CIGRE) B4 MTDC grid demonstrate the good performance of the converter station when it is connected to a weak islanded ac grid.Peer ReviewedPostprint (author's final draft

Stand-alone hybrid renewable energy systems (HRES)

End of Energy Poverty and achieving Sustainable Energy for all by 2030 is a universal challenge. 1.3 billion people without energy access and 2.8 billion people using unsustainable solid fuel for cooking and heating are global challenges for human and societal sustainable development. Nearly 1 trillion of investment is expected in the Sustainable Energy for All (SE4ALL) scenario to achieve universal energy access in 2030. Around 60% of investments will be in isolated off-grid and mini-grid systems with the relevant goal of duplicating the renewable energy sources in the energy mix. Access to innovation trends in renewable energy off-grid would benefit future installations. This work brings to light the recent years research contributions in Hybrid Renewable Energy Systems (HRES) and related aspects that would benefit these required investments in isolated off-grid and mini-grid systems. An overview on the thematic focus of research in Hybrid Renewable Energy Systems (HRES) in the last decade, period 2005 - 2015, is provided. This review covers multiple key aspects of HRES as the main focus of the research (technical, economical, environmental, financial, etc.); the design of the system (type of load, energy sources, storage, availability of meteorology data, etc.); different optimization criteria and objective function; software and modelling tools; and the type of application and country among others. A methodology for searching, identifying and categorizing the innovations related to HRES is proposed. Applying this methodology during this PhD work results in a primary database with a categorized bibliography including nearly 400 entries. Currently system design is mainly technical driven with economic feasibility analysis regarding the energy cost. As for environmental aspects, the beneficial impacts of renewable energy are hardly introduced as an economical value that is so far the most important decision-making criteria. Regarding decision-making tools, the most currently used optimization algorithms and software tools for the design of HRES is HOMER and a case study for understanding is proposed. Following the analysis of most popular and relevant criteria, an easy to use guideline is proposed encouraging decision-making for more sustainable energy access. There are untapped research opportunities for HRES in multi-disciplinary thematic areas. The analysis of innovations regarding the system design for Hybrid Renewable Energy Systems (HRES) have identified potential for research community aligned with the trends to integrate the value chain and foster innovative business models and sustainable energy markets. After the analysis of those different focus that goes from technical and economical, to environmental, regulatory or policy aspects, an integrated value chain for HRES systems is defined. Knowledge, methodologies & tools are provided in this PhD work for more stand-alone hybrid systems creating value for more of the stakeholders involved. After reviewing the latest innovations in HRES per thematic focus, an integrated value chain for those systems has been proposed and multidisciplinary research opportunities have been identified. Identifying the need to include the environmental aspects in early stages of the decision-making has lead to propose an easy to use guideline integrating most relevant criteria for the design of stand-alone renewable power systems. Finally, the research opportunities identified and the untapped potential of transferring latest innovations have result in the creation of the website ElectrifyMe (www.electrifyme.org) to enable valuable international networking contacts among researchers and encouraging multi-disciplinary research. "Knowledge, methodologies & tools" are powerful contributions by research community and innovators to foster more sustainable energy for all.El fi de la pobresa energètica i l'assoliment d'energia sostenible per a tothom l'any 2030 és un repte universal. 1,3 mil milions de persones sense accés a l'energia i 2,8 mil milions de persones que utilitzen combustible sòlid insostenible per cuinar i escalfar són desafiaments globals pel desenvolupament humà sostenible i social. S'espera una inversió aproximada de 1 trilió en l'energia sostenible per a tots (SE4ALL) per aconseguir l'accés universal a l'energia en 2030. Al voltant del 60 % de les inversions seran en sistemes off-grid i mini-grid, amb la corresponent meta de duplicar les fonts d'energia renovables en el mix energétic. En aquesta tesis es facilita una visió general sobre els àmbits temàtics de la recerca en Hybrid Renewable Energy Systems (HRES) en l'última dècada, període 2005-2015. Aquesta revisió es refereix a diversos aspectes clau deis HRES com: el focus principal de la investigació (tècnics, econòmics, ambientals, financers, etc.); el disseny del sistema (tipus de carrega, fonts d'energia, l'emmagatzematge, la disponibilitat de dades de meteorologia, etc.); diferents criteris d'optimització i funció objectiu; programari de modelatge eines; i el tipus d'aplicació i el país, entre d'altres. Es proposa una metodologia per buscar, identificar i categoritzar les innovacions relacionades amb els HRES. L'aplicació d'aquesta metodologia durant aquest treball de doctorat proporciona una base de dades primaria amb una bibliografia classificada incloent prop de 400 entrades. Actualment el disseny dels sistemes incorporen criteris tècnics amb anàlisi de viabilitat econòmica sobre el cost de l'energia. Pel que fa a les eines de presa de decisions, el métode d'optimització més utilitzats en l'actualitat pel disseny de HRES és HOMER, i es proposa un estudi de cas per a la comprensió deis criteris de disseny. Després de l'anàlisi de la majoria deis valors més habituals i rellevants, es proposa una senzilla guia per la presa de decisions per a l'accés a l'energia més sostenible. Després de compartir innovacions i proporcionar metodologies i eines, facilitar la creació de xarxes entre els investigadors ha demostrat ser una poderosa acció per promoure recerca sense explotar amb equips multidisciplinaris i internacionals. La pàgina web ElectrifyMe (www .electrifyme .org) ha estat creada amb la finalitat de facilitar a la comunitat d'investigació descobrir les innovacions i compartir projectes . Coneixements, metodologies i eines es proporcionen en aquest treball de doctorat per afavorir la creació de valor als sistemes aïllats híbrids renovables (stand-alone HRES) pels actors involucrats. Després de revisar les últimes innovacions en la introducció de renovables en sistemes aïllats en diferent enfoc temàtic, s'han estat identificat oportunitats de recerca multidisciplinars i s'ha proposat una cadena de valor integrada per aquests sistemes. La identificació de la necessitat d'incloure els aspectes ambientals en les primeres etapes de la presa de decisions ha portat a proposar una guia fàcil per utilitzar la integració de criteris més rellevants pel disseny de sistemes d'energia renovables independents. Finalment, tes oportunitats de recerca identificades i el potencial sense explotar de transferir les darreres innovacions tenen com a resultat la creació de la pàgina web ElectrifyMe (www.electrifyme.org) per promoure contactes i col·laboracions de xarxes internacionals entre investigadors i el foment de la investigació multidisciplinar. "El coneixement, les metodologies i les eines són poderoses contribucions de la comunitat de recerca per assolir un accés sostenible a l'energia per tots