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Sánchez-García, L., Averfalk, H., Hermoso-Martínez, N., Hernández-Iñarra, P., Möllerström, E. & Persson, U. (2025). Feasibility of district heating in a mild climate: A comparison of warm and cold temperature networks in Bilbao. Applied Energy, 378, Article ID 124384.
Open this publication in new window or tab >>Feasibility of district heating in a mild climate: A comparison of warm and cold temperature networks in Bilbao
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2025 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 378, article id 124384Article in journal (Refereed) Published
Abstract [en]

District heating and cooling systems can aid in decarbonisation and the provision of efficient heating and cooling in Europe. However, whereas these systems have achieved high penetration rates in colder climates of Northern, Central and Eastern Europe, they remain marginal in milder climates of Southern Europe. In terms of network design, district heating and cooling systems can be configured in different ways. In so-called warm networks, the required temperature for all the consumers is attained city-wide, and in so-called cold systems, the necessary temperature is achieved at the consumers' premises by ancillary equipment. The most cost-effective heating and cooling solution for urban areas requires investigation. This research models and compares cold and warm district energy systems with other heating and cooling solutions through a comprehensive case study executed in the city of Bilbao, Spain. The city is characterised by a mild climate and a high population density which is characteristic of many Southern European cities. The results show that district energy systems are economically advantageous compared to other low-carbon solutions, such as air-source heat pumps. However, these systems are not able to outcompete natural gas under current cost and taxation levels. Warm networks provide a cheaper source of heat compared to cold networks, but both network types lead to similar expenditures for combined heating and cooling supply. This paper, presents the study context and its results, and is complemented by an exhaustive detailed methodology document and a separate supplementary material repository. © 2024 The Authors

 

Place, publisher, year, edition, pages
Oxford: Elsevier, 2025
Keywords
District heating, District cooling, Warm network, Cold network, LCOE, Spain, Southern Europe
National Category
Energy Engineering
Research subject
Smart Cities and Communities
Identifiers
urn:nbn:se:hh:diva-54818 (URN)10.1016/j.apenergy.2024.124384 (DOI)
Projects
Decarb City Pipes 2050 - Transition roadmaps to energy efficient, zero-carbon urban heating and cooling
Funder
Halmstad UniversityEU, Horizon 2020, 893509
Available from: 2024-11-01 Created: 2024-11-01 Last updated: 2024-11-13Bibliographically approved
Negash, T., Solomon, A., Ottermo, F., Möllerström, E., Seres, I. & Farkas, I. (2025). Strategies for integrating residential PV and wind energy in Eritrea's electricity grid by imposing feed-in constraints in low voltage network. Solar Energy, 286, Article ID 113140.
Open this publication in new window or tab >>Strategies for integrating residential PV and wind energy in Eritrea's electricity grid by imposing feed-in constraints in low voltage network
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2025 (English)In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 286, article id 113140Article in journal (Refereed) In press
Abstract [en]

The global shift towards renewable energy necessitates careful planning and integration strategies, especially in regions like Eritrea, which have abundant solar and wind resources but limited grid infrastructure. This study explores strategies for maximizing direct renewable energy consumption by incorporating residential photovoltaic (PV) and wind energy into Eritrea's electricity grid. Our research offers a unique approach by proposing tailored grid expansion and management strategies to maximize renewable integration, specifically designed for the context of developing countries like Eritrea, addressing the specific challenges posed by limited infrastructure and data availability. By analyzing historical data and using simulation techniques, the study explored the ideal deployment of PV and battery storage systems to maximize penetration while minimizing curtailment, using a straightforward algorithm for PV injection, battery charging, and discharging for each hour of the year. Key findings reveal that imposing feed-in limit and integrating battery storage significantly reduce curtailment, with a feed-in limit of 0.4 to 0.5 kW/kWp and battery storage below 2 kWh/kWp yielding best results. The analysis also highlights the trade-off between installing additional PV capacity and battery capacity, especially at lower renewable capacity levels. In certain scenarios it is found that curtailment is preferred over storage, particularly at lower PV capacities. The study emphasizes the crucial role of storage utilization and balancing generators in maintaining grid stability during adverse weather and peak demand. These insights provide valuable guidance for policymakers and grid planners to advance sustainable energy strategies and achieve ambitious renewable energy targets in Eritrea. © 2024 The Author(s)

Place, publisher, year, edition, pages
Oxford: Elsevier, 2025
Keywords
Battery storage, Curtailment, Feed-in limit, Low voltage grid, Penetration, Residential PV
National Category
Energy Engineering Energy Systems
Identifiers
urn:nbn:se:hh:diva-55061 (URN)10.1016/j.solener.2024.113140 (DOI)2-s2.0-85211341545 (Scopus ID)
Available from: 2024-12-10 Created: 2024-12-10 Last updated: 2024-12-18Bibliographically approved
Ivanell, S., Liljenfeldt, J., Möllerström, E., Ottermo, F. & Spansk, K. (2025). Vindkraft (1ed.). Lund: Studentlitteratur AB
Open this publication in new window or tab >>Vindkraft
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2025 (Swedish)Book (Other academic)
Place, publisher, year, edition, pages
Lund: Studentlitteratur AB, 2025 Edition: 1
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-55237 (URN)9789144193946 (ISBN)
Available from: 2025-01-14 Created: 2025-01-14 Last updated: 2025-02-05Bibliographically approved
Gadd, H., Atabaki, M. S., Gong, M., Möllerström, E., Norrström, H., Ottermo, F., . . . Werner, S. (2024). 70 New Possibilities for District Heating. Stockholm: Energiforsk AB
Open this publication in new window or tab >>70 New Possibilities for District Heating
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2024 (English)Report (Other academic)
Abstract [en]

The ongoing transformation in European district heating systems fromthe usage of fossil-based technologies to non-fossil heat supplies issummarised by a collection of 70 possibilities linked to decarbonisation. These possibilities are exemplified by 284 implemented, planned, orproposed cases. The 70 possibilities for decarbonised district heatinginclude using heat, connecting customers, moving heat, storing heat, removing carbon dioxide, and supplying heat together with somefeatures for the entire value chain, to heat usage from heat generation orrecycling. This collection of 70 possibilities is neither complete nor doesit contain any recommendations for the possibilities or advocate forspecific possibilities.

The purpose of this project was to provide an extensive inventory ofdecarbonisation activities recently performed by district heating operators andother heat suppliers. These decarbonisation activities include the directsubstitution of heat obtained from the combustion of fossil fuels and indirectactions for obtaining more efficient district heating systems. These indirect actionsreduce costs and increase revenue, thereby improving the competitiveness ofdistrict heating. The time horizon, which is linked to the EU’s target for thereduction of greenhouse gas emissions by 55% compared to 1990 levels, is 2030. This inventory of early decarbonisation projects concerning district heatingsystems has revealed the following three key conclusions.

First, decarbonisation activities can be divided into substituting and supportingpossibilities. Substituting possibilities in heat supply include linear supply fromrenewables, heat recycling from processes that generate excess heat, and non-fossilways of meeting peak heat demands during very cold days. The linear heat supplyis based on geothermal heat, solar heat, and electricity supply. Heat recycling ispossible from various processes related to biorefineries, hydrogen supply, petrochemical plants, electricity distribution, district cooling, data centres, batteryfactories, food supply chains, and sewage waters. Heat storage can make heatdelivery more independent of heat supply and provide additional opportunities toreduce peak loads. Supporting possibilities mainly comprise activities forobtaining lower temperatures in heat distribution networks to increase profitabilitywhen using low-temperature heat sources. These activities are performed whenconnecting customers, moving heat, and using heat. Another supporting activity is the removal of biogenic carbon dioxide from the natural carbon cycle, although anappropriate international accounting system for its removal is still missing.

Second, the decarbonisation possibilities of district heating systems differ fromthose of traditional systems based on fossil fuels. The availability ofdecarbonisation possibilities for district heating depends on local conditions,whereas fossil fuels are transported from available global resources and are usedworldwide. Hereby, decarbonised district heating systems will not be as uniformas traditional systems based on fossil fuels. The local conditions lower the degrees of freedom for the implementation of substituting possibilities in existing buildingsand systems. Hence, it is important to adopt new methods for utilising the highestdegree of freedom possible in new buildings and systems.

Third, the common denominators for the 70 identified possibilities are degrees offreedom for decarbonisation, action plans for achieving lower heat distributiontemperatures, the use of heat pumps for upgrading low-temperature supplies tomeet high-temperature demands, smart digitalisation options, clear supplyresponsibilities, favourable institutional frameworks, and digital planning models. These seven common denominators are efficient tools for obtaining decarbonisedand more efficient district heating systems in the future. These redesigned and newsystems will be somewhat different than traditional systems, which have beenbased on a district heating technology that was originally elaborated for systemsbased on fossil fuels.

Place, publisher, year, edition, pages
Stockholm: Energiforsk AB, 2024. p. 219
Keywords
Decarbonisation, possibilities, cases, district heating, transformation, Europe
National Category
Energy Engineering
Research subject
Smart Cities and Communities, PROACTS
Identifiers
urn:nbn:se:hh:diva-54567 (URN)978-91-89919-40-2 (ISBN)
Funder
Energy Research, 350966
Available from: 2024-09-06 Created: 2024-09-06 Last updated: 2024-10-24Bibliographically approved
Gadd, H., Atabaki, M. S., Gong, M., Möllerström, E., Norrström, H., Ottermo, F., . . . Werner, S. (2024). 70 nya möjligheter för fjärrvärme. Stockholm: Energiforsk AB
Open this publication in new window or tab >>70 nya möjligheter för fjärrvärme
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2024 (Swedish)Report (Other academic)
Abstract [sv]

Den pågående omvandlingen av europeiska fjärrvärmesystem från användning av fossilbaserad teknik till icke-fossil värmeförsörjning sammanfattas med en utvald samling av 70 möjligheter kopplade till fossilfrihet. Dessa möjligheter exemplifieras med 284 genomförda, planerade eller föreslagna fall. De 70 möjligheterna för koldioxidfri fjärrvärme omfattar att använda värme, ansluta kunder, flytta värme, lagra värme, avskilja koldioxid och tillföra värme tillsammans med några aspekter för hela värdekedjan till värmeanvändning från värmeåtervinning eller värmegenerering. Uppsättningen av 70 möjligheter är varken komplett eller innehåller några rekommendationer för vilka möjligheter som bör användas. Syftet med detta projekt har varit att tillhandahålla en omfattande inventering av tidiga aktiviteter för att erhålla fossilfri fjärrvärme som nyligen utförts av fjärrvärmeföretag eller andra värmeaktörer. Dessa aktiviteter omfattar både direkt substitution av värme som tidigare erhållits från förbränning av fossila bränslen och stödjande indirekta åtgärder för att erhålla mer effektiva fjärrvärmesystem. Dessa stödjande åtgärder minskar kostnaderna eller ökar intäkterna som förbättrar fjärrvärmens konkurrenskraft. Tidshorisonten har varit 2030, kopplat till EU:s mål för minskning av växthusgasutsläppen med 55 % jämfört med 1990 års utsläpp. Denna inventering av tidiga projekt för fossilfri fjärrvärme har givit följande tre viktiga slutsatser. För det första, aktiviteter för fossilfri fjärrvärme kan delas in i ersättande och stödjande möjligheter. Ersättande möjligheter i värmeförsörjningen inkluderar linjär försörjning från förnybar energi, värmeåtervinning från processer som genererar restvärme och icke-fossila sätt att möta spetsbehov under mycket kalla dagar. Den linjära värmeförsörjningen baseras på geotermisk värme, solvärme och eltillförsel. Nya aktiviteter för värmeåtervinning är möjliga från många olika samhällsprocesser, såsom bioraffinaderier, vätgasförsörjning, petrokemiska anläggningar, eldistribution, fjärrkyla, datacenter, batterifabriker, livsmedelsförsörjning och avloppsvatten. Värmelager kan göra värmeleveransen mer oberoende av värmetillförseln, vilket också ger ytterligare möjligheter att minska spetsbelastningar. Stödjande möjligheter innehåller främst aktiviteter för att erhålla lägre temperaturer i värmedistributionsnät, vilket ökar lönsamheten vid användning av lågtempererade värmekällor. Dessa aktiviteter utförs när man använder värme, ansluter kunder och flyttar värme. En planerad stödaktivitet är också avskiljning av biogen koldioxid från det naturliga kolkretsloppet, även om ett lämpligt internationellt ersättningssystem för detta fortfarande saknas. För det andra, karaktären hos möjligheterna till fossilfritt skiljer sig från de traditionella erfarenheterna baserade på fossila bränslen. Tillgången på möjligheter till fossilfritt beror på lokala förhållanden, medan fossila bränslen transporterades från tillgängliga globala resurser, vilket gav full frihet att använda fossila bränslen var som helst i världen. Härigenom kommer fossilfria fjärrvärmesystem inte bli så 4likartade som traditionella fjärrvärmesystem var med fossila bränslen. De lokala förutsättningarna för fossilfri fjärrvärme ger något lägre frihetsgrader för implementering av ersättande möjligheter i befintliga byggnader eller system. Därför är det viktigt för framtiden att utnyttja den högre frihetsgrad som är möjlig i nya byggnader och system genom att använda nya metoder mm. För det tredje, de gemensamma nämnarna för de 70 identifierade möjligheterna är antal frihetsgrader för fossilfrihet, handlingsplaner för att erhålla lägre temperaturer i värmedistributionsnät, olika sätt att använda värmepumpar för att uppgradera låga framtemperaturer för att tillgodose högre temperaturbehov hos kunderna, möjliga smarta digitaliseringsalternativ, tydliga leveransansvar, gynnsamma institutionella ramar samt digitala planeringsverktyg. Dessa sju gemensamma nämnare är effektiva verktyg för att få mer effektiva fossilfria fjärrvärmesystem, eftersom den traditionella fjärrvärmetekniken en gång i tiden utformades för system baserade på användning av fossila bränslen. 

Place, publisher, year, edition, pages
Stockholm: Energiforsk AB, 2024. p. 218
Keywords
Fossilfritt, möjligheter, fall, fjärrvärme, omvandling, Europa
National Category
Energy Engineering
Research subject
Smart Cities and Communities, PROACTS
Identifiers
urn:nbn:se:hh:diva-54566 (URN)978-91-89919-39-6 (ISBN)
Funder
Energy Research, 350966
Available from: 2024-09-06 Created: 2024-09-06 Last updated: 2025-01-23Bibliographically approved
Möllerström, E. & Gipe, P. (2024). The History of Wind Power. In: Ossama Abdelkhalik; Mohammad Amin Makarem; Mohammad Rasul (Ed.), Encyclopedia of Renewable Energy, Sustainability and the Environment: Volume 3: Hydropower, Marine Energies, and Wind Power Applications (pp. 151-162). Amsterdam: Elsevier
Open this publication in new window or tab >>The History of Wind Power
2024 (English)In: Encyclopedia of Renewable Energy, Sustainability and the Environment: Volume 3: Hydropower, Marine Energies, and Wind Power Applications / [ed] Ossama Abdelkhalik; Mohammad Amin Makarem; Mohammad Rasul, Amsterdam: Elsevier, 2024, p. 151-162Chapter in book (Refereed)
Abstract [en]

Wind power received sporadic interest after the breakthrough of electricity in the late 1800s, but was sidelined by other electricity generation technologies until the 1970s. A renewed interest in alternative energy sources during the 1970s spurred the development of wind turbines, which gradually evolved into the modern large wind turbines. Whereas significant attention and financial support were focused on government-funded multi-MW prototypes, the small wind turbines developed for the Danish market in the late 1970s proved to be the template for future development. © 2024 Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

Place, publisher, year, edition, pages
Amsterdam: Elsevier, 2024
Keywords
Energy history, wind energy history, wind energy, wind power history, wind power, wind turbine history, wind turbine design
National Category
Energy Engineering
Research subject
Smart Cities and Communities, PROACTS
Identifiers
urn:nbn:se:hh:diva-50256 (URN)10.1016/B978-0-323-93940-9.00004-9 (DOI)2-s2.0-85213180001 (Scopus ID)9780124095489 (ISBN)
Available from: 2023-03-30 Created: 2023-03-30 Last updated: 2025-01-14Bibliographically approved
Möllerström, E., Gipe, P. & Ottermo, F. (2024). Wind power development: A historical review. Wind Engineering: The International Journal of Wind Power
Open this publication in new window or tab >>Wind power development: A historical review
2024 (English)In: Wind Engineering: The International Journal of Wind Power, ISSN 0309-524X, E-ISSN 2048-402XArticle, review/survey (Refereed) Epub ahead of print
Abstract [en]

Wind power only received occasional attention since the introduction of electricity until the 1970s, when a revived interest in alternativeenergy sources spurred the development thread that led to today’s wind turbines. Although attention and financial support at thetime were directed toward government-funded MW-scale wind turbines, the small models developed in the late 1970s for the Danishmarket were ultimately the way forward. The wind industry has since matured, as evidenced by the lower specific power and highercapacity factors of recent turbine models and the similarity between their power curve shapes. Moreover, this study highlights two historicalaccomplishments by Europeans that are sometimes incorrectly credited to Americans: the first wind turbine to generate electricitywas built in 1883 by Austrian Josef Friedländer and the Danish Agricco (1919) became the first public grid-connected windturbine. © The Author(s) 2024

Place, publisher, year, edition, pages
London: Sage Publications, 2024
Keywords
Wind turbine history, wind-electric generators, wind turbine design
National Category
Energy Engineering
Research subject
Smart Cities and Communities, PROACTS
Identifiers
urn:nbn:se:hh:diva-54333 (URN)10.1177/0309524x241260061 (DOI)001275798700001 ()2-s2.0-85199868871 (Scopus ID)
Available from: 2024-07-25 Created: 2024-07-25 Last updated: 2025-01-13Bibliographically approved
Gipe, P. & Möllerström, E. (2023). An overview of the history of wind turbine development: Part II–The 1970s onward. Wind Engineering: The International Journal of Wind Power, 47(1), 220-248
Open this publication in new window or tab >>An overview of the history of wind turbine development: Part II–The 1970s onward
2023 (English)In: Wind Engineering: The International Journal of Wind Power, ISSN 0309-524X, E-ISSN 2048-402X, Vol. 47, no 1, p. 220-248Article, review/survey (Refereed) Published
Abstract [en]

We review the development of wind turbines for generating electricity from the late 19th century to the present, summarizing some key characteristics. We trace the move from two and four blade wind turbines to the three blades common today. We establish that it was not the governmental-funded wind programs with its large-scale prototypes of the 1970–80s that developed into the commercial turbines of today. Instead, it was the small-scale Danish wind turbines, developed for an agricultural market, that developed into the commercial turbines of today. And we show that much of what we know today about wind turbine design was known by the 1930s and certainly well known by the late 1950s. This work is divided into two parts: the first part takes up the development from the first electricity producing wind turbines through to the 1960s and a second part on development from the 1970s onward. © The Author(s) 2022.

Place, publisher, year, edition, pages
London: Sage Publications, 2023
Keywords
Wind turbine history, wind-electric generators, wind turbine design
National Category
Energy Engineering
Identifiers
urn:nbn:se:hh:diva-48027 (URN)10.1177/0309524X221122594 (DOI)000852021100001 ()2-s2.0-85136459336 (Scopus ID)
Available from: 2022-09-08 Created: 2022-09-08 Last updated: 2024-07-29Bibliographically approved
Lind, J., Möllerström, E., Averfalk, H. & Ottermo, F. (2023). Energy flexibility using the thermal mass of residential buildings. Energy and Buildings, 301, 1-12, Article ID 113698.
Open this publication in new window or tab >>Energy flexibility using the thermal mass of residential buildings
2023 (English)In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 301, p. 1-12, article id 113698Article, review/survey (Refereed) Published
Abstract [en]

The transition to a more sustainable energy system with a growing amount of intermittent renewable energy sources brings an increasing need for flexibility measures to maintain balance between supply and demand. Buildings represent a promising source of demand-side flexibility due to their large energy demand and thermal mass. This review provides insights into the storage potential of building thermal mass, and the benefits and challenges it brings. It is found that building thermal mass storage have good ability to shift loads on short term, from peak to off-peak hours. This ability can be utilized for different purposes, for instance reduced costs for end-users or energy providers, reduced primary energy demand, or reduced CO2 emissions. Furthermore, this review explores different factors that influence the storage potential of building thermal mass, with special attention paid to the heat emission system. It is shown that hydronic floor heating is beneficial compared to radiators since it directly can activate the thermal mass with smaller impact on the indoor temperature. It is also found that the factor with largest impact is the envelope insulation level; increased insulation level brings improved storage efficiency and prolonged thermal autonomy but also decreased storage capacity and increased risk of overheating. Finally, research gaps are identified. © 2023 The Authors

Place, publisher, year, edition, pages
Amsterdam: Elsevier, 2023
Keywords
Building thermal mass (BTM), Demand-side management, Energy flexibility, Load shifting, Residential buildings, Thermal energy storage (TES)
National Category
Energy Systems Energy Engineering
Identifiers
urn:nbn:se:hh:diva-52037 (URN)10.1016/j.enbuild.2023.113698 (DOI)2-s2.0-85175613669& (Scopus ID)
Available from: 2023-11-21 Created: 2023-11-21 Last updated: 2023-11-28Bibliographically approved
Sánchez-García, L., Averfalk, H., Möllerström, E. & Persson, U. (2023). Understanding effective width for district heating. Energy, 277, Article ID 127427.
Open this publication in new window or tab >>Understanding effective width for district heating
2023 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 277, article id 127427Article in journal (Refereed) Published
Abstract [en]

District heating is one of the technologies that can contribute to the decarbonisation of the European heat sector. Nonetheless, these infrastructures only deliver about a tenth of the heat demands in the continent. Therefore, it is essential to assess the expansion potential of these systems and to identify which areas should be target for further investigations, which calls for easy-to-use and straightforward methods such as Persson & Werner's network capital cost model. Pivotal parameters of the model are the effective width, a metric of trench length by land area, alongside the average pipe diameter and the linear heat density. This study has carried out an in-depth analysis of these crucial parameters with respect to both distribution and service pipes in a large Danish district heating network, which has allowed to explore the behaviour of effective width in a broad range of building densities and derive new equations for both effective width and average pipe diameter. The model has subsequently been validated in another large network in Denmark and several minor districts in the same country, showing the accuracy of the model on an aggregated level. © 2023 Elsevier Ltd.

Place, publisher, year, edition, pages
London: Elsevier, 2023
Keywords
District heating, GIS, Pipe network, Cost analysis, Effective width, Plot ratio
National Category
Energy Engineering
Research subject
Smart Cities and Communities
Identifiers
urn:nbn:se:hh:diva-50424 (URN)10.1016/j.energy.2023.127427 (DOI)000992994200001 ()2-s2.0-85154565584 (Scopus ID)
Funder
EU, Horizon 2020, 846463
Available from: 2023-05-07 Created: 2023-05-07 Last updated: 2023-06-21Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0001-9982-5317

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