Transition towards carbon neutral district heating by utilising low-temperature heat

Pauli Hiltunen

Transition towards carbon neutral district heating by utilising low-temperature heat

Julkaisun otsikon käännös: Siirtymä hiilineutraaliin kaukolämpöön hyödyntämällä matala lämpötilaista lämpöä

Pauli Hiltunen

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Lämmitys- ja jäähdytyssektorin energiankulutus kattaa yli puolet Euroopan unionin kokonaiskulutuksesta. Tästä syystä lämmityksen päästöjen vähentäminen on erityisen tärkeää, jotta ilmastonmuutosta saataisiin hillittyä ja päästäisiin EU:n ilmastotavoitteisiin. Lisäksi vuonna 2022 alkanut Ukrainan sota on lisännyt entisestään paineita vähentää riippuvuutta fossiilisista polttoaineista energiantuotannossa. Vanhan olemassa olevan infrastruktuurin muuttaminen hiilineutraaliksi saattaa kestää vuosikymmeniä, ja muutos todennäköisesti tapahtuu askel kerrallaan. Tässä väitöskirjassa tutkittiin Espoon kaukolämmön siirtymää hiilineutraaliin tuotantoon. Erityisesti tutkittiin Espooseen suunnitellun datakeskuksen hukkalämmön käytön roolia siirtymässä ja sähköistetyn kaukolämmön tuotannon mahdollisuuksia selvitä sähkön hinnan noususta. Väitöskirjassa tutkittiin myös kaukolämmön paluuveden sisältämän lämmön hyödyntämistä Tallinnan teknillisen yliopiston kampuksen lämmityksessä. Kaukolämpöverkon paluuvettä voidaan hyödyntää uusilla ja kunnostetuilla alueilla, joissa rakennusten lämmitysjärjestelmät soveltuvat matalammille lämpötiloille. Ratkaisua on tutkittu yhtenä vaihtoehtona siirtymäajalle matalan lämpötilan kaukolämpöverkkoihin. Paluuveden lämmön hyödyntäminen laskee paluulämpötilaa koko kaukolämpöverkossa, mikä puolestaan vähentää lämpöhäviöitä ja parantaa energiantuotannon hyötysuhdetta. Kaukolämmön tuotannon sähköistäminen vähentää polttoaineiden kulutusta ja voi auttaa tasapainottamaan sähkömarkkinoita, joissa on suuri osuus vaihtelevaa tuotantoa kuten tuuli- tai aurinkovoimaa. Lisäksi yhteiskunnan digitalisoituminen lisää IT-sektorin jo ennestään suurta energiantarvetta. Datakeskusten jäähdytys tuottaa suuria määriä hukkalämpöä, mitä voidaan hyödyntää kaukolämmön tuotannossa. Tämän väitöskirjan tulokset osoittavat, että kaukolämpö on ympäristöystävällinen vaihtoehto maakaasulla lämmitetylle kampukselle vähentäen hiilidioksidipäästöjä ja primäärienergian kulutusta. Hyödyntämällä kaupungin kaukolämpöverkon paluuveden lämpöä kampuksen lämmityksessä päästöjä ja primäärienergian kulutusta voidaan vähentää vielä enemmän, ja kaukolämpöjärjestelmän sähkön- ja lämmöntuotannon hyötysuhteet paranevat. Datakeskusten hukkalämpö tarjoaa taloudellisesti kannattavan vaihtoehdon fossiilisille polttoaineille perustehon tuotantoon, mutta hukkalämpökuorman ja lämmönkulutuksen epäsuhdan takia huipputehon saavuttaminen hukkalämmön avulla on vaikeaa. Koska datakeskusten hukkalämmön lämpötilaa pitää nostaa lämpöpumpuilla, sähkön hinnalla on suuri merkitys hukkalämmön kannattavuuteen. Toisaalta lämpöpumput osoittautuivat olevan kannattavia korkeillakin sähkönhinnoilla, jos polttoaineiden hinnat ovat myös korkealla, kuten loppuvuonna 2021 tapahtui.

Julkaisun otsikon käännös	Siirtymä hiilineutraaliin kaukolämpöön hyödyntämällä matala lämpötilaista lämpöä
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Syri, Sanna, Vastuuprofessori Syri, Sanna, Ohjaaja Volkova, Anna, Ohjaaja, Ulkoinen henkilö
Kustantaja	Aalto University
Painoksen ISBN	978-952-64-1749-3
Sähköinen ISBN	978-952-64-1750-9
Tila	Julkaistu - 2024
OKM-julkaisutyyppi	G5 Artikkeliväitöskirja

Tutkimusalat

kaukolämpö
lämpöpumput
hukkalämpö
datakeskukset
energiatehokkuus

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http://urn.fi/URN:ISBN:978-952-64-1750-9

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@phdthesis{e94616e42e034b7499cd95bb2892ac9e,

title = "Transition towards carbon neutral district heating by utilising low-temperature heat",

abstract = "Heating and cooling sector accounts for more than half of the total energy demand in European Union. Traditionally, fossil fuels have had a large share in producing heat to buildings and domestic hot water. Therefore, to mitigate the climate change and achieve European Union's climate goals, decarbonisation of the sector is essential. The war in Ukraine and energy crisis in 2022 increased the pressure to reduce the dependency of imported fossil fuels in heating even more. The transition of old infrastructure to low-carbon heat sources will take decades and will likely happen step-by-step. In this thesis, the transition to carbon-neutral production in Espoo district heating system was investigated. Especially, the role of low-temperature waste heat from the data centres in Espoo during the transition and feasibility of electrified district heating during electricity price shocks were studied. Utilising heat from district heating network's return water to provide heating and improve the energy efficiency were investigated in the campus of Tallinn Technical University was studied in this thesis as well. Utilising the return water of district heating in low-temperature energy cascades has been discussed as an option to reduce distribution losses in newly built or refurbished areas during the transition to low-temperature district heating. Use of heat from return water reduces the return temperature of the district heating network, which has a positive impact on the energy efficiency of the entire system. Electrification of district heating reduces the consumption of combustible fuels and can help balancing the electricity markets with high share of intermittent power production such as wind or solar power. Furthermore, digitalisation of the society will increase the already high energy demand of IT sector. Cooling of data centres produces large quantities of waste heat, which can be utilised in district heating. The results of this thesis show that district heating can provide environmentally sustainable alternative to the university campus heated by a natural gas-fired boiler reducing carbon emissions and primary energy consumption. Implementing a sub-network utilising low-temperature heat from the city's district heating network could reduce the emissions and primary energy consumption even more by lowering the heat losses and improving the efficiency of power and heat production in the combined heat-and-power plants. Waste heat from data centres can provide economical heat source for base load production in district heating systems, but it suits poorly for peak demand production during the heating season due to the mismatch between waste heat load and heat demand. Increasing electricity price hinders the profitability of heat pumps priming the low-temperature waste heat. However, heat pumps proved to produce economically viable heat even with high electricity prices, if the costs of fossil fuels are high as well, as it happened in 2021.",

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author = "Pauli Hiltunen",

year = "2024",

language = "English",

isbn = "978-952-64-1749-3",

series = "Aalto University publication series DOCTORAL THESES",

publisher = "Aalto University",

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TY - BOOK

T1 - Transition towards carbon neutral district heating by utilising low-temperature heat

AU - Hiltunen, Pauli

PY - 2024

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N2 - Heating and cooling sector accounts for more than half of the total energy demand in European Union. Traditionally, fossil fuels have had a large share in producing heat to buildings and domestic hot water. Therefore, to mitigate the climate change and achieve European Union's climate goals, decarbonisation of the sector is essential. The war in Ukraine and energy crisis in 2022 increased the pressure to reduce the dependency of imported fossil fuels in heating even more. The transition of old infrastructure to low-carbon heat sources will take decades and will likely happen step-by-step. In this thesis, the transition to carbon-neutral production in Espoo district heating system was investigated. Especially, the role of low-temperature waste heat from the data centres in Espoo during the transition and feasibility of electrified district heating during electricity price shocks were studied. Utilising heat from district heating network's return water to provide heating and improve the energy efficiency were investigated in the campus of Tallinn Technical University was studied in this thesis as well. Utilising the return water of district heating in low-temperature energy cascades has been discussed as an option to reduce distribution losses in newly built or refurbished areas during the transition to low-temperature district heating. Use of heat from return water reduces the return temperature of the district heating network, which has a positive impact on the energy efficiency of the entire system. Electrification of district heating reduces the consumption of combustible fuels and can help balancing the electricity markets with high share of intermittent power production such as wind or solar power. Furthermore, digitalisation of the society will increase the already high energy demand of IT sector. Cooling of data centres produces large quantities of waste heat, which can be utilised in district heating. The results of this thesis show that district heating can provide environmentally sustainable alternative to the university campus heated by a natural gas-fired boiler reducing carbon emissions and primary energy consumption. Implementing a sub-network utilising low-temperature heat from the city's district heating network could reduce the emissions and primary energy consumption even more by lowering the heat losses and improving the efficiency of power and heat production in the combined heat-and-power plants. Waste heat from data centres can provide economical heat source for base load production in district heating systems, but it suits poorly for peak demand production during the heating season due to the mismatch between waste heat load and heat demand. Increasing electricity price hinders the profitability of heat pumps priming the low-temperature waste heat. However, heat pumps proved to produce economically viable heat even with high electricity prices, if the costs of fossil fuels are high as well, as it happened in 2021.

AB - Heating and cooling sector accounts for more than half of the total energy demand in European Union. Traditionally, fossil fuels have had a large share in producing heat to buildings and domestic hot water. Therefore, to mitigate the climate change and achieve European Union's climate goals, decarbonisation of the sector is essential. The war in Ukraine and energy crisis in 2022 increased the pressure to reduce the dependency of imported fossil fuels in heating even more. The transition of old infrastructure to low-carbon heat sources will take decades and will likely happen step-by-step. In this thesis, the transition to carbon-neutral production in Espoo district heating system was investigated. Especially, the role of low-temperature waste heat from the data centres in Espoo during the transition and feasibility of electrified district heating during electricity price shocks were studied. Utilising heat from district heating network's return water to provide heating and improve the energy efficiency were investigated in the campus of Tallinn Technical University was studied in this thesis as well. Utilising the return water of district heating in low-temperature energy cascades has been discussed as an option to reduce distribution losses in newly built or refurbished areas during the transition to low-temperature district heating. Use of heat from return water reduces the return temperature of the district heating network, which has a positive impact on the energy efficiency of the entire system. Electrification of district heating reduces the consumption of combustible fuels and can help balancing the electricity markets with high share of intermittent power production such as wind or solar power. Furthermore, digitalisation of the society will increase the already high energy demand of IT sector. Cooling of data centres produces large quantities of waste heat, which can be utilised in district heating. The results of this thesis show that district heating can provide environmentally sustainable alternative to the university campus heated by a natural gas-fired boiler reducing carbon emissions and primary energy consumption. Implementing a sub-network utilising low-temperature heat from the city's district heating network could reduce the emissions and primary energy consumption even more by lowering the heat losses and improving the efficiency of power and heat production in the combined heat-and-power plants. Waste heat from data centres can provide economical heat source for base load production in district heating systems, but it suits poorly for peak demand production during the heating season due to the mismatch between waste heat load and heat demand. Increasing electricity price hinders the profitability of heat pumps priming the low-temperature waste heat. However, heat pumps proved to produce economically viable heat even with high electricity prices, if the costs of fossil fuels are high as well, as it happened in 2021.

KW - district heating

KW - heat pumps

KW - waste heat

KW - data centre

KW - heat efficiency

KW - kaukolämpö

KW - lämpöpumput

KW - hukkalämpö

KW - datakeskukset

KW - energiatehokkuus

KW - district heating

KW - heat pumps

KW - waste heat

KW - data centre

KW - heat efficiency

M3 - Doctoral Thesis

SN - 978-952-64-1749-3

T3 - Aalto University publication series DOCTORAL THESES

PB - Aalto University

ER -

Transition towards carbon neutral district heating by utilising low-temperature heat

Abstrakti

Tutkimusalat

YK:n kestävän kehityksen tavoitteet

Pääsy asiakirjaan

Sormenjälki

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