uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Sensitivity of district heating system operation to heat demand reductions and electricity price variations: A Swedish example
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. (Built Environment Energy Systems Group (BEESG))
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Solid State Physics. (Built Environment Energy Systems Group (BEESG))
Optensys Energianalys, Cleantech Park, Linköping.
2012 (English)In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 41, no 1, 525-540 p.Article in journal (Refereed) Published
Abstract [en]

In the future, district heating companies in Sweden must adapt to energy efficiency measures in buildings and variable fuel and electricity prices. Swedish district heating demands are expected to decrease by 1-2% per year and electricity price variations seem to be more unpredictable in the future. A cost-optimisation model of a Swedish local district heating system is constructed using the optimisation modelling tool MODEST. A scenario for heat demand changes due to increased energy efficiency in buildings, combined with the addition of new buildings, is studied along with a sensitivity analysis for electricity price variations. Despite fears that heat demand reductions will decrease co-generation of clean electricity and cause increased global emissions, the results show that anticipated heat demand changes do not increase the studied system's primary energy use or global CO2 emissions. The results further indicate that the heat production plants and the fuels used within the system have crucial importance for the environmental impact of district heat use. Results also show that low seasonal variations in electricity price levels with relatively low winter prices promote the use of electric heat pumps. High winter prices on the other hand promote co-generation of heat and electricity in CHP plants.

Place, publisher, year, edition, pages
2012. Vol. 41, no 1, 525-540 p.
Keyword [en]
District heating, CHP, Building energy efficiency, CO2 emissions, Primary energy use, Electricity price variations
National Category
Engineering and Technology
Research subject
Engineering Science
Identifiers
URN: urn:nbn:se:uu:diva-175624DOI: 10.1016/j.energy.2012.02.034ISI: 000304076800058OAI: oai:DiVA.org:uu-175624DiVA: diva2:532735
Available from: 2012-06-12 Created: 2012-06-11 Last updated: 2017-12-07Bibliographically approved
In thesis
1. District Heating Sensitivity to Heat Demand Reductions and Electricity Market Dynamics
Open this publication in new window or tab >>District Heating Sensitivity to Heat Demand Reductions and Electricity Market Dynamics
2012 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

Sweden and the rest of the EU member states have to reduce primary energy use andemissions of CO2, and increase the use of renewable energy sources according to the EUclimate change package “20-20-20”. To do this, the energy systems need to use less fossilfuel and to utilise energy resources more efficiently. Reduction of energy use in buildings isan important part of this transformation. In Sweden, district heating is the most commontechnique to supply heat for space heating and domestic hot water to multi-family residentialbuildings in urban areas. Efficiency improvements in buildings connected to district heatingsystems should not be counterproductive from a systems perspective, e.g. causing lessefficient total use of resources and increased global CO2 emissions. A reduced electricityproduction in combined heat and power plants, which may be a result of reduced districtheating demand, is sometimes seen as problematic with regards to emissions of CO2, sincethis electricity is normally considered to replace electricity produced in less efficient fossilfuelledcondensing power plants.This licentiate thesis summarises the first part of a PhD project that studies thepossibilities for Swedish district heating systems to adapt to a reduced demand for heating inbuildings, as well as to changes in energy markets. In this thesis the impact of buildingenergy-efficiency improvements and electricity market dynamics on the operation of districtheating systems and CO2 emissions is investigated.The energy system cost-optimisation software MODEST has been used to study theimpact of heat demand changes on the heat and electricity production in the Swedish districtheating systems in Linköping and Uppsala. MODEST optimisations were also used toinvestigate the impact of electricity price fluctuations on the operation of the Uppsaladistrict heating system, and the interaction between the national power system and allSwedish district heating systems collectively.The results show that energy efficiency improvements in buildings that reduce heatdemand by up to 40 % do not increase global CO2 emissions due to production of districtheating. This is because heat-only production is reduced to a larger extent than combinedheat and power production. The results also show that low electricity prices during winterand a large introduction of intermittent wind and solar power generation in the Swedishpower system can be expected to induce use of electricity for district heat production and tohamper co-generation of electricity in combined heat and power plants.

Place, publisher, year, edition, pages
Uppsala universitet, 2012. 68 p.
National Category
Energy Systems
Research subject
Engineering Science
Identifiers
urn:nbn:se:uu:diva-176407 (URN)
Presentation
2012-01-16, Å2002, Lägerhyddsvägen 1, Uppsala, 13:15 (Swedish)
Opponent
Supervisors
Available from: 2012-06-27 Created: 2012-06-19 Last updated: 2012-06-27Bibliographically approved
2. System Effects of Improved Energy Efficiency in Swedish District-Heated Buildings
Open this publication in new window or tab >>System Effects of Improved Energy Efficiency in Swedish District-Heated Buildings
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

To alleviate global warming, European-Union member states must reduce primary energy use, emit less carbon dioxide (CO2), and increase renewable energy use. Buildings constitute a great potential for energy savings, but saving energy in district-heated buildings influences combined heat and power (CHP) production, other electricity generation, and global CO2 emissions.

 

This thesis investigates the system effects from Swedish district heating production caused by district heating demand changes due to energy conservation in buildings. The cost-optimising linear programming modelling tools MODEST and FMS, the latter developed in the context of this thesis, are used to describe present district heating production and to investigate the impact of heat-demand reductions in twelve Swedish district heating systems, four of them representing all Swedish district heating.

 

Energy savings in district-heated, multi-family residential buildings yield a lower, more seasonally levelled district heating demand. These demand changes mainly reduce use of fossil-fuel and biomass for heat production. CHP production is significantly reduced if it supplies intermediate or peak district heating load. The αsystem value (ratio between generated CHP electricity and produced district heating) increases by demand reductions if CHP mainly supplies base district heating load. CO2 emissions due to district heat production depend on the approach used for CO2 assessment of electricity, and are generally reduced with heat demand reductions, unless the share of CHP production is large and the reduced fuel use yields smaller emission reductions than the emission increase from power production that replaces reduced CHP generation.

 

In total, heat demand reductions reduce CO2 emissions due to Swedish district heating, and the district heating systems even constitute a carbon sink at certain energy conservation levels. If saved biomass replaces fossil fuels elsewhere, a lower heat demand reduces CO2 emissions for every studied district heating system.

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2014. 91 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1161
Keyword
district heating, carbon dioxide emissions, building energy efficiency, combined heat and power
National Category
Energy Systems
Research subject
Engineering Science
Identifiers
urn:nbn:se:uu:diva-229477 (URN)978-91-554-8996-0 (ISBN)
Public defence
2014-09-26, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 13:15 (English)
Opponent
Supervisors
Funder
Swedish Energy Agency
Available from: 2014-09-17 Created: 2014-08-08 Last updated: 2017-01-19

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Åberg, MagnusWidén, Joakim

Search in DiVA

By author/editor
Åberg, MagnusWidén, Joakim
By organisation
Solid State Physics
In the same journal
Energy
Engineering and Technology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 985 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf