Fuel cells and electrolysers in future energy systems

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

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Resumé

Effektive brændselsceller og elektrolysesystemer er stadigvæk på udviklingsstadiet. I denne Ph.d.‐afhandling analyseres fremtidens brændselsceller og elektrolyseanlæg i fremtidige vedvarende energisystemer. Forbrændingsteknologier dækker i dag størstedelen af elektri‐ citets‐, varme‐ og transportbehovet. Sammenlignet med disse traditionelle teknologier har brændselsceller en højere nyttevirkning. Der findes dog typer af energisystemer, hvor brændselsbesparelsen går tabt i teknologier andre steder i systemet.

Udgangspunktet for denne Ph.d.‐afhandling er, at de forbedringer, der opnås ved at indføre brændselsceller, afhænger af energisystemets specifikke design og reguleringsmuligheder. Af samme årsag tilfører nogle brændselsceller mere værdi til energisystemet end andre. I afhandlingen præsenteres der både energisystemer, hvor brændselsceller opnår synergief‐ fekter med andre komponenter i energisystemet, og energisystemer, hvor brændselscel‐ lens højere nyttevirkning går tabt i andre dele af systemet.

For at kunne identificere passende anvendelsesmuligheder for brændselsceller og elektro‐ lyseanlæg i fremtidige energisystemer, skal der tages hensyn til, i hvilken retning energisy‐ stemerne udvikler sig. I denne Ph.d.‐afhandling analyseres brændselsceller i forbindelse med energisystemer, der gradvist ændres fra det nuværende design, med store mængder fossile forbrændingsteknologier, til et fremtidigt design, der er baseret på 100% vedvaren‐ de energi. Brændselsceller og elektrolyseanlæg er analyseret i disse fremtidige vedvarende energisystemer, og konklusionerne skal derfor ses i denne kontekst.

I fremtidige energisystemer er der en risiko for, at de højere nyttevirkninger, der opnås ved hjælp af brændselsceller, går tabt, fordi systemet ikke er udrustet til at udnytte brændsels‐ cellernes fulde potentiale. Hvis brændselsceller erstatter gasturbiner i kraftvarmeværker, kan disse forbedringer gå tabt, fordi en større del af varmebehovet nu skal dækkes af ked‐ ler. I integrerede energisystemer kan den lavere varmeproduktion fra brændselscellekraft‐ varme erstattes af varme fra varmepumper i stedet for varme fra kedler ved brug af var‐ melagre. Dette giver en synergi mellem brændselsceller og varmepumper, hvor det fulde potentiale af brændselscellerne kan udnyttes. I integrerede energisystemer med større mængder fluktuerende vedvarende energi giver brændselsceller større brændselsbesparel‐ ser end i traditionelle energisystemer. De er derfor vigtige skridt på vejen mod fremtidige 100% vedvarende energisystemer.

Brugen af brændselsceller i decentrale kraftvarmeværker i stedet for gasturbiner ser særligt lovende ud, fordi brændselscellerne har en højere nyttevirkning i både fuldlast og dellast. Brændselsceller bør ikke udvikles til grundlastværker men derimod til fleksible regulerbare værker i energisystemer med store mængder fluktuerende vedvarende energi og kraftvar‐ me. Grundlastværker er ikke nødvendige i disse energisystemer. Med disse egenskaber kan
brændselscellerne erstatte kondenskraftværker. Der kan opnås en synergi ved at bruge brændselsceller i vedvarende energisystemer, fordi antallet af driftstimer mindskes og brændselscellernes levetid bliver mindre afgørende.

Brintbaserede mikrokraftvarmeanlæg med brændselsceller i individuelle husstande er ikke egnede til vedvarende energisystemer på grund af store tab i omdannelsen til hydrogen samt lavere reguleringsmuligheder i sådanne systemer. På kort sigt kan naturgasbaserede brændselsceller i mikrokraftvarmeanlæg udbrede kraftvarmeproduktionen, udover hvad der kan lade sig gøre med decentrale brændselscellekraftvarmeværker. Dette kan potenti‐ elt set øge effektiviteten af energisystemet og erstatte produktionen på kulkraftværker, men der er en risiko for, at produktionen på mere effektive brændselscellekraftvarmevær‐ ker dermed bliver fortrængt. På lang sigt bør det dog overvejes, hvilke brændselstyper mi‐ krokraftvarmeanlæg kan anvende, og hvordan brændslet kan distribueres. Naturgas vil kun i begrænset omfang være til stede i fremtidige vedvarende energisystemer og efterspørgs‐ len på brændstof i gasform, såsom biogas og syngas, vil stige betydeligt. Brændselscelle‐ kraftvarmeværker udgør derfor en mere brændselseffektiv mulighed for at udnytte disse knappe ressourcer. Varmepumper er en bedre opvarmningsform i individuelle husstande, da de er mere brændselseffektive og er forbundet med lavere omkostninger.

Både brændselscellebiler og batteridrevne elbiler har en højere nyttevirkning end køretøjer med traditionelle forbrændingsmotorer. I et fremtidigt vedvarende energisystem er elbiler mere egnede til transport end brændselscellebiler. Rækkevidden for elbiler kan dog være et problem i forhold til en del af transportbehovet. Her kan hybridbiler med både brændsels‐ celler og batterier kombinere de to teknologiers høje nyttevirkning og øge rækkevidden. Hybridbiler er ikke analyseret i denne afhandling.

På kort sigt er brint fra elektrolyseanlæg en unødvendig løsning, og på lang sigt er visse an‐ vendelser mere egnede end andre. Andre energilagringsteknologier, som f.eks. store var‐ mepumper på kraftvarmeværker samt elbiler, bør indføres som de første, fordi disse tekno‐ logier er mere brændselseffektive og har væsentlig lavere omkostninger. Elektrolyseanlæg bør kun implementeres i energisystemer med store mængder fluktuerende vedvarende energi og kraftvarme. De udgør dog en vigtig del af 100% vedvarende energisystemer, fordi de kan erstatte biobrændsler. I disse systemer bør elektrolyseanlæg udvikles til at have størst mulige nyttevirkning, mest fleksible reguleringsmuligheder og lavest mulige omkostninger.
OriginalsprogEngelsk
Udgivelses stedAalborg
ForlagInstitut for Samfundsudvikling og Planlægning, Aalborg Universitet
Antal sider328
ISBN (Trykt)978-87-91830-26-6
StatusUdgivet - 2008
NavnISP-Skriftserie
Nummer2008-19

Fingerprint

Fuel cells
Cogeneration plants
Fuel cell power plants
Pumps
Hydrogen
Gas turbines
Boilers
Natural gas
Hot Temperature
Systems analysis
Electric batteries
Heat storage
Hydrogen fuels
District heating
Biogas
Hybrid vehicles

Citer dette

Mathiesen, B. V. (2008). Fuel cells and electrolysers in future energy systems. Aalborg: Institut for Samfundsudvikling og Planlægning, Aalborg Universitet. ISP-Skriftserie, Nr. 2008-19
Mathiesen, Brian Vad. / Fuel cells and electrolysers in future energy systems. Aalborg : Institut for Samfundsudvikling og Planlægning, Aalborg Universitet, 2008. 328 s. (ISP-Skriftserie; Nr. 2008-19).
@phdthesis{61cac970cd1511dda016000ea68e967b,
title = "Fuel cells and electrolysers in future energy systems",
abstract = "Efficient fuel cells and electrolysers are still at the development stage. In this dissertation, future developed fuel cells and electrolysers are analysed in future renewable energy sys‐ tems. Today, most electricity, heat and transport demands are met by combustion tech‐ nologies. Compared to these conventional technologies, fuel cells have the ability to signifi‐ cantly increase the efficiency of the system while meeting such demands. However, energy system designs can be identified in which the fuel savings achieved are lost in technologies elsewhere in the system.This dissertation is based on the fact that the improvements obtained by implementing fuel cells depend on the specific design and regulation possibilities of the energy system in which they are used. For the same reason, some applications of fuel cells add more value to the system than others. Energy systems have been identified, both in which fuel cell appli‐ cations create synergy effects with other components of the system, as well as in which the efficiency improvements achieved by using fuel cells are lost elsewhere in the system.In order to identify suitable applications of fuel cells and electrolysers in future energy sys‐ tems, the direction in which these systems develop must be considered. In this dissertation, fuel cells are analysed in the context of energy systems that are gradually changing from the current design, with large amounts of fossil fuel combustion technologies, to a future design based on 100 per cent renewable energy. The conclusions of the analyses refer to the application of fuel cells and electrolysers to such future renewable energy systems and should thus be seen in this context.In future energy systems, there is a risk that improvements in efficiency are lost, because the system design is not equipped for utilising the full potential of fuel cells. If fuel cells re‐ place gas turbines in combined heat and power (CHP) plants, the improvements may be lost, because a larger part of the heat demand must now be met by boilers. In integrated energy systems with large heat pumps, however, the decreased heat production from fuel cells at CHP plants can be met by heat pumps instead of by boilers using heat storages. In such applications, a synergy is created between the components of the system and the full potential of the fuel cells is utilised. Fuel cells induce higher fuel savings in integrated en‐ ergy systems with large shares of intermittent renewable energy than in conventional en‐ ergy systems. Thus, they are important measures on the path towards future 100 per cent renewable energy systems.In locally distributed CHP plants with district heating grids, fuel cells are especially promis‐ ing in terms of replacing conventional gas turbines. Fuel cells have higher efficiencies than these, also in part load. Fuel cells should not be developed for base load operation, but for flexible regulation in energy systems with large amounts of intermittent renewable energy and CHP plants. Base load plants are not required in such energy systems. With such abili‐ties fuel cells can replace steam turbines. Synergy can be created by using fuel cells in re‐ newable energy systems, because the number of operation hours decreases and the life‐ time of the cells becomes less significant.Hydrogen micro‐fuel cell CHPs in individual households are not suitable for renewable en‐ ergy systems. This is due to the high losses associated with the conversion to hydrogen and the lower regulation abilities of such systems. In a short‐term perspective, natural gas mi‐ cro‐fuel cell CHP may spread the CHP production more than locally distributed fuel cell CHPs are capable of doing. This can potentially increase the efficiency of the energy system and displace the production at coal‐fired power plants; however, there is a risk that the production at more efficient fuel cell CHP plants is displaced. In the long term, however, it should be considered which fuels such technologies can utilise and how these fuels can be distributed. Natural gas is not an option in future renewable energy systems and the de‐ mand for gaseous fuels, such as biogas or syngas, will increase significantly. Hence, fuel cell CHP plants represent a more fuel‐efficient option in terms of using such scarce resources. Heat pumps are more fuel and cost‐efficient options in terms of meeting the heat demand in individual houses.Both fuel cell and battery electric vehicles are more efficient options than conventional internal combustion engine vehicles. In terms of transport, battery electric vehicles are more suitable than hydrogen fuel cell vehicles in future energy system. Battery electric ve‐ hicles may, for a part of the transport demand, have limitations in their range. Hybrid tech‐ nologies may provide a good option, which can combine the high fuel efficiency of battery electric vehicles with efficient fuel cells in order to increase the range. Such hybrid vehicles have not been investigated in this dissertation.In the short term, electrolyser hydrogen is not suitable for fuel cell applications; and in the long term, some applications of electrolysers are more suitable than others. Other energy storage technologies, such as large heat pumps in CHP plants and battery electric vehicles, should be implemented first, because these technologies are more fuel and cost‐efficient. Electrolysers should only be implemented in energy systems with very high shares of in‐ termittent renewable energy and CHP; but in a 100 per cent renewable energy system, they constitute a key part, because they displace fuels derived from biomass. In such applica‐ tions, electrolysers should be developed to have the highest possible efficiency, the most flexible regulation abilities, and the lowest investment costs possible.",
author = "Mathiesen, {Brian Vad}",
year = "2008",
language = "English",
isbn = "978-87-91830-26-6",
publisher = "Institut for Samfundsudvikling og Planl{\ae}gning, Aalborg Universitet",

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Mathiesen, BV 2008, Fuel cells and electrolysers in future energy systems. ISP-Skriftserie, nr. 2008-19, Institut for Samfundsudvikling og Planlægning, Aalborg Universitet, Aalborg.

Fuel cells and electrolysers in future energy systems. / Mathiesen, Brian Vad.

Aalborg : Institut for Samfundsudvikling og Planlægning, Aalborg Universitet, 2008. 328 s. (ISP-Skriftserie; Nr. 2008-19).

Publikation: Bog/antologi/afhandling/rapportPh.d.-afhandlingForskning

TY - BOOK

T1 - Fuel cells and electrolysers in future energy systems

AU - Mathiesen, Brian Vad

PY - 2008

Y1 - 2008

N2 - Efficient fuel cells and electrolysers are still at the development stage. In this dissertation, future developed fuel cells and electrolysers are analysed in future renewable energy sys‐ tems. Today, most electricity, heat and transport demands are met by combustion tech‐ nologies. Compared to these conventional technologies, fuel cells have the ability to signifi‐ cantly increase the efficiency of the system while meeting such demands. However, energy system designs can be identified in which the fuel savings achieved are lost in technologies elsewhere in the system.This dissertation is based on the fact that the improvements obtained by implementing fuel cells depend on the specific design and regulation possibilities of the energy system in which they are used. For the same reason, some applications of fuel cells add more value to the system than others. Energy systems have been identified, both in which fuel cell appli‐ cations create synergy effects with other components of the system, as well as in which the efficiency improvements achieved by using fuel cells are lost elsewhere in the system.In order to identify suitable applications of fuel cells and electrolysers in future energy sys‐ tems, the direction in which these systems develop must be considered. In this dissertation, fuel cells are analysed in the context of energy systems that are gradually changing from the current design, with large amounts of fossil fuel combustion technologies, to a future design based on 100 per cent renewable energy. The conclusions of the analyses refer to the application of fuel cells and electrolysers to such future renewable energy systems and should thus be seen in this context.In future energy systems, there is a risk that improvements in efficiency are lost, because the system design is not equipped for utilising the full potential of fuel cells. If fuel cells re‐ place gas turbines in combined heat and power (CHP) plants, the improvements may be lost, because a larger part of the heat demand must now be met by boilers. In integrated energy systems with large heat pumps, however, the decreased heat production from fuel cells at CHP plants can be met by heat pumps instead of by boilers using heat storages. In such applications, a synergy is created between the components of the system and the full potential of the fuel cells is utilised. Fuel cells induce higher fuel savings in integrated en‐ ergy systems with large shares of intermittent renewable energy than in conventional en‐ ergy systems. Thus, they are important measures on the path towards future 100 per cent renewable energy systems.In locally distributed CHP plants with district heating grids, fuel cells are especially promis‐ ing in terms of replacing conventional gas turbines. Fuel cells have higher efficiencies than these, also in part load. Fuel cells should not be developed for base load operation, but for flexible regulation in energy systems with large amounts of intermittent renewable energy and CHP plants. Base load plants are not required in such energy systems. With such abili‐ties fuel cells can replace steam turbines. Synergy can be created by using fuel cells in re‐ newable energy systems, because the number of operation hours decreases and the life‐ time of the cells becomes less significant.Hydrogen micro‐fuel cell CHPs in individual households are not suitable for renewable en‐ ergy systems. This is due to the high losses associated with the conversion to hydrogen and the lower regulation abilities of such systems. In a short‐term perspective, natural gas mi‐ cro‐fuel cell CHP may spread the CHP production more than locally distributed fuel cell CHPs are capable of doing. This can potentially increase the efficiency of the energy system and displace the production at coal‐fired power plants; however, there is a risk that the production at more efficient fuel cell CHP plants is displaced. In the long term, however, it should be considered which fuels such technologies can utilise and how these fuels can be distributed. Natural gas is not an option in future renewable energy systems and the de‐ mand for gaseous fuels, such as biogas or syngas, will increase significantly. Hence, fuel cell CHP plants represent a more fuel‐efficient option in terms of using such scarce resources. Heat pumps are more fuel and cost‐efficient options in terms of meeting the heat demand in individual houses.Both fuel cell and battery electric vehicles are more efficient options than conventional internal combustion engine vehicles. In terms of transport, battery electric vehicles are more suitable than hydrogen fuel cell vehicles in future energy system. Battery electric ve‐ hicles may, for a part of the transport demand, have limitations in their range. Hybrid tech‐ nologies may provide a good option, which can combine the high fuel efficiency of battery electric vehicles with efficient fuel cells in order to increase the range. Such hybrid vehicles have not been investigated in this dissertation.In the short term, electrolyser hydrogen is not suitable for fuel cell applications; and in the long term, some applications of electrolysers are more suitable than others. Other energy storage technologies, such as large heat pumps in CHP plants and battery electric vehicles, should be implemented first, because these technologies are more fuel and cost‐efficient. Electrolysers should only be implemented in energy systems with very high shares of in‐ termittent renewable energy and CHP; but in a 100 per cent renewable energy system, they constitute a key part, because they displace fuels derived from biomass. In such applica‐ tions, electrolysers should be developed to have the highest possible efficiency, the most flexible regulation abilities, and the lowest investment costs possible.

AB - Efficient fuel cells and electrolysers are still at the development stage. In this dissertation, future developed fuel cells and electrolysers are analysed in future renewable energy sys‐ tems. Today, most electricity, heat and transport demands are met by combustion tech‐ nologies. Compared to these conventional technologies, fuel cells have the ability to signifi‐ cantly increase the efficiency of the system while meeting such demands. However, energy system designs can be identified in which the fuel savings achieved are lost in technologies elsewhere in the system.This dissertation is based on the fact that the improvements obtained by implementing fuel cells depend on the specific design and regulation possibilities of the energy system in which they are used. For the same reason, some applications of fuel cells add more value to the system than others. Energy systems have been identified, both in which fuel cell appli‐ cations create synergy effects with other components of the system, as well as in which the efficiency improvements achieved by using fuel cells are lost elsewhere in the system.In order to identify suitable applications of fuel cells and electrolysers in future energy sys‐ tems, the direction in which these systems develop must be considered. In this dissertation, fuel cells are analysed in the context of energy systems that are gradually changing from the current design, with large amounts of fossil fuel combustion technologies, to a future design based on 100 per cent renewable energy. The conclusions of the analyses refer to the application of fuel cells and electrolysers to such future renewable energy systems and should thus be seen in this context.In future energy systems, there is a risk that improvements in efficiency are lost, because the system design is not equipped for utilising the full potential of fuel cells. If fuel cells re‐ place gas turbines in combined heat and power (CHP) plants, the improvements may be lost, because a larger part of the heat demand must now be met by boilers. In integrated energy systems with large heat pumps, however, the decreased heat production from fuel cells at CHP plants can be met by heat pumps instead of by boilers using heat storages. In such applications, a synergy is created between the components of the system and the full potential of the fuel cells is utilised. Fuel cells induce higher fuel savings in integrated en‐ ergy systems with large shares of intermittent renewable energy than in conventional en‐ ergy systems. Thus, they are important measures on the path towards future 100 per cent renewable energy systems.In locally distributed CHP plants with district heating grids, fuel cells are especially promis‐ ing in terms of replacing conventional gas turbines. Fuel cells have higher efficiencies than these, also in part load. Fuel cells should not be developed for base load operation, but for flexible regulation in energy systems with large amounts of intermittent renewable energy and CHP plants. Base load plants are not required in such energy systems. With such abili‐ties fuel cells can replace steam turbines. Synergy can be created by using fuel cells in re‐ newable energy systems, because the number of operation hours decreases and the life‐ time of the cells becomes less significant.Hydrogen micro‐fuel cell CHPs in individual households are not suitable for renewable en‐ ergy systems. This is due to the high losses associated with the conversion to hydrogen and the lower regulation abilities of such systems. In a short‐term perspective, natural gas mi‐ cro‐fuel cell CHP may spread the CHP production more than locally distributed fuel cell CHPs are capable of doing. This can potentially increase the efficiency of the energy system and displace the production at coal‐fired power plants; however, there is a risk that the production at more efficient fuel cell CHP plants is displaced. In the long term, however, it should be considered which fuels such technologies can utilise and how these fuels can be distributed. Natural gas is not an option in future renewable energy systems and the de‐ mand for gaseous fuels, such as biogas or syngas, will increase significantly. Hence, fuel cell CHP plants represent a more fuel‐efficient option in terms of using such scarce resources. Heat pumps are more fuel and cost‐efficient options in terms of meeting the heat demand in individual houses.Both fuel cell and battery electric vehicles are more efficient options than conventional internal combustion engine vehicles. In terms of transport, battery electric vehicles are more suitable than hydrogen fuel cell vehicles in future energy system. Battery electric ve‐ hicles may, for a part of the transport demand, have limitations in their range. Hybrid tech‐ nologies may provide a good option, which can combine the high fuel efficiency of battery electric vehicles with efficient fuel cells in order to increase the range. Such hybrid vehicles have not been investigated in this dissertation.In the short term, electrolyser hydrogen is not suitable for fuel cell applications; and in the long term, some applications of electrolysers are more suitable than others. Other energy storage technologies, such as large heat pumps in CHP plants and battery electric vehicles, should be implemented first, because these technologies are more fuel and cost‐efficient. Electrolysers should only be implemented in energy systems with very high shares of in‐ termittent renewable energy and CHP; but in a 100 per cent renewable energy system, they constitute a key part, because they displace fuels derived from biomass. In such applica‐ tions, electrolysers should be developed to have the highest possible efficiency, the most flexible regulation abilities, and the lowest investment costs possible.

M3 - Ph.D. thesis

SN - 978-87-91830-26-6

BT - Fuel cells and electrolysers in future energy systems

PB - Institut for Samfundsudvikling og Planlægning, Aalborg Universitet

CY - Aalborg

ER -

Mathiesen BV. Fuel cells and electrolysers in future energy systems. Aalborg: Institut for Samfundsudvikling og Planlægning, Aalborg Universitet, 2008. 328 s. (ISP-Skriftserie; Nr. 2008-19).