KH
K. Hemmes
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Fuel cells are electrochemical devices that are conventionally used to convert the chemical energy of fuels into electricity while producing heat as a byproduct. High temperature fuel cells such as molten carbonate fuel cells and solid oxide fuel cells produce significant amounts of heat that can be used for internal reforming of fuels such as natural gas to produce gas mixtures which are rich in hydrogen, while also producing electricity. This opens up the possibility of using high temperature fuel cells in systems designed for flexible coproduction of hydrogen and power at very high system efficiency. In a previous study, the flowsheet software Cycle-Tempo has been used to determine the technical feasibility of a solid oxide fuel cell system for flexible coproduction of hydrogen and power by running the system at different fuel utilization factors (between 60 and 95%). Lower utilization factors correspond to higher hydrogen production while at a higher fuel utilization, standard fuel cell operation is achieved. This study uses the same basis to investigate how a system with molten carbonate fuel cells performs in identical conditions also using Cycle-Tempo. A comparison is made with the results from the solid oxide fuel cell study.
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Fuel cells are electrochemical devices that are conventionally used to convert the chemical energy of fuels into electricity while producing heat as a byproduct. High temperature fuel cells such as molten carbonate fuel cells and solid oxide fuel cells produce significant amounts of heat that can be used for internal reforming of fuels such as natural gas to produce gas mixtures which are rich in hydrogen, while also producing electricity. This opens up the possibility of using high temperature fuel cells in systems designed for flexible coproduction of hydrogen and power at very high system efficiency. In a previous study, the flowsheet software Cycle-Tempo has been used to determine the technical feasibility of a solid oxide fuel cell system for flexible coproduction of hydrogen and power by running the system at different fuel utilization factors (between 60 and 95%). Lower utilization factors correspond to higher hydrogen production while at a higher fuel utilization, standard fuel cell operation is achieved. This study uses the same basis to investigate how a system with molten carbonate fuel cells performs in identical conditions also using Cycle-Tempo. A comparison is made with the results from the solid oxide fuel cell study.
A personal retrospect on three decades of high temperature fuel cell research
Ideas and lessons learned
In 1986 the Dutch national fuel cell program started. Fuel cells were developed under the paradigm of replacing conventional technology. Coal-fired power plants were to be replaced by large-scale MCFC power plants fuelled by hydrogen in a full-scale future hydrogen economy. With today's knowledge we will reflect on these and other ideas with respect to high temperature fuel cell development including the choice for the type of high temperature fuel cell. It is explained that based on thermodynamics proton conducting fuel cells would have been a better choice and the direct carbon fuel cell even more so, with electrochemical gasification of carbon as the ultimate step. The specific characteristics of fuel cells and multisource multiproduct systems were not considered, whereas we understand now that these can provide huge driving forces for the implementation of fuel cells compared to just replacing conventional combined heat and power production technology.
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In 1986 the Dutch national fuel cell program started. Fuel cells were developed under the paradigm of replacing conventional technology. Coal-fired power plants were to be replaced by large-scale MCFC power plants fuelled by hydrogen in a full-scale future hydrogen economy. With today's knowledge we will reflect on these and other ideas with respect to high temperature fuel cell development including the choice for the type of high temperature fuel cell. It is explained that based on thermodynamics proton conducting fuel cells would have been a better choice and the direct carbon fuel cell even more so, with electrochemical gasification of carbon as the ultimate step. The specific characteristics of fuel cells and multisource multiproduct systems were not considered, whereas we understand now that these can provide huge driving forces for the implementation of fuel cells compared to just replacing conventional combined heat and power production technology.
Solid oxide fuel cell systems for combined heat and power production (SOFC μCHP) fueled by natural gas are attractive because of their high electrical and total efficiency even at small scale. The development of a hydrogen economy will increase the availability of distributed hydrogen as a pure gas. Alternatively, hydrogen may be blended with natural gas in the grid. This study investigates the performance of SOFC μCHP systems, while using a fuel varying from pure hydrogen to pure methane via mixtures of hydrogen and methane called Hythane. Flowsheet models of external as well as internal reforming fuel cell systems were developed in Cycle-Tempo simulation software. Results show that both the external as well as the internal reforming system can operated on all fuel gas compositions varying from pure hydrogen to pure methane, thus allowing for a transition towards a hydrogen economy via the mixing of hydrogen into the natural gas grid. Although the natural gas based systems have a higher electrical efficiency, the introduction of hydrogen into the gas leads to a higher total efficiency of the combined heat and power system. The addition of hydrogen into the fuel minimizes the problems of thermal stress and thermal shock associated with the use of methane in internal reforming fuel cell systems. The internal reforming system showed a higher performance compared to the external reforming system for all Hythane gas mixtures in terms of not only electrical efficiency but also in terms of thermal and total efficiency.
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Solid oxide fuel cell systems for combined heat and power production (SOFC μCHP) fueled by natural gas are attractive because of their high electrical and total efficiency even at small scale. The development of a hydrogen economy will increase the availability of distributed hydrogen as a pure gas. Alternatively, hydrogen may be blended with natural gas in the grid. This study investigates the performance of SOFC μCHP systems, while using a fuel varying from pure hydrogen to pure methane via mixtures of hydrogen and methane called Hythane. Flowsheet models of external as well as internal reforming fuel cell systems were developed in Cycle-Tempo simulation software. Results show that both the external as well as the internal reforming system can operated on all fuel gas compositions varying from pure hydrogen to pure methane, thus allowing for a transition towards a hydrogen economy via the mixing of hydrogen into the natural gas grid. Although the natural gas based systems have a higher electrical efficiency, the introduction of hydrogen into the gas leads to a higher total efficiency of the combined heat and power system. The addition of hydrogen into the fuel minimizes the problems of thermal stress and thermal shock associated with the use of methane in internal reforming fuel cell systems. The internal reforming system showed a higher performance compared to the external reforming system for all Hythane gas mixtures in terms of not only electrical efficiency but also in terms of thermal and total efficiency.
Life Cycle Assessment in Early Stages of Technology Development
The Case for Rural Electrification
Most applications of LCA deal with environmental compliance, strategic development and environmental product declarations. While useful, these evaluations are reserved for technologies and products that have already reached a level of maturity and commercialization that does not allow much improvement on their environmental performance. Being retrospective and reactive, these assessments miss out on the opportunity of making any recommendation or improvement before the environmental impact of a technology is locked-in.For the purposes of guiding technology development from early design stages, the existing LCA framework needs to be adapted in order to cope with the hurdles proper of the evaluation of technologies that are still under development. Recent efforts include techniques to deal with scarce and uncertain data, scaling pilot/lab scale to full-fledged performances as well as background and landscape future changes.This study draws on knowledge available on scaling relations, uncertainty analysis and multi criteria decision analysis as resources for the application of LCA in the development of emerging technologies for distributed rural electrification. As a case study, three different direct carbon fuel cell (DCFC) designs were compared to a photovoltaic microgrid and evaluated for their environmental performance. So far only developed in laboratory scale, inventory data for DCFC was scaled up based on the desired power capacity and estimated future performance for the electrification of a hypothetical health clinic in rural Uganda. Results reveal that within the boundaries of this study and considering the ideal performance expected for future deployment, DCFC with a solid oxide conducting electrolyte can be a competitive alternative to a PV microgrid, when considering life cycle environmental performance. Conducting an early LCA helped identify DCFC designs with the most environmental promise and revealed environmental hotspots of DCFC for attention towards further development.
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Most applications of LCA deal with environmental compliance, strategic development and environmental product declarations. While useful, these evaluations are reserved for technologies and products that have already reached a level of maturity and commercialization that does not allow much improvement on their environmental performance. Being retrospective and reactive, these assessments miss out on the opportunity of making any recommendation or improvement before the environmental impact of a technology is locked-in.For the purposes of guiding technology development from early design stages, the existing LCA framework needs to be adapted in order to cope with the hurdles proper of the evaluation of technologies that are still under development. Recent efforts include techniques to deal with scarce and uncertain data, scaling pilot/lab scale to full-fledged performances as well as background and landscape future changes.This study draws on knowledge available on scaling relations, uncertainty analysis and multi criteria decision analysis as resources for the application of LCA in the development of emerging technologies for distributed rural electrification. As a case study, three different direct carbon fuel cell (DCFC) designs were compared to a photovoltaic microgrid and evaluated for their environmental performance. So far only developed in laboratory scale, inventory data for DCFC was scaled up based on the desired power capacity and estimated future performance for the electrification of a hypothetical health clinic in rural Uganda. Results reveal that within the boundaries of this study and considering the ideal performance expected for future deployment, DCFC with a solid oxide conducting electrolyte can be a competitive alternative to a PV microgrid, when considering life cycle environmental performance. Conducting an early LCA helped identify DCFC designs with the most environmental promise and revealed environmental hotspots of DCFC for attention towards further development.
Fuel cells are well-known electrochemical devices for the production of electricity and heat. However also other functionalities are induced into the fuel cell by the membrane electrolyte that can be used advantageously. In contrast to combustion in which only one exhaust gas exits the combustion chamber a fuel cell is a device with two inlets and two separate outlet gas streams. This allows for the use of a fuel cell as a separator device. An example is the separation of CO2 gas from the off gas of a coal-fired power plant, using a molten carbonate fuel-cell. It also allows for the development of fuel cell reactors being a generalized concept of the fuel cell in which chemicals can be produced via electrochemical reactions using electric control for optimizing the process. In this paper an overview is given of these innovative possibilities and functionalities.
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Fuel cells are well-known electrochemical devices for the production of electricity and heat. However also other functionalities are induced into the fuel cell by the membrane electrolyte that can be used advantageously. In contrast to combustion in which only one exhaust gas exits the combustion chamber a fuel cell is a device with two inlets and two separate outlet gas streams. This allows for the use of a fuel cell as a separator device. An example is the separation of CO2 gas from the off gas of a coal-fired power plant, using a molten carbonate fuel-cell. It also allows for the development of fuel cell reactors being a generalized concept of the fuel cell in which chemicals can be produced via electrochemical reactions using electric control for optimizing the process. In this paper an overview is given of these innovative possibilities and functionalities.
In this paper we describe and analyze the results of experiments on a Solid Oxide ElectrolyzerCell with and without the supply of a fuel to the oxygen producing electrode. In theexperiments a 5 x 5 cm2 Solid Oxide Fuel Cell is used operating in electrolyzer mode. Wehave tested the influence of varying reactant utilization (i.e. steam utilization) and fuelutilization in fuel assisted electrolysis. In particular the effect of insufficient fuel supplywas studied experimentally as well as theoretically. In doing so we defined a turning pointat which all the fuel is utilized. It was shown that by supplying not enough fuel all the fuelis oxidized and as in conventional electrolysis, oxygen production will start and oxygen isleaving the cell. Moreover the cell performance approaches conventional electrolysis andthe effect of adding fuel on reducing the necessary amount of electric power almost vanishes.As in conventional high temperature steam electrolysis conversion efficiencies ofmore than hundred percent can be achieved also with fuel assisted electrolysis, under thecondition that sufficient fuel is supplied i.e. fuel utilization must be lower than hundredpercent.We have put the concept of fuel assisted electrolysis in the framework of multisourcemultiproduct energy systems (MSMP's) and emphasized for example the benefits of usingbio(syn)gas as the fuel in fuel assisted electrolysis. When using bio(syn)gas, the gas is defacto upgraded to pure hydrogen. This is an additional benefit next to the lowering of theelectric power consumption for producing the same amount of hydrogen in the fuelassisted electrolysis process. Furthermore the suitability of these flexible MSMP systems ina market with volatile electricity prices due to increasing penetration of intermittentrenewable energy sources is highlighted.
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In this paper we describe and analyze the results of experiments on a Solid Oxide ElectrolyzerCell with and without the supply of a fuel to the oxygen producing electrode. In theexperiments a 5 x 5 cm2 Solid Oxide Fuel Cell is used operating in electrolyzer mode. Wehave tested the influence of varying reactant utilization (i.e. steam utilization) and fuelutilization in fuel assisted electrolysis. In particular the effect of insufficient fuel supplywas studied experimentally as well as theoretically. In doing so we defined a turning pointat which all the fuel is utilized. It was shown that by supplying not enough fuel all the fuelis oxidized and as in conventional electrolysis, oxygen production will start and oxygen isleaving the cell. Moreover the cell performance approaches conventional electrolysis andthe effect of adding fuel on reducing the necessary amount of electric power almost vanishes.As in conventional high temperature steam electrolysis conversion efficiencies ofmore than hundred percent can be achieved also with fuel assisted electrolysis, under thecondition that sufficient fuel is supplied i.e. fuel utilization must be lower than hundredpercent.We have put the concept of fuel assisted electrolysis in the framework of multisourcemultiproduct energy systems (MSMP's) and emphasized for example the benefits of usingbio(syn)gas as the fuel in fuel assisted electrolysis. When using bio(syn)gas, the gas is defacto upgraded to pure hydrogen. This is an additional benefit next to the lowering of theelectric power consumption for producing the same amount of hydrogen in the fuelassisted electrolysis process. Furthermore the suitability of these flexible MSMP systems ina market with volatile electricity prices due to increasing penetration of intermittentrenewable energy sources is highlighted.
Journal article
(2016)
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A Ligtvoet, EHWJ Cuppen, O Di Ruggero, K Hemmes, U Pesch, JN Quist, DC Mehos
This paper reports on the refinement of constructive conflict methodology (CCM) combining Q methodology and stakeholder dialogue workshops for gas futures for the Netherlands. Since the end of the 1950s, natural gas exploration and exploitation has been a major focus of the Dutch energy policy. Discussions about the future of energy in the Netherlands tend to focus either on pro-gas or pro-renewable energy. Using Q methodology we have constructed more nuanced perspectives on the future of energy in the Netherlands. We used these perspectives in a stakeholder dialogue, in
which the participants further detailed the perspectives and discussed future policy options. Analysis of the outcomes of this process teaches us that the Netherlands remain gas-focused, that renewable energy sources are as much a dogma as nuclear power was in the 1960s, and that the prospect of an austere future is a non-debatable issue. From a methodological perspective it can be concluded that the refined methodology contributed to diversity in views, opened up the dominant discourse and led to learning among participating stakeholders. ...
which the participants further detailed the perspectives and discussed future policy options. Analysis of the outcomes of this process teaches us that the Netherlands remain gas-focused, that renewable energy sources are as much a dogma as nuclear power was in the 1960s, and that the prospect of an austere future is a non-debatable issue. From a methodological perspective it can be concluded that the refined methodology contributed to diversity in views, opened up the dominant discourse and led to learning among participating stakeholders. ...
This paper reports on the refinement of constructive conflict methodology (CCM) combining Q methodology and stakeholder dialogue workshops for gas futures for the Netherlands. Since the end of the 1950s, natural gas exploration and exploitation has been a major focus of the Dutch energy policy. Discussions about the future of energy in the Netherlands tend to focus either on pro-gas or pro-renewable energy. Using Q methodology we have constructed more nuanced perspectives on the future of energy in the Netherlands. We used these perspectives in a stakeholder dialogue, in
which the participants further detailed the perspectives and discussed future policy options. Analysis of the outcomes of this process teaches us that the Netherlands remain gas-focused, that renewable energy sources are as much a dogma as nuclear power was in the 1960s, and that the prospect of an austere future is a non-debatable issue. From a methodological perspective it can be concluded that the refined methodology contributed to diversity in views, opened up the dominant discourse and led to learning among participating stakeholders.
which the participants further detailed the perspectives and discussed future policy options. Analysis of the outcomes of this process teaches us that the Netherlands remain gas-focused, that renewable energy sources are as much a dogma as nuclear power was in the 1960s, and that the prospect of an austere future is a non-debatable issue. From a methodological perspective it can be concluded that the refined methodology contributed to diversity in views, opened up the dominant discourse and led to learning among participating stakeholders.
The development of offshore wind energy systems is a complex challenge from a technical, socio-economic, ethical and legal perspective. The proposed paper elaborates a general framework for systematically embedding social responsibility into the technical and institutional design of offshore wind energy systems. Taking a systems perspective we investigate how values can be embedded in the technical design of offshore energy systems in relation to other surrounding (energy) systems and beyond. Thereby we use a value sensitive design approach. Here, the empirical basis is given by the current development of offshore wind in the Netherlands and the values and conflicts articulated by various stakeholder groups. The conceptual framework is provided by the capability approach. It will be argued that the capability approach is particularly well suited for addressing ethical issues in the context of energy supply (and demand) as it allows taking into account positive and negative aspects of various energy technologies, while also including their positive aspects in the terms of freedom of action. In this respect, a capability perspective distinguishes itself from various other forms of ethical assessments that predominantly focus on the negative impacts of technology. We will sketch how the institutional design of offshore wind energy systems addresses the regulation and governance of the energy sector in relation to the ethical requirements that arise in a value sensitive design approach as sketched above.
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The development of offshore wind energy systems is a complex challenge from a technical, socio-economic, ethical and legal perspective. The proposed paper elaborates a general framework for systematically embedding social responsibility into the technical and institutional design of offshore wind energy systems. Taking a systems perspective we investigate how values can be embedded in the technical design of offshore energy systems in relation to other surrounding (energy) systems and beyond. Thereby we use a value sensitive design approach. Here, the empirical basis is given by the current development of offshore wind in the Netherlands and the values and conflicts articulated by various stakeholder groups. The conceptual framework is provided by the capability approach. It will be argued that the capability approach is particularly well suited for addressing ethical issues in the context of energy supply (and demand) as it allows taking into account positive and negative aspects of various energy technologies, while also including their positive aspects in the terms of freedom of action. In this respect, a capability perspective distinguishes itself from various other forms of ethical assessments that predominantly focus on the negative impacts of technology. We will sketch how the institutional design of offshore wind energy systems addresses the regulation and governance of the energy sector in relation to the ethical requirements that arise in a value sensitive design approach as sketched above.
The penetration of renewable energies such as wind and solar into the energy Market on a large scale introduces periods of electricity surpluses and shortages of supply caused by the intermittent nature of these sources, leading too uncertainty and sometimes instability in the operation of the grid. This paper proposes HyperWind; a Solid Oxide cell used for flexible power and high quality hydrogen co-production. It is an alternative solution to mitigate power surplus or periods of low power production with high demand in the operation of the renewable energy sources, using the multisource-multiproduct feature of the Solid Oxide Cells that can both produce electricity or consume electricity combined with high quality Hydrogen production in a flexible way with the option of upgrading hydrogen mixtures (biogas) into pure hydrogen.
Hyperwind; facilitating the penetration of renewable energies and hydrogen... | Request PDF. Available from: https://www.researchgate.net/publication/290100501_Hyperwind_facilitating_the_penetration_of_renewable_energies_and_hydrogen_mobility_by_MSMP%27s [accessed Jan 16 2018]. ...
Hyperwind; facilitating the penetration of renewable energies and hydrogen... | Request PDF. Available from: https://www.researchgate.net/publication/290100501_Hyperwind_facilitating_the_penetration_of_renewable_energies_and_hydrogen_mobility_by_MSMP%27s [accessed Jan 16 2018]. ...
The penetration of renewable energies such as wind and solar into the energy Market on a large scale introduces periods of electricity surpluses and shortages of supply caused by the intermittent nature of these sources, leading too uncertainty and sometimes instability in the operation of the grid. This paper proposes HyperWind; a Solid Oxide cell used for flexible power and high quality hydrogen co-production. It is an alternative solution to mitigate power surplus or periods of low power production with high demand in the operation of the renewable energy sources, using the multisource-multiproduct feature of the Solid Oxide Cells that can both produce electricity or consume electricity combined with high quality Hydrogen production in a flexible way with the option of upgrading hydrogen mixtures (biogas) into pure hydrogen.
Hyperwind; facilitating the penetration of renewable energies and hydrogen... | Request PDF. Available from: https://www.researchgate.net/publication/290100501_Hyperwind_facilitating_the_penetration_of_renewable_energies_and_hydrogen_mobility_by_MSMP%27s [accessed Jan 16 2018].
Hyperwind; facilitating the penetration of renewable energies and hydrogen... | Request PDF. Available from: https://www.researchgate.net/publication/290100501_Hyperwind_facilitating_the_penetration_of_renewable_energies_and_hydrogen_mobility_by_MSMP%27s [accessed Jan 16 2018].