`sector coupling` versus `model coupling`

[l-emele]

Description of the issue

The concepts sector coupling and model coupling are two concepts that are missing. Sometimes these two terms are used interchangeably by non-experts. But for the OEO we should clearly distinguish them. However, as there are some overlaps between the two concepts (e.g. sector coupling is often depicted by model coupling) we should discuss these terms together.

Ideas of solution

• Sector coupling is a process in which energy producers and energy consumers from multiple sectors interact.
• Model coupling is a model calculation in which output data from one or more models is used as input data for one or more other models,

Workflow checklist

• [ ] I discussed the issue with someone else than me before working on a solution
• [ ] I already read the latest version of the workflow for this repository
• [ ] The goal of this ontology is clear to me

I am aware that

• [ ] every entry in the ontology should have a definition
• [ ] classes should arise from concepts rather than from words

[l-emele]

• Sector coupling is a process in which energy producers and energy consumers from multiple sectors interact.
• Model coupling is a model calculation in which output data from one or more models is used as input data for one or more other models,

@OpenEnergyPlatform/oeo-domain-expert-energy-modelling : Any feedback on these proposals?

[u-mueller]

Both concepts are very important, I agree with your definition of model coupling, but the term sector coupling for me is often applied in the context of optimizing energy use the energy system, so this should be part of the definition. What about:

• Sector coupling is a process in which the interaction of energy producers and consumers from multiple sectors is modeled with the aim of optimizing the energy use of the energy system.

[l-emele]

I am fine with this.

[areleu]

From the BMWK: What is exactly sector coupling?

If we want to bring the energy transition to a long-term success, we cannot stop at transforming the power sector. We must also start using renewables for heating, cooling and transport. This can either be achieved by using renewables directly – for instance by using solar thermal energy to heat a house. Or by using electricity from renewables to bring the energy transition to other sectors. This transfer of clean electricity into other sectors, where it is used to reduce the amount of fossil energy required, is referred to as sector coupling.

The Clean Energy Wire states:

Sector coupling (German: Sektorkopplung) refers to the idea of interconnecting (integrating) the energy consuming sectors - buildings (heating and cooling), transport, and industry - with the power producing sector.

From Fridgen (2020):

Sector coupling (SC) describes the concept of a purposeful connection and interaction of energy sectors to increase the flexibility of supply, demand, and storing.

@u-mueller

Both concepts are very important, I agree with your definition of model coupling, but the term sector coupling for me is often applied in the context of optimizing energy use the energy system, so this should be part of the definition. What about:

* Sector coupling is a process in which the interaction of energy producers and consumers from multiple sectors is modeled with the aim of optimizing the energy use of the energy system.

I mostly agree but in that sense I would not define it as a direct subclass of process but of study which is already a subclass of process. I Think sector coupling is mostly used in context of analysing infrastructure developments

• Sector coupling is a study in which the interaction of energy producers and consumers from multiple sectors is analysed with the aim of optimizing the energy use of the(an?) energy system (the energy use of a system?).

[l-emele]

I disagree with defining sector coupling as study as study is a subclass of project which is defined as: A project is a process to achieve a specified goal that is unique in the sum of its conditions like its goal, time and cost budget and its organisation. That does not fit to sector coupling.

[areleu]

In general, sectors in the context of energy systems interact in one way or another. For example, in the old context of fossil fuels, the vehicle sector and power plant sector had definitively interactions mostly related to upstream production and supply chains. Is not like decoupled sectors really exists. What is different in this context is that the sectors and their interactions are explicitely being evaluated for a common goal, decarbonisation in this case.

[areleu]

Let me show further advantages of using study. We have analysis scope already axiomized. Which is also already axiomized with sector. So we can define a sector coupling study as a study whose analysis scope considers more than one sector.

[areleu]

If we try to be more strict on what we often see in the literature as sector coupling, we can define it in terms of infrastructure planning. Something like:

sector coupling is a project whose goal is of interest of agents (producers,consumers, prosumers) from multiple sectors.

[UStucky]

Hm, I am sorry, but I miss a defining item and I do not really agree with the definition:

1. The item: Has there been a definition of sector as part of the energy system? If not, we should have or give it together with the sector coupling definition. Sector means the type of use of energy which e.g. does not coincide with the physical energy types. It is mobility, power generation, heating, ...
2. a: There may be processes that enhance sector coupling (lead to more of it), but sector coupling itself is just the combination of types of usage (sectors) for - as correctly stated optimizing energy use. It is kind of a description of the energy system in terms of energy use. It is not a proces in itself. b: Studies are processes and there are studies in combination with sector coupling, of course. In areleu's comment https://github.com/OpenEnergyPlatform/ontology/issues/1521#issuecomment-1549227933 sector coupling studies are explitly termed and these are of course processes. But sector coupling is a property of the energy system, I would like to say. c: It is not a process, project or whatsoever of infrastructure planning, it is a goal of it. d: There is a lot of modeling in the planning and development process for a new energy system, and certainly in particular also for sector coupling. But sector coupling is the real fact, it is not a model or the process of modeling.
3. I also do not consider the past mutual influence via supply chains between traffic or mobility and power generation as a characteristics of sector coupling. Both use the products of the oil industry (mainly) and gas and also coal (in former times). But this is not sector coupling because there is no direct interaction between traffic and power generation in general. this, finally, brings me to a last characteristics of sector coupling. the coupling takes place in form of energy transfers between the sectors. So there is this connection of concurrency between mobility and power generation (no sector coupling) and there is also the connection that mobility brings the coal to the power station, but the train will not share energy with the station during the delivery action, hence, also no sector coupling.
4. See e.g. https://energiesysteme-zukunft.de/publikationen/stellungnahme-sektorkopplung/ (Dokument Stellungnahme) and https://www.dena.de/themen-projekte/energiesysteme/sektorkopplung/ as well as many other docs to be found by duckduckgoing on the web. I do not have a reference for my statement that energy transfer is a characteristics of sector coupling.

[stap-m]

1. The item: Has there been a definition of sector as part of the energy system? If not, we should have or give it together with the sector coupling definition. Sector means the type of use of energy which e.g. does not coincide with the physical energy types. It is mobility, power generation, heating, ...

@UStucky sector is part of the OEO. Please search for terms and definitions in protégé or here https://openenergy-platform.org/viewer/oeo/

[areleu]

2. c: It is not a process, project or whatsoever of infrastructure planning, it is a goal of it

With what you say in context I would argue that sector coupling is a process (maybe local, national, multinational project?) that has as as a goal a sector coupled energy system

3. I also do not consider the past mutual influence via supply chains between traffic or mobility and power generation as a characteristics of sector coupling. Both use the products of the oil industry (mainly) and gas and also coal (in former times). But this is not sector coupling because there is no direct interaction between traffic and power generation in general. this, finally, brings me to a last characteristics of sector coupling. the coupling takes place in form of energy transfers between the sectors. So there is this connection of concurrency between mobility and power generation (no sector coupling) and there is also the connection that mobility brings the coal to the power station, but the train will not share energy with the station during the delivery action, hence, also no sector coupling.

We would need then axioms to define the boundaries of a sector coupled energy system. There we can define the channels of interaction that characterize sector coupling, namely energy transfers. Otherwise, by allowing any kind of interaction cocurrency, supply and other kinds of interaction would classify as sector coupling.

This is particularly tricky given our existing definition of energy system:

An energy system is a supply system of spatially extended linked energy sources and sinks.

This means that everything that we allow within the boundaries of an energy system would be automatically sector coupled, if we characterize sector coupling soley on the fact that the sectors transfer energy among themselves. To avoid this, we could add a co-optimization clause but can that be axiomized or would be only identifiable by definition? We haven't really added any axioms that relate sector with energy system so far.

[areleu]

Just for completion, here is an exerpt from:

4. See e.g. https://energiesysteme-zukunft.de/publikationen/stellungnahme-sektorkopplung/ (Dokument Stellungnahme) and https://www.dena.de/themen-projekte/energiesysteme/sektorkopplung/ as well as many other docs to be found by duckduckgoing on the web. I do not have a reference for my statement that energy transfer is a characteristics of sector coupling.

Unter Sektorkopplung fällt beispielsweise der Ansatz, erneuerbare Energien in allen Bereichen der Energieversorgung direkt oder indirekt einzusetzen und das Energiesystemsektorübergreifend zu optimieren. Die noch starren Grenzen zwischen den Sektoren Strom, Wärme und Verkehr mit ihren unterschiedlichen Infrastruktursystemen, Märkten und Regulierungen müssen dabei aufgebrochen und Energieträger wie Strom, Erdgas, synthetische Brenn- und Kraftstoffe oder Biomasse flexibel und bedarfsgerecht in allen Anwendungsbereichen eingesetzt werden.

Automatic translation:

Sector coupling includes, for example, the approach of using renewable energies directly or indirectly in all areas of energy supply and optimising the energy system across all sectors. The still rigid boundaries between the electricity, heat and transport sectors with their different infrastructure systems, markets and regulations must be broken down and energy sources such as electricity, natural gas, synthetic fuels and biomass must be used flexibly and in line with demand in all areas of application.

[l-emele]

I found this definition from BDEW:

Der BDEW versteht unter Sektorkopplung die energietechnische und energiewirtschaftliche Verknüpfung von Strom, Wärme, Mobilität und industriellen Prozessen sowie deren Infrastrukturen mit dem Ziel einer Dekarbonisierung bei gleichzeitiger Flexibilisierung der Energienutzung in Industrie, Haushalt, Gewerbe/Handel/Dienstleistungen und Verkehr unter den Prämissen Wirtschaftlichkeit, Nachhaltigkeit und Versorgungssicherheit.

It is cited and translated in a paper:

Herein, the authors will use the definition of SC employed by the BDEW, which defines it as “the energy engineering and energy economy of the connection of electricity, heat, mobility and industrial processes, as well as their infrastructures, with the aim of decarbonization, while simultaneously increasing the flexibility of energy use in the sectors of industry and commercial/trade, households and transport under the premises of profitability, sustainability and security of supply”

I like this definition, because it shows that sector coupling is about various aspects:

• connecting sectors
• connecting infrastructures
• decarbonisation
• increasing flexibility of energy use

[carstenhoyerklick]

Within a the BMBF Kopernikus Projekt enavi we hat a lenghtly discussion on the definition of sector coupling. This has been condensed in paper: 10.1007/s12398-018-0241-3

[UStucky]

I still have the problem with the definition as a process. For me, a given process has to be defined by partial processes down to elementary activities. I do not see that there is a sector coupling process as such. There are processes of planning, they take sector coupling elements and include them into the plan of an eneregy system. There are processes of installing energy systems. They take devices that are designed to realize sector coupling and build them into the overall system. Like "communication system coupling" is a feature of modern cars, I consider sector coupling as a feature (or property) of energy systems. Can we say that there is a process of communication system coupling in vehicle construction or production. Well, there are processes or parts of processes to design, produce or install the communication devices, but is this really meant when saying: "My car is communication system coupled"? (I know we do rarely say it, I have just invented the term as an example) Otherwise we should define: "Sector coupling is the design/production/installing process of energy system equipment that connects sectors (by - some constraints, see below)" and maybe three different terms should be used for each level of realization. This is not how the term sector coupling is usally used, in my opinion. Lots of the definitions deal with optimisation, decarbonisation and similar arguments. Are they really defining items? These are the reasons for introducing or enhancing sector coupling, but do they really define it? On the other hand there are arguments like technically or economically connecting the sectors. These are defining items, but very general ones. We can take them as they are, then we have sector coupling almost since the beginning of technical energy usage (e.g. combing the forestry sector with the heating sector when some early inventor detected how to start a fire). That is ok for me, but if we consider this approach as being too general we should be more specific and constrained. Bringing energy tranfer into play was just a suggestion. It can be a criterion but probably not the only one.

[areleu]

From the source @carstenhoyerklick posted:

Sektorkopplung bezeichnet den fortschreitenden Prozess der Substitution fossiler Energieträger durch weit überwiegend erneuerbar erzeugten Strom oder durch andere erneuerbare Energieträger und nachhaltige Energienutzungsformen, wie die Nutzung von Abwärme, in neuen sektorenübergreifenden Anwendungen oder durch verstärkte Nutzung bekannter sektorenübergreifender Anwendungen.

This analysis comes back to defining as a process. One counter argument for not using project is, I would argue, that a project is a process with a goal, this means that there is some end to sector coupling, the aformentioned sector coupled energy system. If the latter is something that does not exist in the sense that there is no objective way of telling what would such a thing be then we cannot assign it as a goal.

@UStucky:

I still have the problem with the definition as a process. For me, a given process has to be defined by partial processes down to elementary activities. I do not see that there is a sector coupling process as such. There are processes of planning, they take sector coupling elements and include them into the plan of an eneregy system. There are processes of installing energy systems. They take devices that are designed to realize sector coupling and build them into the overall system. Like "communication system coupling" is a feature of modern cars, I consider sector coupling as a feature (or property) of energy systems. Can we say that there is a process of communication system coupling in vehicle construction or production. Well, there are processes or parts of processes to design, produce or install the communication devices, but is this really meant when saying: "My car is communication system coupled"? (I know we do rarely say it, I have just invented the term as an example) ...

BFO implementation of process:

p is a process = Def. p is an occurrent that has temporal proper parts and for some time t, p s-depends_on some material entity at t. (axiom label in BFO2 Reference: [083-003])

Is not stated explicitely but processes can be part of other processes. Although I do not really know what happens with cocurrency, we would need some feedback from @OpenEnergyPlatform/oeo-general-expert-formal-ontology

This just me throwing ideas around but what about sector coupling being a policy/policy instrument? The way @UStucky is defining it seems to me like a dependent continuant depending on some energy system, a quality is inherent to the system, which is not the case for SC. A realizable entity would only make sense if we define an asociated process. So a policy seems to be fitting to me, given the coarse scope of the definition.

policy: A policy is a specifically dependent continuant that is a deliberate system of principles, rules and guidelines, adopted by an organisation to guide decision making with respect to particular situations and implemented to achieve stated goals.

policy instrument: A policy instrument is a specifically dependent continuant that is an action by the government that is intended to promote the adoption of a (transformative) measure.

[areleu]

Other thread of thought I have is sector coupling as an instance of tactic but for that we are missing a bunch of axioms for strategy, tactic, goal, problem and who knows what else.

Is sector coupling a tactic to realize the energy transition which in place is a strategy to solve the problems of fossil fuel dependency and climate change?

[stap-m]

policy instrument: A policy instrument is a specifically dependent continuant that is an action by the government that is intended to promote the adoption of a (transformative) measure.

Be aware of #1507 😬

[UStucky]

I may still not fully understand the BFO, but yes, sector coupling as I have characterized it should be a dependent continuant. It depends on sector and on energy system. I like to take a close view on the classes and also on object-oriented design of applications that use the ontology. One important point is, that sector coupling as an instance in an application could refer to an energy system and to the sector coupling subsystems as well as to the sectors that are coupled in each case. The energy system can also refer back to the sector coupling object, thereby giving access to it in one step. The next important point is that in designing a computer application the main focus lies on methods which to my opinion should include explictly the data model when we think of getters and setters. Getters give access to data directly, but if all that is seen from external, it is not important if the data is explicitely stored and referenced as an attribute/property/association etc. or if it is calculated at runtime when the question is asked (the getter is invoked); in my opinion the latter means the same as reasoning/inferring in ontology speaking. Other methods, inasmuch as they return results, are also comparable to these ontological functions. So, you e.g. can ask an energy system: "Are you sector coupled?" and you get the answer yes or no or maybe a reference to the sector coupling object if it exists. This object can be further questioned for sectors that are coupled, equipment that builds the coupling subsystem, etc. So, this is my favorite candidate of a "sector coupling". It really helps to imagine, e.g. with the view of an object-oriented developer, how to apply the ontology. On the other hand, I think I can also understand the other suggestions that have been made. And I believe it is due to a homonymization of the term. There is sector coupling (take my view for the moment, please), and ther are processes to plan, produce, and install sector coupling measures, and there are policies that deal with sector coupling – which are the originators of the goals of decarbonization and optimization etc. These other sector coupling entities might be called "sector coupling planning" "sector coupling install process" and "Sector coupling policy (instrument)". But all those meanings depend on a clear definition of the "sector coupling" that i have tried to sketch. Like I wrote yesterday for sector coupling processes, my term "sector coupling" should be defined as the existence of connections between sectors in the energy system – with some contraints that we seem not to know or oversee at the moment. Without constrints, almost every energy system has sector coupling (even those in ancient times) and of course we should explixtly identify all "coupling points". But indeed, as the term is actually used, there are constraints, e.g. an energy transfer between sectors as I suggested. We do not have the complete list, it is our task to compile it – and I hope that it already exists somewhere :-D

[areleu]

policy instrument: A policy instrument is a specifically dependent continuant that is an action by the government that is intended to promote the adoption of a (transformative) measure.

Be aware of #1507 😬

IMHO this is very related. I think we are missing a lot of Policy theory vocabulary. There is probably more sophisticated terms than the previously mentioned strategy and tactic .

I like to take a close view on the classes and also on object-oriented design of applications that use the ontology.

The closest application I can currently think about is the OEKG. But I think that the ontology definition should precede the software implementation and not the other way around. This is because by design, the OEO is primarily a reference ontology (for annotation) , not an application ontology, or so I understood from the paper. Applications then should refer to the ontology only for annotation porpouses. For instance I think object-oriented design is beyond scope.

If we want to expand the ontology to other kinds of applications we have always the option of generating subsets of the ontology in the form of OWL profiles. OWL profiles are used to create ontologies specific to some applications. For example the EL profile works for ontologies with a lot of classes, whereas the RL profile is designed with applications with reasoning in mind. I recently closed an issue regarding alternative profiles #1430 but if we see the need of opening it another issue for some specific profile we can always do that.

Like I wrote yesterday for sector coupling processes, my term "sector coupling" should be defined as the existence of connections between sectors in the energy system – with some contraints that we seem not to know or oversee at the moment.

This definition sounds definitively like specifically dependant continuant to me, specifically a quality or a pattern that is built into a independent continuant, an energy system in this case. Barry Smith explains something very similar in this Ontology of social services video Minute 10:50 to around 12:00. Previously I discarded quality because what sector coupling is needed to exist, but if we define what are the patterns that define sector coupling then the energy system can bear sector coupling very well.

sector coupling: sector coupling is a quality of connectiveness of an an energy system that ...

[u-mueller]

As discussed in the OEO-Dev meeting today, for a start we can implement sector coupling as a plan specification and use the definition of the BDWE l-emele cited above: Sector coupling is a plan specification that intends to connect electricity, heat, mobility and industrial processes, as well as their infrastructures, with the aim of decarbonization, while simultaneously increasing the flexibility of energy use in the sectors of industry and commercial/trade, households and transport under the premises of profitability, sustainability and security of supply.

or more condensed:

Sector coupling is a plan specification that intends to connect electricity, heat, mobility and industrial processes, as well as their infrastructures, with the aim of decarbonization, while simultaneously optimizing the use of energy in the sectors of industry and commercial/trade, households and transport.

I think as a descriptor term for the scenario factsheets this will do, even though we may need another concept for describing how the coupling of energy sectors is realized physically in the end.

[l-emele]

Sector coupling is a plan specification that intends to connect electricity, heat, mobility and industrial processes, as well as their infrastructures, with the aim of decarbonization, while simultaneously optimizing the use of energy in the sectors of industry and commercial/trade, households and transport.

I agree to this proposal.

[areleu]

What about something more generic like:

Sector coupling is a plan specification that intends to connect energy transformation processes and their related infrastructure, with the aim of decarbonization, while simultaneously optimizing energy consuming processes.

Otherwise it has so many specifications that it might as well be an instance and not a subclass.

[UStucky]

I like the shortest, maybe I would also skip decarbonization because there could also be sector coupling measures that do not prevent carbon based fuels; optimization is the general goal (which in an extended explanation could mean minimization of costs, environmental impact for all kinds of energy generation, and making the energy system more sustainable)

[l-emele]

I think sectors should be part of the definition. After all, it is about defining sector coupling.

[areleu]

Sector coupling is a plan specification that intends to connect and optimize energy consumpiton of energy transformation processes from more than one sector, along their related infrastructure. Its realization may have goals common to all its associated sectors such as decarbonization.

The last part is pretty hard...

[UStucky]

Maybe we could substitute "establish and optimize energy flows across sectorial borders with respect to cost, environmental impact, and sustainability" for "optimize energy consumption of energy transformation processes from more than one sector"

[u-mueller]

I suggest to find a final definition in the next Dev-Meeting, I don't see that we can solve the issue here. I put it on the agenda.

[stap-m]

I am ok with discussing this in a meeting evetually. Anyway, I think the written discussion may be helpful for preparation, because one has time to read and think...

In general, I prefer short definition, too. We can extend it with longer elucidations. E.g. like this:

• Definition: Sector coupling is a plan specification that intends to connect processes from the electricity, heat, mobility or industrial sectors, as well as their infrastructures.
• Elucidation: By establishing energy flows across sectorial borders the aim of sector coupling is usually an optimization e.g. with respect to cost, environmental impact, sustainability and decarbonisation of the energy system.

[l-emele]

In OEO dev meeting 60 we had only little time to discuss this topic. But we had at least a few conclusions:

• distinguish between sector coupling and coupled sectors (with "coupled" as quality)
• seems we need both the process of sector coupling and coupling as plan specification

[l-emele]

I revisited the discussions and here are some proposals based upon:

• New quality coupled: coupled is quality of a sector that describes that processes in the specific sector are interconnected with processes in other sectors.
• Sector coupling as plan specification / technology: A sector coupling technology is ~plan specification~ technology that intends to connect processes from the electricity, heat, mobility or industrial sectors, as well as their infrastructures. This is a refinement of the last proposal were sector coupling was proposed to be defined as plan specification. The class technology is defined as: A technology is a plan specification that describes how to combine artificial objects or other material entities and processes in a specific way.
• Sector coupling as process: sector coupling is a process of connecting processes from the electricity, heat, mobility or industrial sectors as well as their infrastructures

[stap-m]

• New quality coupled: coupled is quality of a sector that describes that processes in the specific sector are interconnected with processes in other sectors.

What would be the use case of coupled? In the proposals above are no axioms or examples given that would use it.

[stap-m]

I am ok with the proposals for sector coupling technology and sector coupling process.

In general, I prefer short definition, too. We can extend it with longer elucidations. E.g. like this:

• Elucidation: By establishing energy flows across sectorial borders the aim of sector coupling is usually an optimization e.g. with respect to cost, environmental impact, sustainability and decarbonisation of the energy system.

What about adding this elucidation to either the process, or to both, as already proposed above? I'd somehow relate both classes to each other, via axioms at least.

[stap-m]

The proposal for model coupling in the header is also fine for me.

[areleu]

I am ok with the proposals for sector coupling technology and sector coupling process.

In general, I prefer short definition, too. We can extend it with longer elucidations. E.g. like this:

• Elucidation: By establishing energy flows across sectorial borders the aim of sector coupling is usually an optimization e.g. with respect to cost, environmental impact, sustainability and decarbonisation of the energy system.

What about adding this elucidation to either the process, or to both, as already proposed above? I'd somehow relate both classes to each other, via axioms at least.

Would it make more sense to use an energy system instead of the energy system? Since I think that a system is subject to boundary definition, I consider ambiguous to talk about a system that contains it all.

[stap-m]

Looks like an agreement on sector coupling, sector coupling technology and model coupling. I'll implement.