Redefine `technology` and include subclasses

[l-emele]

Description of the issue

Discussion in https://github.com/OpenEnergyPlatform/oekg/issues/43 has shown that our current definition of technology[^1] is not useful for the OEKG use case. Also for the OEKG use case we need subclasses.

[^1]: A Technology is an information content entity that specifies how to create an artificial object.

Ideas of solution

If you already have ideas for the solution describe them here

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]

My proposal for a redefinition of technology is: A technology is a plan specification that describes how to combine artificial objects or other material entities and processes in a specific way.

From that I propose define energy technology: An energy technology is a technology that describes how to combine energy transformation units, energy transformations, energy carriers and energy in a specific way. Alternatively, we could label this as energy transformation technology. This class could then be the anchor what is needed in https://github.com/OpenEnergyPlatform/oekg/issues/43.

To spell out some subclasses that are needed for the OEKG:

• energy technology as proposed
  • power generation technology: A power generation technology is an energy technology that describes how to combine energy transformation units and energy carriers to generate electricity.
  • wind power technology: A wind power technology is a power generation technology that describes how to generate electricity using wind energy converting units (wind turbines).
    • offshore wind power technology: An offshore wind power technology is a wind power technology that describes how to generate electricity using wind energy converting units (wind turbines) in offshore wind farms.
  • power-to-fuel technology: A power to fuel technology is an energy technology that describes how to combine power-to-fuel system, electrical energy and portions of matter in power-to-fuel processes.
• mobility technology: A mobility technology is a technology that describes how vehicles participate in transport.
  • electric mobility technology: An electric mobility is a technology that describes how electric vehicles participate in transport.

We instead define the following relations via new object properties:

• technology 'describes process' some process': A relation between a technology and a process in which the technology describes how to combine the process with artificial objects or other material entities in a specific way.
• technology 'describes artificial object' some 'artificial object': A relation between a technology and an artificial in which the technology describes how to combine the artificial object with other material entities and processes in a specific way.
• technology 'describes participant' some 'material entity': A relation between a technology and an artificial in which the technology describes how to combine the material entity with other material entities and processes in a specific way.

And more specific for energy technology:

• energy technology 'describes process' some 'energy transformation': A relation between an energy technology and an energy transformation in which the technology describes how to combine the energy transformation with energy transformation units and other material entities in a specific way.
• energy technology 'describes artificial object' some 'energy transformation unit'': A relation between an energy technology and an energy transformation unit in which the energy technology describes how to combine the energy transformation unit with material entities and energy transformations in a specific way.
• energy technology 'describes energy input' some energy: A relation between an energy technology and an energy in which the energy technology describes how the energy is input to the energy transformation described by the technology.
• energy technology 'describes energy output' some energy: A relation between an energy technology and an energy in which the energy technology describes how the energy is output to the energy transformation described by the technology.
• energy technology 'describes material input' some 'portion of matter': A relation between an energy technology and an energy in which the energy technology describes how the material entity is input to the energy transformation described by the technology.
• energy technology 'describes material output' some 'portion of matter': A relation between an energy technology and an energy in which the energy technology describes how the material entity is output of the energy transformation described by the technology.

Sorry for this long comment but https://github.com/OpenEnergyPlatform/oekg/issues/43 sparked a lot of ideas which I wanted to keep.

[l-emele]

An alternative approach to the specific object properties would be to have only one axiom that catches all.

For example for the wind offshore technology something like: 'is about' some 'wind energy converting unit' and ('part of' some 'offshore wind farm') and ('participates in' some 'wind energy transformation')

Or for electric mobility technology: 'is about' some 'electric vehicle' and 'participates in' some transport

This might also help solving the problem described in https://github.com/OpenEnergyPlatform/ontology/issues/1350#issuecomment-1573604989 as we then probably a lot of participates in axioms only within 'technology X' 'is about' Y 'participates in' some Z axioms, but not directly at Y.

[stap-m]

Thanks @l-emele I like the proposals! Since it is so long, I needed some time to answer. I like the one-axiom-only approach. I added some brackets to the axiom: 'technology' 'is about' some ('artifictial object' and 'participates in' some process)

[l-emele]

Discussed bilaterally with @stap-m :

• Agreement on new technology definition as proposed: A technology is a plan specification that describes how to combine artificial objects or other material entities and processes in a specific way.
• We prefer the second option with the large combined axioms. We'll try this in two separate branches for power generation technologies (@l-emele) and heat generation technologies (@stap-m).
• Storage and PtX technologies after that.
• Mobility needs additional thoughts because of different types of artifical objects (vehicles versus ways).
• Show implemented ideas in next OEO dev meeting.

[stap-m]

I had the idea of adding an elucidation to technology to say that the structure was built explicitly to depict the technologies used in energy modelling.

About heat technologies: The axioms for geothermal and solar are near by:

• geothermal heat/geothermal heat technology: 'is about' some ('geothermal heat plant' and 'participates in' some 'geothermal heat transfer') --> geothermal heat plant or unit or both?
• solarthermal heat/solarthermal heat technology: 'is about' some ('solar heat plant' and 'participates in' some 'solar thermal energy transformation') --> solar heat plant or unit or both?

heat pump (technology) an the others are more tricky: 'is about' some ('electric heat pump' and 'participates in' some 'heat transfer')

• The axiom like this seems a little too unspecific for heat pumps. I opened #1595
• Also p2h and hybrid boiler technology would require such a process, see #1570

[l-emele]

Regarding the plant versus unit question: I had the same question when implementing wind power technology and its subclasses. For wind power technology itself I have currently only the unit in the axiom:

• 'is about' some 'wind energy converting unit' and ('participates in' some 'wind energy transformation')

But for offshore wind power technology versus onshore wind power technology I used additionally the plant to distinguish between those two classes:

• 'is about' some ('wind energy converting unit' and ('part of' some 'offshore wind farm')) and ('participates in' some 'wind energy transformation')
• 'is about' some ('wind energy converting unit' and ('part of' some 'onshore wind farm')) and ('participates in' some 'wind energy transformation')

heat pump (technology) an the others are more tricky: 'is about' some ('electric heat pump' and 'participates in' some 'heat transfer')

While in "normal" heat transfers, the thermal energy flows from the higher to the lower temperature. In contrast, in heat transfers involving heat pumps the thermal energy flows from lower to higher temperatures. Maybe we need additional subclasses of heat transfer with normal versus reversed heat flow.

[l-emele]

For solar power technology I have to options to axiomatise the process part:

• 'participates in' some ('electricity generation process' and ('has energy input' some 'solar energy'))
• 'participates in' some ('solar energy transformation' and ('has physical output' some 'electrical energy'))

Both are equivalent, currently I use the first one. Did you have also axioms where you can basically choose between to equivalent axioms without one being better than the other?

[l-emele]

Regarding the plant versus unit question: I had the same question when implementing wind power technology and its subclasses.

I noted: Given that energy technology has the axiom 'is about' some ('energy transformation unit' and ('participates in' some 'energy transformation')), the unit must be included in the subclasses, else the reasoner in Protégé shows errors.

[l-emele]

I made quite some substantial progress with the power generation technologies:

I just pushed these changes and opened PR #1601 as draft where the changes can be seen.

[stap-m]

I think it makes sense to finish #1527 soon. We are axiomatising the classes here that are being restructures there...

[stap-m]

Heat technologies still wait for some issues.

I started with the ptx technologies now to make some progress. Here, hierarchy and axioms are more or less straight forward:

• fuel generation technology as subclass of energy technology
  • power-to-x technology as subclass of fuel generation technology
    • power-to-gas technology as subclass of power-to-x technology
      • power-to-ammonia technology as subclass of power-to-gas technology
      • power-to-methane technology as subclass of power-to-gas technology
    • power-to-liquid technology as subclass of power-to-x technology

'power-to-fuel technology' 'is about' some ('power-to-fuel system' and 'participates in' some power-to-fuel process) 'power-to-gas technology' 'is about' some ('power-to-gas system' and 'participates in' some power-to-gas process) 'power-to-ammonia technology' 'is about' some ('power-to-annonia system' and 'participates in' some power-to-ammonia process) etc.

[stap-m]

For the scenario bundles it is important to continue here rather soon. Missing is still

• [x] storage technologies
• [x] mobility technologies
• [ ] non-energetic use for energy carriers --> #1773
• [ ] heat technologies --> #1772

[stap-m]

From bilateral meeting with @l-emele

Storage technologies:

• create X energy storage objects as equivalent class via X energy storage function
• general energy storage technology
• X energy storage technology
  • first level of inferred hierarchy into OEKG

Mobility technologies:

• introduce mobility technology and electric vehicle mobility technology

[stap-m]

CCS technology is being discussed in #1760

[stap-m]

I opened seperate issues for non-energetic use for energy carriers and heat technologies and close here.