A quick question to further understand INPUT and SHARE-IN

[[email protected]]

Hi,


I’m a bit confused about the practical differences between the two approaches, even though I understand their setups:

1. Setting the INPUT (UP) constraint for auxiliary energy inputs for specific processes as the table shown below;
   


2. Using SHARE-IN for each energy type (with the same values as in INPUT), given the sum of SHARE-IN can exceed 1 when lim_type=UP
   . And we set EFF=1.Could you help clarify how their effects differ, especially when I introduce higher cost penalties or carbon taxes on fossil fuel sources?

Best,
Xiao

[Antti-L]

> Using SHARE-IN for each energy type (with the same values as in INPUT), given the sum of SHARE-IN can exceed 1 when lim_type=UP. And we set EFF=1. Could you help clarify how their effects differ, especially when I introduce higher cost penalties or carbon taxes on fossil fuel sources?

I think the main effect is that using SHARE-IN for each energy commodity with the same values as for INPUT would not make sense. SHARE-IN defines a genuine share in the total inputs of the same type (NRG), and therefore the maximum achievable share is 1.  Using EFF=1 would force the total energy input equal to the activity (i.e. the total energy input would be 1.0 per unit of activity), while in reality, for example in AT the total energy input should be 7.70 per unit of activity (based on the sum of the energy INPUTs). As you see, the effects would differ in a good way with respect to high carbon taxes, but would not be at all realistic. A possible small step closer to reality would be to define EFF=1/7.7 for AT.

Note also that INPUT implicitly creates the topology here (in the JRC-EU-TIMES). If you would just replace INPUT with SHARE-IN, you would actually have no inputs at all, unless you would explicitly define the topology.

[[email protected]]

> Using SHARE-IN for each energy type (with the same values as in INPUT), given the sum of SHARE-IN can exceed 1 when lim_type=UP. And we set EFF=1. Could you help clarify how their effects differ, especially when I introduce higher cost penalties or carbon taxes on fossil fuel sources?

I think the main effect is that using SHARE-IN for each energy commodity with the same values as for INPUT would not make sense. SHARE-IN defines a genuine share in the total inputs of the same type (NRG), and therefore the maximum achievable share is 1.  Using EFF=1 would force the total energy input equal to the activity (i.e. the total energy input would be 1.0 per unit of activity), while in reality, for example in AT the total energy input should be 7.70 per unit of activity (based on the sum of the energy INPUTs). As you see, the effects would differ in a good way with respect to high carbon taxes, but would not be at all realistic. A possible small step closer to reality would be to define EFF=1/7.7 for AT.

Note also that INPUT implicitly creates the topology here (in the JRC-EU-TIMES). If you would just replace INPUT with SHARE-IN, you would actually have no inputs at all, unless you would explicitly define the topology.

Hi Antti,

Thank you for the valuable response. Just a follow up, how do you differentiate the efficiency among different sources (electricity, gas, hydrogen) when you are using INPUT [it seems the input values are absolute if output demands are set, and the efficiency only implicitly involved into that attribute]: for example, using electricity can produce IRON more efficiently than oil/gas, so how to differentiate/redefine them?

Best,
Xiao

[Antti-L]

I am not quite able to follow the ideas behind your question.

The INPUT attribute simply defines the amount of input flow per unit of activity.  So, if you have inputs Com1, Com2, …, ComN such that the process consumes the amount of A1 of Com1 per unit of activity, the amount of A2 of Com2 per unit of activity, … , and the amount of AN of ComN per unit of activity, then you can simply define:

  INPUT(r,y,p,COM1) = A1;
  INPUT(r,y,p,COM2) = A2;
  […]
  INPUT(r,y,p,COMN) = AN;

That is exactly what the INPUT attributes defined for the IISFINPRO00 process shown above are accomplishing. Their main purpose is to produce the correct energy balance for the existing steel finishing process. The total energy consumption per unit of activity is thus the sum of the INPUT values.  Only in a rather "loosely speaking" meaning, you could also say that the efficiency of producing activity by using COM1 is 1/A1, and the efficiency of producing activity by using COM2 is 1/A2,…, and the efficiency of producing activity by using COMN is 1/AN.  But using such statements may give the false impression that COM1, COM2,..., COMN would be substitutable, with substitution ratios given by those “efficiencies”.  However, that would certainly not be true here, because the energy balance of the finishing process, as defined by the INPUTs, is simply based on the actual consumption data for the existing installations in each country. Any technical input substitution ratios should be estimated in a completely different way, and then you could define commodity-specific ACT_EFF parameters based on them, as well as FLO_SHAR parameters to restrict the substitution possibilities with realistic bounds. In many cases the possibilities for substitution e.g. between fuels and electricity may actually be quite limited in the existing technology stock. In fact, it looks like the JRC-EU model has chosen to include no substitution possibility at all during the lifetime, which is indeed a very conservative assumption. But note that by allowing early retirements, one could let the model replace the existing process with new technologies using quite different energy inputs.

> it seems the input values are absolute if output demands are set

Could you please explain what you mean by that?  If we have INPUT=A1 for input Com1, the input flow of Com1 is A1 × Activity.  The flow is therefore proportional to the Activity, with the proportionality multiplier A1. The value of INPUT is thus a multiplier of the activity, like efficiencies are (usually) multipliers of flows.

[Antti-L]

> Just a follow up, how do you differentiate the efficiency among different sources (electricity, gas, hydrogen) when you are using INPUT

To follow-up, can you clarify what you mean by differentiating the efficiency among different sources when using INPUT?  Wouldn't an efficiency define a relation between the input flows and the activity or the primary output?  Don't you think that the INPUT parameter by itself defines such a relation between each input flow and the activity, those relations being differentiated for each input flow insofar as the INPUT values are different?

[[email protected]]

> Just a follow up, how do you differentiate the efficiency among different sources (electricity, gas, hydrogen) when you are using INPUT

To follow-up, can you clarify what you mean by differentiating the efficiency among different sources when using INPUT?  Wouldn't an efficiency define a relation between the input flows and the activity or the primary output?  Don't you think that the INPUT parameter by itself defines such a relation between each input flow and the activity, those relations being differentiated for each input flow insofar as the INPUT values are different?

Hi,

Thanks for the follow-up. You're right—INPUT is essentially the inverse of efficiency, so it conveys similar information. My question is: if a single process has fixed INPUT values for multiple energy sources (e.g., electricity, gas), does that limit the model's ability to select the most efficient option (such as favoring electricity over gas), since the relative efficiencies are already hardcoded?

Best,
Xiao

[Antti-L]

> My question is: if a single process has fixed INPUT values for multiple energy sources (e.g., electricity, gas), does that limit the model's ability to select the most efficient option (such as favoring electricity over gas), since the relative efficiencies are already hardcoded?

Yes, of course it limits.  If you wish to model substitution between the energy inputs of a technology, you should use a flexible input group instead, defined with either (commodity-specific) ACT_EFFs, optionally together with a group efficiency, or with FLO_EFF parameters, and define realistic limits for substitution with e.g. FLO_SHAR parameters, such that are technically feasible without additional investments. For a calibration year, obviously no (or little) substitution should be allowed from the calibrated base year levels of inputs.

[[email protected]]

> My question is: if a single process has fixed INPUT values for multiple energy sources (e.g., electricity, gas), does that limit the model's ability to select the most efficient option (such as favoring electricity over gas), since the relative efficiencies are already hardcoded?

Yes, of course it limits.  If you wish to model substitution between the energy inputs of a technology, you should use a flexible input group instead, defined with either (commodity-specific) ACT_EFFs, optionally together with a group efficiency, or with FLO_EFF parameters, and define realistic limits for substitution with e.g. FLO_SHAR parameters, such that are technically feasible without additional investments. For a calibration year, obviously no (or little) substitution should be allowed from the calibrated base year levels of inputs.

Hi Antti,

Thank you for the response. I never tried FLO_EFF, I will give it a try.

Best,
Xiao

[Antti-L]

An additional suggestion for modeling energy input substitution would be to model retrofitting options for such aggregated existing processes. For example, this IISFINPRO00 process appears to have been defined with an (unrealistic) lifetime of 100 years, and therefore it may have a notable cost advantage against investing in completely new process alternatives. But by adding retrofit options, one could model the possibilities of e.g. electrifying and/or improving the energy efficiency of this process, taking into account appropriate retrofitting costs involved. I think that might be a good approach in many cases like this.

[[email protected]]

An additional suggestion for modeling energy input substitution would be to model retrofitting options for such aggregated existing processes. For example, this IISFINPRO00 process appears to have been defined with an (unrealistic) lifetime of 100 years, and therefore it may have a notable cost advantage against investing in completely new process alternatives. But by adding retrofit options, one could model the possibilities of e.g. electrifying and/or improving the energy efficiency of this process, taking into account appropriate retrofitting costs involved. I think that might be a good approach in many cases like this.

Hi,

Thanks for the helpful suggestions. 

Best,
Xiao