Refinery Alternatives

[JozefO]

Hello guys how you deal with Refinery modelling ? 

I have some questions in my VT_file, please see attached. 

Thanks for all tips, advices or observations.

[Antti-L]

As no-one has responded, maybe I can make some small observations:

The EFF and CEFF parameters in VEDA are converted into ACT_EFF parameters for TIMES.  ACT_EFF defines how much activity is produced per 1 unit of flows, usually per 1 unit of input flows.  The flows to be included are determined from the so-called shadow group associated with every ACT_EFF parameter. The shadow group can be explicitly specified by defining ACT_EFF for a genuine commodity group, and the process efficiency will be then defined over the all those members of that group which have an input flow. But if no genuine group is specified, but only individual commodities, the shadow group is by default the commodity type of the commodity specified in ACT_EFF.  And finally, if no commodity is specified either, then the shadow group will be the default shadow group of the whole process (see the documentation). Within the shadow group, each member will by default have the efficiency defined for the group, unless there is an ACT_EFF defined for the commodity itself, which would act as a multiplier.  And the group efficiency has a default of 1.  Hence, by defining a value of zero one can also effectively exclude some members of the group from being considered.

As you can see, ACT_EFF is a flexible and easy-to-use parameter for defining process efficiencies involving multiple commodity flows, and it is also very easy to use it for a single-input default case, by just defining ACT_EFF(ACT).  And under VEDA, one can also automatically exclude any input flows from the efficiency shadow groups by defining them as auxiliary input flows. FLO_EFF is another powerful and flexible way of defining efficiencies/relations, basically between any process flows, not just between input flows and the activity.

Now, if we look at your refinery process, we can see that it has only a single ACT_EFF-related efficiency parameter, CEFF-I(SUPCOIL)=2.479.  Here, SUPCOIL is apparently an NRG commodity representing the crude oil input. Therefore, the shadow group would be NRG, but with any flows defined as auxiliary in VEDA excluded.  It therefore seems that the group will be {SUPCOIL, ELCD, COHT} (assuming these are all NRG; the commodity type information is missing).  Assuming furthermore that the PCG of the process consists of the oil products refined, the resulting process efficiency will thus be 248% from crude oil to oil-products, or 100% from electricity or heat to oil-products, the input mix of these three being flexible. These look quite strange efficiencies to me, especially the efficiency from refining crude oil to oil products looks astonishing, but also letting it produce oil products from electricity or heat instead of the crude feed-stock looks incorrect.

Anyway, whatever the overall efficiency is between the refinery feedstocks (SUPCOIL here) and the oil-products (and any aux outputs), I think the carbon balance (between the carbon in the inputs and in the outputs) should be enforced. I am myself always defining a carbon balance equation for my refinery processes, where the carbon content in the feedstocks is required to be greater than or equal to the carbon in the outputs (main+auxiliary), and any excess carbon input is then accounted as process CO2 emissions. The balance is easy to define with e.g. FLO_EMIS parameters, using a dummy flow for the excess carbon.