Battery storage double check

[Ryo Ishida]

Hi all,

I'd like you to double check how to model the storage.

I intend to model 4-hour storage batteries and input the unit cost per kW.
I understand AFC(NRG) to be the input and output capacity per GW and AFC(ACT) to be the ratio of GWh to 24 hours.
Also, I understand that AFC(NRG) to be the input and AFC(ELC) to be the output capacity, is that correct?
Also, I understand that AFAC is the upper limit of the yearly utilisation rate of storage, is that correct?

Please inform if there is anything wrong.
Thank you

Ryo

[Antti-L]

> I understand that AFC(NRG) to be the input and AFC(ELC) to be the output capacity, is that correct?

Strictly speaking, AFC(NRG) defines an availability factor for the storage input and output flows, and if ELC is an output flow, AFC(ELC) defines an availability factor for the storage output flow (overriding AFC(NRG) for the output). In addition, with either of these, the storage capacity will represent the nominal maximum output level. But I guess your statement can be understood to be consistent with all that. The storage energy capacity can in this case be defined in proportion to the output capacity, by using NCAP_AFC(ACT), like you mentioned.

> I understand that AFAC is the upper limit of the yearly utilisation rate of storage, is that correct?

In general, NCAP_AFAC(r,y,p,com) defines an ANNUAL commodity-specific utilization factor. But yes, in your storage case, NCAP_AFAC(r,y,p,ELC) would define a maximum ANNUAL utilization factor for the output capacity of the storage.

[Ryo Ishida]

Hello Antti-L san

Thank you for your instruction.
Please let me ask you for a basic question.

I think NRG and ACT here are commodity groups, what do they mean respectively?

Thank you in advance.

Ryo

[Antti-L]

Ah, yes.  'NRG' is the group containing all NRG commodities.  For storage availability factors, this group can be used in NCAP_AFC/AFAC for including all the storage charging/discharging flows of type NRG into the availability equation, like described above.

'ACT' is a reserved name for the activity-defining group of a process. As a reserved commodity group label, 'ACT' cannot be defined by the user as a commodity in the RES topology.  There are basically no other reserved commodity group / commodity names other than ACT and the commodity types. 'ACT' can be used as a CG in the following TIMES attributes: ACT_EFF, FLO_EMIS, FLO_EFF, FLO_SHAR, FLO_CUM, IRE_FLOSUM, NCAP_AFC, PRC_ACTFLO, STG_SIFT (and FLO_FUNCX). For example, NCAP_AFC(r,y,p,'ACT',tsl) can be used for defining an availability factor for the storage activity (of storage processes), ACT_EFF(r,y,p,'ACT',ts) can be used for defining a process efficiency from the shadow primary group (SPG) to the activity (normal processes), and FLO_EMIS(r,y,p,'ACT',com,ts) can be used for defining an emission factor for emissions com in proportion to the process activity. The exact meaning of 'ACT' thus varies according to the attribute where it is used, as described in the documentation.

[Ryo Ishida]

Thank you for your instruction.

I understood!