This folder contains the models used in the CBA of the proposed new TPM (2021) and the summary results of the modelling.

The files follow a very similar structure to the files released for the 2020 Guidelines CBA, at https://www.emi.ea.govt.nz/Wholesale/Datasets/_AdditionalInformation/SupportingInformationAndAnalysis/2020/20200417_TPM_CBAfilesToSupportApr2020InformationPaper. 

However, model code, data input files and modelling scenarios have been updated and changed to e.g. reflect the proposed new TPM (2021).

The models and results are discussed in:
(1) The Authority's consultation paper on the proposed new TPM published on 8 October 2021 (https://www.ea.govt.nz/assets/dms-assets/28/ProposedTransmission-Pricing-Methodology-Consultation-paper-v3.pdf)
(2) The Technical paper for the 2021 CBA of the proposed TPM ('CBA approach, methods and assumptions: Proposed TPM 2021, Technical paper)

The summary of results is in the folder 'Summary'. The results in this folder are the key results drawn on in (1).

The models are contained in the 'Grid use model' folder and the 'Investment efficiencies' folder. Information in (2) explains the modelling frameworks, input data and assumptions. 

The file "List of files.xlsx', alongside this 'About.txt' file, lists all files that are being released and explains their purpose/contents.

There are also 'About.txt' files in the 'Grid use model' and 'Investment efficiencies' folders explaining the content of those folders. 


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Update to modelling files 29 October 2021

We have made a change to the proposed TPM consultation paper, replacing a graph relating to modelled investment in generation (Figure 24 on page 148) 
with a new version and also replacing some supporting files for the CBA on the EMI website. The new graph and supporting files reflect a correction to the underlying data processing.

The change corrects an overstatement of annual investment in generation. The overstatement comes from the file called 'Investment.py', which collated model results based on an index consisting of plant names, peak capacity and capex. 
The code counted plant with declining capex multiple times as if it were a new investment each time capital costs change.
 
The corrections affect only the calculations of summary values for investment/capex by scenario and no other values.
 
The file "List of files" includes a sheet called "Files updated 28 October" that were updated.

The subset of folders published on EMI on 20 October have been relabeled as "Output_original" and "Summary_original". The python file published on 20 October has been relabeled "Investment_original.py"