`technical_lifetime` not defined for historical vintages in Westeros tutorial

[volker-krey]

Problem description

The technical_lifetime lifetime parameter for historical vintages of the power plant (and bulb) technologies is not defined. Usually, this issue does not cause a problem with running the Westeros tutorial, because the message_ix takes the technical_lifetime of the first_period when constructing the set map_tec_lifetime:

message_ix/message_ix/model/MESSAGE/data_load.gms

Line 129 in b572cce

< sum(first_period, technical_lifetime(node,tec,first_period) ) ) = yes ;

However, for #451 the absence of the technical_lifetime of historical vintages causes problems and would thus be beneficial to correct (probably as part of this PR). This problem arises as a result of the year_vtg set in of technical_lifetime being defined over model_horizon:

message_ix/tutorial/westeros/westeros_baseline.ipynb

Line 748 in b572cce

" year_vtg=model_horizon,\n",

Suggested solution

My understanding is that an easy fix is to define technical_lifetime over the set vintage_years as used for the parameters input and output:

message_ix/tutorial/westeros/westeros_baseline.ipynb

Line 481 in b572cce

" year_vtg=vintage_years,\n",

It would be beneficial to discuss the approach as this may have other implications.