Require demand entries for every milestone year

[alexdewar]

This is half bug report, half question. If anyone can shed any light, that would be appreciated!

According to the model description:

Service demands must be given a value for the base time period and all milestone time periods in each region.

Am I to take it from that that, for example, if your milestone years are 2020 and 2030, there should be two entries in demand.csv for every combination of region and commodity, one for each? I'm just not sure if that's what's meant by the phrase "milestone time periods".

If so, I think we'll need to:

• Add a check for this when reading in demand
• Update the example demand.csv file, as it currently only has one entry, although there are two milestone years

Thoughts? @dalonsoa @tsmbland @ahawkes

[tsmbland]

MUSE1 will interpolate with flat-forward extension if a year isn't specified. So, in this case, 2030 would be given the same demand as 2020.

I imagine we'll want to do something similar here in the long run (also assuming zero demand if a commodity/region combination isn't included at all). @ahawkes can correct me if I'm wrong.

Probably something we can come back to later though as it's more of a user experience thing, so maybe for now we should just mandate that every year is specified, as you've suggested.

[alexdewar]

Ah ok! That makes sense.

I think your suggestion to come back to it later is a good one, as we might not want to replicate the MUSE1 behaviour exactly. So, for now, let's just require demand to be specified for every milestone year.