`Fuel` and `EndUse` fields in `Technodata.csv` aren't/shouldn't be required

[tsmbland]

The purpose of these fields (in theory) is so that the fueltype and same_enduse search spaces can filter technologies that have the same fuel/enduse.

However, we already know what the fuel and enduse of all the technologies are based on the CommIn and CommOut files, so these columns in the Technodata file shouldn't be necessary.

In fact, same_enduse doesn't actually use the EndUse field (despite what the documentation says), and determines end-use based on outputs defined in the CommOut file (along with the is_enduse filter which excludes environmental commodities)

I suggest we do a similar thing for fueltype, and then we can drop both of these fields from the Technodata file

[Jin-Jun-Mei]

I have a related comment regarding the "Fuel" column in the Technodata.csv.

If the "Fuel" column in Technodata.csv is no longer used, a potential improvement could be allowing a technology or process to use multiple fuels (for example, a boiler can run on either solar or gas). I guess this function is already exist, but since the Technodata.csv currently only allows one input in the "Fuel" column per process, it looks like it limits each technology to a single fuel type.

From what I understand, we can define more than one input fuel for a technology/process in the CommIn.csv.

/Jinxi