add truck costs and transmission flow

[Betristor]

Add truck costs into writing hydrogen costs and add a writing function for reporting transmission flow through pipelines and trucks.

[Betristor]

@RuaridhMacd @anna-nadia This branch added some code for reporting truck costs and writing hydrogen transmission flow through pipelines and trucks in a single file. I adjusted trucks' costs to see whether trucks could be of any use. When a scenario has trucks in operation, it seems ok with all truck outputs including capacities, states, transits and hydrogen flow through trucks. I think the truck module is ready to go.

[anna-nadia]

This all looks fine to me. So the new file "transmission flow" is basically a combination of the pipeline flow + truck flow files? Regarding truck costs, we should discuss on the side about compression. The naming is a bit confusing when comparing to storage, where we use "charge" to talk about compression costs (rather than energy). Also compression costs are typically given per (tonne/hour) but here we are using per tonne. I understand that we needed to do this because trucks themselves are parameterized in tonnes. Anyhow, the compression cost should be very low if it is parameterized per tonne - maybe we should call this a variable cost? I assume we are looking at tonnes compressed over the compressor lifetime.

[Betristor]

This all looks fine to me. So the new file "transmission flow" is basically a combination of the pipeline flow + truck flow files? Regarding truck costs, we should discuss on the side about compression. The naming is a bit confusing when comparing to storage, where we use "charge" to talk about compression costs (rather than energy). Also compression costs are typically given per (tonne/hour) but here we are using per tonne. I understand that we needed to do this because trucks themselves are parameterized in tonnes. Anyhow, the compression cost should be very low if it is parameterized per tonne - maybe we should call this a variable cost? I assume we are looking at tonnes compressed over the compressor lifetime.

@anna-nadia Yes, the transmisson file conbines hydrogen flow form trucks and pipelines into one single file on zone level, detailed pipe level or truck level flows are seperated in corresponding files.
As for cost terms of hydrogen trucks, the name space is truly confusing. Energy is used for compression and charge is used for truck capacity. This will be modified in later development to make name space more sorted and clear.