Review of various cost methods

[kndehaan]

Currently, the ETM generally makes use of two cost methods:

1. Mece cost methods These are composed of the capital_expenditures_excluding_ccs_per and operating_expenses_excluding_ccs_per methods for production technologeis. Fuel costs are not accounted for within this cost method. This cost method calculates the system costs.

2. Levelised production cost methods This method is applied in certain charts or tables that use the total_costs_per method, consisting of among others the variable_costs_per_typical_input, which does take into account the weighted_carrier_cost_per_mj (and thus the fuel costs).

• [ ] Assuming that the mece system cost method is the main method, it should be clearly stated whenever is deviated from this method (e.g. queries for levelised production costs charts). Both for the user as well as in the query files.
• [ ] It would be good te review the names of the costs methods or components within the costs methods. For instance, of cost method 2 the variable_costs_per_typical_input does include weighted_carrier_cost_per_mj. Whereas of cost method 1, operating_expenses_excluding_ccs_per is constructed as depicted below, where the name variable_operation_and_maintenance_costs is very similar to that of cost method 2. It should become more clear with which method the weighted_carrier_cost_per_mj is included or not.
• [ ] We should evaluate whether we need a new hourly electricity cost method that calculates the electricity costs on hourly basis rather than the hourly electricity price or determining electricity costs on annual basis (comparable to hydrogen).

def operating_expenses_excluding_ccs
        fetch(:operating_expenses_excluding_ccs) do
          variable_operation_and_maintenance_costs -
            variable_operation_and_maintenance_costs_for_ccs +
            fixed_operation_and_maintenance_costs_per_year
        end
      end