Fuel price and annual fuel price change might not be implemented correctly #172
Description
Simulations of @a-linke and @KatLamm indicate some wierd behavior if the annual fuel price is not set to 0 and even if it is, then diesel is massively preferred in defavor of other technologies, which is not expected.
The only use of the input variabe FUEL_PRICE_CHANGE_ANNUAL is in the module D0:
offgridders/src/D0_process_input.py
Line 170 in 54d80b2
It is then used in the function present_value_of_changing_fuel_price
In the function call (that I copied under for convenience):
present_value_changing_fuel_price = economics.present_value_of_changing_fuel_price(
fuel_price=experiment[FUEL_PRICE],
project_lifetime=experiment[PROJECT_LIFETIME],
wacc=experiment[WACC],
crf=experiment[CRF],
fuel_price_change_annual=experiment[FUEL_PRICE_CHANGE_ANNUAL],
)
it seems that all arguments stem directly from input variables from the .xlsx file.
Whatever comes out of the function present_value_of_changing_fuel_price is then reassigned to the variable PRICE_FUEL (note that it is not FUEL_PRICE)
Looking into the function, one can see that if fuel_price_change_annual is set to 0, then what comes out of the function present_value_of_changing_fuel_price should be exactly equal to the what value was provided to the argument fuel_price
The variable PRICE_FUEL is then used to compute the EXPENDITURES_FUEL_ANNUAL (results):
offgridders/src/G3a_economic_evaluation.py
Line 393 in 3c3349c
As well as the variable_costs of the fuel energy source:
It is given by
experiment[PRICE_FUEL]/ experiment[COMBUSTION_VALUE_FUEL]experiment[PRICE_FUEL] has unit currency/unit and experiment[COMBUSTION_VALUE_FUEL] kWh/unit so the variable_costs have unit currency/kWh as expected (one unit is for example one gallon, or one liter)