6a. Tutorial - Optimal Capacity Expansion

Investment decisions in backbone need various input data. In this file the different parameters are explained.

• Investment Costs: Investment Costs are the investment, that has to be made when first installing the powerplant. They usually have the unit currency/MW
• Fixed operation and maintenance costs: Fixed operation and maintenance costs (FOM costs) are costs which must be paid each year the unit is operating. They usually have the unit currency/MW/a.
• Annuity: The annuity describes the amount of investment costs that is to be repaid each year. It is calculated by multiplying the annuity factor with the investment costs. The annuity factor is influenced by the lifetime of the plant and the discount rate. It is calculated by:
  
  with discount rate r and unit lifetime lifetime.
• Integer Investment: When using integer investment, the number of investment units must be an integer. For example, with a unit size for the gas turbine of 50 MW, only an investment of 50 MW/100 MW/150 MW etc. is possible. When using continuous investment, also all numbers in between are possible. Integer investment is closer to reality (you cannot build a gas turbine with a capacity of 0.01 MW) but need more computational resources.