Economic Parameters

Table: Economic Model Parameters
Parameter Unit Description
\(j\) _ Global Discount Rate
\(D_y\) _ Factor for any Payment Made in Modeled Year y
\(I_y\) _ Factor for any Investment Made in Modeled Year y
\(\overline{L}_{\text{cost}}\) Maximum Total System Costs (if CO2 is minimized)
Commodity Economic Parameters
\(k_{yvc}^\text{fuel}\) €/MWh Stock Commodity Fuel Costs
\(k_{yvc}^\text{env}\) €/MWh Environmental Commodity Costs
\(k_{yvct}^\text{bs}\) €/MWh Buy/Sell Commodity Buy/Sell Costs
\(k_{yvc}^\text{bs}\) _ Multiplier for Buy/Sell Commodity Buy/Sell Costs
Process Economic Parameters
\(i_{yvp}\) _ Weighted Average Cost of Capital for Process
\(z_{yvp}\) a Process Depreciation Period
\(k_{yvp}^\text{inv}\) €/MW Process Capacity Investment Costs
\(k_{yvp}^\text{fix}\) €/(MW a) Annual Process Capacity Fixed Costs
\(k_{yvp}^\text{var}\) €/MWh Process Throughput Variable Costs
Storage Economic Parameters
\(i_{yvs}\) _ Weighted Average Cost of Capital for Storage
\(z_{yvs}\) a Storage Depreciation Period
\(k_{yvs}^\text{p,inv}\) €/MW Storage Power Investment Costs
\(k_{yvs}^\text{p,fix}\) €/(MW a) Annual Storage Power Fixed Costs
\(k_{yvs}^\text{p,var}\) €/MWh Storage Power Variable Costs
\(k_{yvs}^\text{c,inv}\) €/MWh Storage Size Investment Costs
\(k_{yvs}^\text{c,fix}\) €/(MWh a) Annual Storage Size Fixed Costs
\(k_{yvs}^\text{c,var}\) €/MWh Storage Usage Variable Costs
Transmission Economic Parameters
\(i_{yvf}\) _ Weighted Average Cost of Capital for Transmission
\(z_{yaf}\) a Tranmission Depreciation Period
\(k_{yaf}^\text{inv}\) €/MW Transmission Capacity Investment Costs
\(k_{yaf}^\text{fix}\) €/(MW a) Annual Transmission Capacity Fixed Costs
\(k_{yaf}^\text{var}\) €/MWh Tranmission Usage Variable Costs

Discount Rate, \(j\), m.global_prop.xs('Discount rate', level=1).loc[m.global_prop.index.min()[0]]['value']: The discount rate \(j\) is used to calculate the present value of future costs. It is set in the worksheet “Global” in the input file of the first support timeframe.

Factor for Future Payments, \(D_y\): The parameter \(D_y\) is a multiplier that has to be factored into all cost terms apart from the invest costs in intertemporal planning based on support timeframes. All other cost terms for the support timeframe \(y\) are muliplied directly with this factor to find the present value of the sum of costs in support timeframe \(y\) and all non-modeled time frames until the next modeled time frame \(y_{+1}\), which are identical to the support timeframe with the modeling approach taken:

\[D_y=(1+j)^{1-(y-y_{\text{min}})}\cdot \frac{1-(1+j)^{-(y_{+1}-y+1)}}{j}\]

In script modelhelper.py the factor \(D_y\) is implemented as the product of the functions:

def discount_factor(stf, m):
    """Discount for any payment made in the year stf
    """
    discount = (m.global_prop.xs('Discount rate', level=1)
                .loc[m.global_prop.index.min()[0]]['value'])

    return (1 + discount) ** (1 - (stf - m.global_prop.index.min()[0]))

and

def effective_distance(dist, m):
    """Factor for variable, fuel, purchase, sell, and fix costs.
    Calculated by repetition of modeled stfs and discount utility.
    """
    discount = (m.global_prop.xs('Discount rate', level=1)
                .loc[m.global_prop.index.min()[0]]['value'])

    if discount == 0:
        return dist
    else:
        return (1 - (1 + discount) ** (-dist)) / discount

Factor for Investment Made in Support Timeframe y, \(I_y\): The parameter \(I_y\) is a multiplier that has to be factored into the invest costs in intertemporal planning based on support timeframes. The book value of the total invest costs per capacity in support timeframe \(y\) is muliplied with this factor to find the present value of the sum of costs of all annual payments made for this investment within the modeling horizon. The calculation of this parameter requires several case distinctions and is given by:

  • \(i\neq0,~j\neq0\):
\[I_{y}=(1+j)^{1-(y-y_{\text{min}})}\cdot \frac{i}{j}\cdot \left(\frac{1+i}{1+j}\right)^n\cdot \frac{(1+j)^n-(1+j)^{n-k}}{(1+i)^n-1}\]
  • \(i=0,~j=0\):

    \[I_{y}=\frac{k}{n}\]
  • \(i\neq0,~j=0\):

    \[I_{y}=k\cdot\frac{(1+i)^n\cdot i}{(1+i)^n-1}\]
  • \(i=0,~j\neq0\):

    \[I_{y}=\frac 1n \cdot (1+j)^{1-(y-y_{\text{min}})}\cdot \frac{(1+j)^k-1}{(1+j)^k\cdot j}\]

where \(k\) is the number of annualized payments that have to be made within the modeling horizon, \(n\) the depreciation period and \(i\) the weighted average cost of capital. Note that the parameters \(i\) and \(n\) take different values for different unit tuples.

In script modelhelper.py the factor \(I_y\) is implemented with the function:

def invcost_factor(dep_prd, interest, discount=None, year_built=None,
                   stf_min=None):
    """Investment cost factor formula.
    Evaluates the factor multiplied to the invest costs
    for depreciation duration and interest rate.
    Args:
        dep_prd: depreciation period (years)
        interest: interest rate (e.g. 0.06 means 6 %)
        year_built: year utility is built
        discount: discount rate for intertmeporal planning
    """
    # invcost factor for non intertemporal planning
    if discount is None:
        if interest == 0:
            return 1 / dep_prd
        else:
            return ((1 + interest) ** dep_prd * interest /
                    ((1 + interest) ** dep_prd - 1))
    # invcost factor for intertemporal planning
    elif discount == 0:
        if interest == 0:
            return 1
        else:
            return (dep_prd * ((1 + interest) ** dep_prd * interest) /
                    ((1 + interest) ** dep_prd - 1))
    else:
        if interest == 0:
            return ((1 + discount) ** (1 - (year_built-stf_min)) *
                    ((1 + discount) ** dep_prd - 1) /
                    (dep_prd * discount * (1 + discount) ** dep_prd))
        else:
            return ((1 + discount) ** (1 - (year_built-stf_min)) *
                    (interest * (1 + interest) ** dep_prd *
                    ((1 + discount) ** dep_prd - 1)) /
                    (discount * (1 + discount) ** dep_prd *
                    ((1+interest) ** dep_prd - 1)))

In this formulation also payments after the modeled time horizon are being made. To fix this the overpay is subtracted via:

def overpay_factor(dep_prd, interest, discount, year_built, stf_min, stf_end):
    """Overpay value factor formula.
    Evaluates the factor multiplied to the invest costs
    for all annuity payments of a unit after the end of the
    optimization period.
    Args:
        dep_prd: depreciation period (years)
        interest: interest rate (e.g. 0.06 means 6 %)
        year_built: year utility is built
        discount: discount rate for intertemporal planning
        k: operational time after simulation horizon
    """

    op_time = (year_built + dep_prd) - stf_end - 1

    if discount == 0:
        if interest == 0:
            return op_time / dep_prd
        else:
            return (op_time * ((1 + interest) ** dep_prd * interest) /
                    ((1 + interest) ** dep_prd - 1))
    else:
        if interest == 0:
            return ((1 + discount) ** (1 - (year_built - stf_min)) *
                    ((1 + discount) ** op_time - 1) /
                    (dep_prd * discount * (1 + discount) ** dep_prd))
        else:
            return ((1 + discount) ** (1 - (year_built - stf_min)) *
                    (interest * (1 + interest) ** dep_prd *
                    ((1 + discount) ** op_time - 1)) /
                    (discount * (1 + discount) ** dep_prd *
                    ((1 + interest) ** dep_prd - 1)))

In case of negative values this overpay factor is set to zero afterwards.

Maximum Total System Cost, \(\overline{L}_{\text{cost}}\), m.res_global_cost_limit: This parameter restricts the total present costs over the entire modeling horizon. It is only sensible and active when the objective is a minimization of CO2 emissions.

Commodity Economic Parameters

Stock Commodity Fuel Costs, \(k_{yvc}^\text{fuel}\), m.commodity_dict['price'][c]: The parameter \(k_{yvc}^\text{fuel}\) represents the book cost for purchasing one unit (1 MWh) of a stock commodity \(c\) (\(\forall c \in C_\text{stock}\)) in modeled timeframe \(y\) in a site \(v\) (\(\forall v \in V\)). The unit of this parameter is €/MWh. The related section for this parameter in the spreadsheet belonging the support timeframe \(y\) can be found in the “Commodity” sheet. Here each row represents another commodity tuple \(c_{yvq}\) and the column of stock commodity tuples (\(\forall q = "Stock"\)) in this sheet with the header label “price” represents the corresponding parameter \(k_{yvc}^\text{fuel}\).

Environmental Commodity Costs, \(k_{yvc}^\text{env}\), m.commodity_dict['price'][c]: The parameter \(k_{yvc}^\text{env}\) represents the book cost for producing/emitting one unit (1 t, 1 kg, …) of an environmental commodity \(c\) (\(\forall c \in C_\text{env}\)) in support timeframe \(y\) in a site \(v\) (\(\forall v \in V\)). The unit of this parameter is €/t (i.e. per unit of output). The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) is the “Commodity” sheet. Here, each row represents a commodity tuple \(c_{yvq}\) and the fourth column of environmental commodity tuples (\(\forall q = "Env"\)) in this sheet with the header label “price” represents the corresponding parameter \(k_{yvc}^\text{env}\).

Buy/Sell Commodity Buy/Sell Costs, \(k_{yvct}^\text{bs}\), m.buy_sell_price_dict[c[2], ][(c[0], tm)]: The parameter \(k_{yvct}^\text{bs}\) represents the cost for purchasing/selling one unit (1 MWh) of a buy/sell commodity \(c\) (\(\forall c \in C_\text{buy}\))/(\(\forall c \in C_\text{sell}\)) in support timeframe \(y\) in a site \(v\) (\(\forall v \in V\)) at timestep \(t\) (\(\forall t \in T_m\)). The unit of this parameter is €/MWh. The related section for this parameter in the spreadsheet can be found in the “Buy-Sell-Price” sheet. Here each column represents a commodity tuple and the row values provide the timestep information.

Multiplier for Buy/Sell Commodity Buy/Sell Costs, \(k_{yvc}^\text{bs}\), m.commodity_dict['price'][c]: The parameter \(k_{yvc}^\text{bs}\) is a multiplier for the buy/sell time series. It represents the factor on the cost for purchasing/selling one unit (1 MWh) of a buy/sell commodity \(c\) (\(\forall c \in C_\text{buy}\))/(\(\forall c \in C_\text{sell}\)) in support timeframe \(y\) in a site \(v\) (\(\forall v \in V\)). This parameter is unitless. The related section for this parameter in the spreadsheet belonging to support timeframe \(y\) can be found in the “Commodity” sheet. Here each row represents another commodity tuple \(c_{yvq}\) and the column of Buy/Sell commodity tuples (\(\forall q = "Buy/Sell"\)) in this sheet with the header label “price” represents the corresponding parameter \(k_{yvc}^\text{bs}\).

Process Economic Parameters

Weighted Average Cost of Capital for Process, \(i_{yvp}\): The parameter \(i_{yvp}\) represents the weighted average cost of capital for a process technology \(p\) in support timeframe \(y\) in a site \(v\). The weighted average cost of capital gives the interest rate (%) of costs for capital after taxes. The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Process” sheet. Here each row represents another process tuple and the column with the header label “wacc” represents the parameters \(i_{yvp}\). The parameter is given as a percentage, where “0.07” means 7%

Process Depreciation Period, \(z_{yvp}\), (a): The parameter \(z_{yvp}\) represents the depreciation period of a process \(p\) built in support timeframe \(y\) in a site \(v\). The depreciation period gives the economic and technical lifetime of a process investment. It thus features in the calculation of the invest cost factor and determines the end of operation of the process. The unit of this parameter is “a”, where “a” represents a year of 8760 hours. The related section for this parameter in the spreadsheet can be found under the “Process” sheet. Here each row represents another process tuple and the column with the header label “depreciation” represents the parameters \(z_{yvp}\).

Process Capacity Investment Costs, \(k_{yvp}^\text{inv}\), m.process_dict['inv-cost'][p]: The parameter \(k_{yvp}^\text{inv}\) represents the book value of the investment cost for adding one unit new capacity of a process technology \(p\) in support timeframe \(y\) in a site \(v\). The unit of this parameter is €/MW. To get the full impact of the investment within the modeling horizon this parameter is multiplied with the factor \(I_y\) for the investment made in modeled year \(y\). The process capacity investment cost is to be given as an input by the user. The related section for the process capacity investment cost in the spreadsheet representing the support timeframe \(y\) can be found under the “Process” sheet. Here each row represents another process \(p\) in a site \(v\) and the column with the header label “inv-cost” represents the process capacity investment costs of the corresponding process \(p\) and site \(v\) combinations.

Annual Process Capacity Fixed Costs, \(k_{yvp}^\text{fix}\), m.process_dict['fix-cost'][p]: The parameter \(k_{yvp}^\text{fix}\) represents the fix cost per one unit capacity \(\kappa_{yvp}\) of a process technology \(p\) in support timeframe \(y\) in a site \(v\), that is charged annually. The unit of this parameter is €/(MW a). The related section for this parameter in the spreadsheet correesponding to the support timeframe \(y\) can be found under the “Process” sheet. Here each row represents another process \(p\) in a site \(v\) and the column with the header label “fix-cost” represents the parameters \(k_{yvp}^\text{fix}\) of the corresponding process \(p\) and site \(v\) combinations.

Process Variable Costs, \(k_{yvp}^\text{var}\), m.process_dict['var-cost'][p]: The parameter \(k_{yvp}^\text{var}\) represents the book value of the variable cost per one unit energy throughput \(\tau_{yvpt}\) through a process technology \(p\) in a site \(v\) in support timeframe \(y\). The unit of this parameter is €/MWh. The related section for this parameter in the spreadsheet corresponding to the support timeframe \(y\) can be found under the “Process” sheet. Here each row represents another process \(p\) in a site \(v\) and the column with the header label “var-cost” represents the parameters \(k_{yvp}^\text{var}\) of the corresponding process \(p\) and site \(v\) combinations.

Storage Economic Parameters

Weighted Average Cost of Capital for Storage, \(i_{yvs}\): The parameter \(i_{yvs}\) represents the weighted average cost of capital for a storage technology \(s\) in a site \(v\) and support timeframe \(y\). The weighted average cost of capital gives the interest rate (%) of costs for capital after taxes. The related section for this parameter in the spreadsheet corresponding to the support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “wacc” represents the parameters \(i_{yvs}\) of the corresponding storage \(s\) and site \(v\) combinations. The parameter is given as a percentage, where “0.07” means 7%.

Storage Depreciation Period, \(z_{yvs}\), (a): The parameter \(z_{yvs}\) represents the depreciation period of a storage \(s\) in a site \(v\) built in support timeframe \(y\). The depreciation period gives the economic and technical lifetime of a storage investment. It thus features in the calculation of the invest cost factor and determines the end of operation of the storage. The unit of this parameter is “a”, where “a” represents a year of 8760 hours. The related section for this parameter in the spreadsheet corresponding to the support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “depreciation” represents the parameters \(z_{yvs}\) of the corresponding storage \(s\) and site \(v\) combinations.

Storage Power Investment Costs, \(k_{yvs}^\text{p,inv}\), m.storage_dict['inv-cost-p'][s]: The parameter \(k_{yvs}^\text{p,inv}\) represents the book value of the total investment cost for adding one unit new power output capacity of a storage technology \(s\) in a site \(v\) in support timeframe \(y\). The unit of this parameter is €/MW. To get the full impact of the investment within the modeling horizon this parameter is multiplied with the factor \(I_y\) for the investment made in modeled year \(y\). The related section for the storage power output capacity investment cost in the spreadsheet corresponding to the support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “inv-cost-p” represents the storage power output capacity investment cost of the corresponding storage \(s\) and site \(v\) combinations.

Annual Storage Power Fixed Costs, \(k_{yvs}^\text{p,fix}\), m.storage_dict['fix-cost-p'][s]: The parameter \(k_{yvs}^\text{p,fix}\) represents the fix cost per one unit power output capacity of a storage technology \(s\) in a site \(v\) and support timeframe \(y\), that is charged annually. The unit of this parameter is €/(MW a). The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “fix-cost-p” represents the parameters \(k_{yvs}^\text{p,fix}\) of the corresponding storage \(s\) and site \(v\) combinations.

Storage Power Variable Costs, \(k_{yvs}^\text{p,var}\), m.storage_dict['var-cost-p'][s]: The parameter \(k_{yvs}^\text{p,var}\) represents the variable cost per unit energy, that is stored in or retrieved from a storage technology \(s\) in a site \(v\) in support timeframe \(y\). The unit of this parameter is €/MWh. The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “var-cost-p” represents the parameters \(k_{yvs}^\text{p,var}\) of the corresponding storage \(s\) and site \(v\) combinations.

Storage Size Investment Costs, \(k_{yvs}^\text{c,inv}\), m.storage_dict['inv-cost-c'][s]: The parameter \(k_{yvs}^\text{c,inv}\) represents the book value of the total investment cost for adding one unit new storage capacity to a storage technology \(s\) in a site \(v\) in support timeframe \(y\). The unit of this parameter is €/MWh. To get the full impact of the investment within the modeling horizon this parameter is multiplied with the factor \(I_y\) for the investment made in modeled year \(y\). The related section for the storage content capacity investment cost in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “inv-cost-c” represents the storage content capacity investment cost of the corresponding storage \(s\) and site \(v\) combinations.

Annual Storage Size Fixed Costs, \(k_{yvs}^\text{c,fix}\), m.storage_dict['fix-cost-c'][s]: The parameter \(k_{yvs}^\text{c,fix}\) represents the fix cost per year per one unit storage content capacity of a storage technology \(s\) in a site \(v\) in support timeframe \(y\). The unit of this parameter is €/(MWh a). The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “fix-cost-c” represents the parameters \(k_{yvs}^\text{c,fix}\) of the corresponding storage \(s\) and site \(v\) combinations.

Storage Usage Variable Costs, \(k_{yvs}^\text{c,var}\), m.storage_dict['var-cost-c'][s]: The parameter \(k_{yvs}^\text{c,var}\) represents the variable cost per unit energy, that is conserved in a storage technology \(s\) in a site \(v\) in support timeframe \(y\). The unit of this parameter is €/MWh. The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Storage” sheet. Here each row represents another storage \(s\) in a site \(v\) and the column with the header label “var-cost-c” represents the parameters \(k_{yvs}^\text{c,var}\) of the corresponding storage \(s\) and site \(v\) combinations. The value of this parameter is usually set to zero, but the parameter can be taken advantage of if the storage has a short term usage or has an increased devaluation due to usage, compared to amount of energy stored.

Transmission Economic Parameters

Weighted Average Cost of Capital for Transmission, \(i_{yaf}\): The parameter \(i_{yaf}\) represents the weighted average cost of capital for a transmission \(f\) transferring commodities through an arc \(a\) built in support timeframe \(y\). The weighted average cost of capital gives the interest rate (%) of costs for capital after taxes. The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Transmission” sheet. Here each row represents another transmission \(f\) transferring commodities through an arc \(a\) and the column with the header label “wacc” represents the parameters \(i_{yaf}\) of the corresponding transmission \(f\) and arc \(a\) combinations. The parameter is given as a percentage, where “0.07” means 7%.

Transmission Depreciation Period, \(z_{yaf}\), (a): The parameter \(z_{yaf}\) represents the depreciation period of a transmission \(f\) transferring commodities through an arc \(a\) built in support timeframe \(y\). The depreciation period gives the economic and technical lifetime of a transmission investment. It thus features in the calculation of the invest cost factor and determines the end of operation of the transmission. The unit of this parameter is “a”, where “a” represents a year of 8760 hours. The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Transmission” sheet. Here each row represents another transmission \(f\) transferring commodities through an arc \(a\) and the column with the header label “depreciation” represents the parameters \(z_{yaf}\) of the corresponding transmission \(f\) and arc \(a\) combinations.

Transmission Capacity Investment Costs, \(k_{yaf}^\text{inv}\), m.transmission_dict['inv-cost'][t]: The parameter \(k_{yaf}^\text{inv}\) represents the book value of the investment cost for adding one unit new transmission capacity to a transmission \(f\) transferring commodities through an arc \(a\) in support timeframe \(y\). To get the full impact of the investment within the modeling horizon this parameter is multiplied with the factor \(I_y\) for the investment made in modeled year \(y\). The unit of this parameter is €/MW. The related section for the transmission capacity investment cost in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Transmission” sheet. Here each row represents another transmission \(f\) transferring commodities through an arc \(a\) and the column with the header label “inv-cost” represents the transmission capacity investment cost of the corresponding transmission \(f\) and arc \(a\) combinations.

Annual Transmission Capacity Fixed Costs, \(k_{yaf}^\text{fix}\), m.transmission_dict['fix-cost'][t]: The parameter \(k_{yaf}^\text{fix}\) represents the annual fix cost per one unit capacity of a transmission \(f\) transferring commodities through an arc \(a\). The unit of this parameter is €/(MW a). The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Transmission” sheet. Here each row represents another transmission \(f\) transferring commodities through an arc \(a\) and the column with the header label “fix-cost” represents the parameters \(k_{yaf}^\text{fix}\) of the corresponding transmission \(f\) and arc \(a\) combinations.

Transmission Usage Variable Costs, \(k_{yaf}^\text{var}\), m.transmission_dict['var-cost'][t]: The parameter \(k_{yaf}^\text{var}\) represents the variable cost per unit energy, that is transferred with a transmission \(f\) through an arc \(a\). The unit of this parameter is €/MWh. The related section for this parameter in the spreadsheet corresponding to support timeframe \(y\) can be found under the “Transmission” sheet. Here each row represents another transmission \(f\) transferring commodities through an arc \(a\) and the column with the header label “var-cost” represents the parameters \(k_{yaf}^\text{var}\) of the corresponding transmission \(f\) and arc \(a\) combinations.