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Power Transformation Station

Screening-stage parametric estimate of substation CAPEX split, annual O&M, total annual cost, and levelized cost per MWh of energy throughput.

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alexi

I do low-carbon energy stuff for 10 years & build things I wish existed.

Inputs

Rated active power capacity to be transformed/handled by the station (screening value).

min 1 · max 2000 · step 1 · MW

Select the representative HV class; used as a cost multiplier.

Classical station options with different cost structures and multipliers.

Results

Annual O&M cost

Fixed O&M estimated as a fraction of CAPEX

…EUR/year

Total CAPEX

Total installed capital cost of the station (screening estimate)

…EUR

Annual energy throughput

Expected annual energy delivered by the station

…MWh/year

Specific CAPEX (scaled & clamped)

Parametric estimate at the selected voltage class and station type

…EUR/kW

CAPEX split: Transformers

Transformers portion of total CAPEX

…EUR

CAPEX split: Switchgear

Switchgear (AIS/GIS) portion of total CAPEX

…EUR

CAPEX split: Civil & buildings

Civil works, buildings, foundations, site works

…EUR

Levelized cost

Expected average utilization of the station as a percent of rated power (0–100%).

%

min 0 · max 100 · step 0.1 · %

Economic lifetime of the station (years) for annualization.

years

min 1 · max 80 · step 1 · years

Input not found: discount_rate

Levelized cost of throughput

Levelized cost per MWh of energy throughput

…EUR/MWh

About

Calculator context

Introduction

This calculator provides a screening-stage cost estimate for an electrical power transformation station (substation) as a function of rated power, utilization, voltage class, and station configuration (AIS/GIS; indoor/outdoor). It is intended for early project development to rapidly compare options and produce a transparent CAPEX split and levelized cost per MWh of throughput.

The approach follows common energy-cost methodology patterns used in industry and public techno-economic sources (e.g., IRENA/IEA costing conventions for annualization and levelized metrics) and aligns with typical substation cost decomposition used in NREL/DOE-style parametric infrastructure estimates (while recognizing that actual EPC pricing is highly site- and utility-specific).

Methodology

The model uses a reference specific CAPEX adjusted by discrete option multipliers (voltage, technology) and an economy-of-scale exponent. Key equations:

  • Energy throughput: E_annual = P_rated * CF * 8760
    • P_rated in MW, CF in fraction (CF = capacity_factor_%/100), E_annual in MWh/year.
  • Specific CAPEX scaling: C_spec = clamp(C_ref * M_voltage * M_type * (P/Pref)^k, C_min, C_max)
    • C_ref in currency/kW at Pref (MW); k is a scaling exponent (economies of scale).
  • Total CAPEX: CAPEX_total = C_spec * P_kW
  • O&M scaling: f_om = clamp(f_om_ref * M_om_type * (P/Pref)^k_om, f_min, f_max)
    • O&M cost: OPEX_om = CAPEX_total * f_om.
  • Capital recovery factor (CRF) (standard annuity method): CRF = (r*(1+r)^n)/((1+r)^n-1)
    • r = discount_rate, n = lifetime_years.
  • Annualized CAPEX: CAPEX_ann = CAPEX_total * CRF
  • Total annual cost: Cost_ann = CAPEX_ann + OPEX_om
  • Levelized cost of throughput: LC = Cost_ann / E_annual (currency/MWh)

CAPEX split is computed as fixed fractions (by station type) for transformers, switchgear, civil/buildings, protection & control, installation/commissioning, engineering/owner’s costs, with contingency as the remaining share.

Applications

  • Business developer: compare indoor GIS vs outdoor AIS at a given voltage class to understand first-order cost uplift and annualized impact.
  • Grid connection team: estimate substation budget and how cost/MWh changes with expected utilization (capacity factor) for renewable interconnection.
  • Early EPC/owner estimate: generate a transparent CAPEX breakdown to seed a cost plan before vendor quotes and site-specific studies.

Model

91 variables — inputs, calculations and outputs, with their dependencies.

91 variables shown of 91
VariableValueUnitDepends on
400MW—
2——
1——
90%—
7%—
40years—
VariableFormulaUnitDepends on
if(((<=)+(<)+(>3)+(<)+(>4)+(<)+(>)+(<)+(>)+(<)),,)bool
/—
*kW
if(==1,,if(==2,,if(==3,,)))—
if(==1,,if(==2,,))—
**EUR/kW
(max(,)/max(,))^—
*EUR/kW
if(==1,,if(==2,,))—
*—
(max(,)/max(,))^—
*—
clamp(,,)—
(*(1+)^)/max(((1+)^-1),)—
/—
if(==1,,if(==2,,))—
if(==1,,if(==2,,))—
if(==1,,if(==2,,))—
if(==1,,if(==2,,))—
if(==1,,if(==2,,))—
if(==1,,if(==2,,))—
max(+,)—
max(+,)—
max(+,)—
max(+,)—
max(+,)—
max(+,)—
max(-(+++++),)—
*EUR
*EUR
*EUR
*EUR
VariableFormulaUnitDepends on
clamp(,,)EUR/kW
*EUR
*EUR/year
*EUR/year
+EUR/year
**MWh/year
/max(,)EUR/MWh
*EUR
*EUR
*EUR

Assumptions

43 assumptions used in the calculations

  • Prevents division-by-zero and undefined operations in scaling and levelized-cost calculations.

    0.000001
    Model numerical safeguard

  • Explicit zero constant to avoid inline numeric literals.

    Market range 0

    0
    Model constant

  • Explicit unity constant to avoid inline numeric literals (e.g., for shares summing to 1).

    Market range 1

    1
    Model constant

  • Explicit 100 constant for percent-to-fraction conversion.

    Market range 100

    100
    Model constant

  • Converts MW to kW for specific CAPEX multiplication.

    Market range 1000

    1000kW/MW
    Unit conversion

  • Reference size for the parametric cost curve; represents a mid-size grid connection station.

    100MW
    Model reference point

  • Represents an order-of-magnitude installed cost for an outdoor AIS station at HV class and reference size before multipliers and scaling.

    70EUR/kW
    Generic screening CAPEX anchor

  • Lower voltage classes generally require less insulation/clearance and lighter switchgear, reducing CAPEX.

    0.6
    Model assumption

  • Baseline multiplier for HV class.

    1
    Model assumption

  • EHV stations typically require higher insulation levels, larger clearances, and higher-rated equipment.

    1.5
    Model assumption

  • Very high voltage stations have materially higher equipment and civil requirements.

    2.2
    Model assumption

  • Baseline station type (outdoor AIS).

    1
    Model assumption

  • Indoor AIS typically adds building/civil scope and may increase installation complexity.

    1.2
    Model assumption

  • GIS equipment typically carries higher unit costs but may reduce footprint; overall tends to be higher CAPEX.

    1.8
    Model assumption

  • Captures economies of scale: larger stations often have lower specific CAPEX.

    Market range -0.05 to -0.30

    -0.15
    Parametric scaling assumption

  • Prevents unrealistic low outputs from scaling at very large sizes.

    20EUR/kW
    Model guardrail

  • Prevents unrealistic high outputs from scaling at very small sizes or extreme multipliers.

    400EUR/kW
    Model guardrail

  • Represents fixed annual O&M (inspection, maintenance, spares) as a fraction of CAPEX.

    0.02ratio
    Generic screening O&M fraction

  • Baseline O&M multiplier for outdoor AIS.

    1
    Model assumption

  • Indoor stations may require additional HVAC/building upkeep and access constraints.

    1.1
    Model assumption

  • GIS and indoor configurations can add maintenance specialization and building systems.

    1.2
    Model assumption

  • Captures mild economies of scale for fixed O&M with increasing station size.

    Market range -0.02 to -0.10

    -0.05
    Parametric scaling assumption

  • Prevents unrealistically low fixed O&M fractions under scaling.

    0.01ratio
    Model guardrail

  • Prevents unrealistically high fixed O&M fractions under scaling.

    0.04ratio
    Model guardrail

  • Transformer(s) are typically the largest equipment cost item in many stations.

    0.34ratio
    Heuristic split baseline (outdoor AIS)

  • Switchgear and bays are a major cost block; higher for GIS.

    0.24ratio
    Heuristic split baseline (outdoor AIS)

  • Civil/site works include foundations, cable trenches, roads, drainage, fencing.

    0.15ratio
    Heuristic split baseline (outdoor AIS)

  • Protection, control, SCADA, communications, metering.

    0.08ratio
    Heuristic split baseline (outdoor AIS)

  • Installation, testing, commissioning, temporary works.

    0.1ratio
    Heuristic split baseline (outdoor AIS)

  • Engineering, project management, permitting, owner’s costs (screening).

    0.05ratio
    Heuristic split baseline (outdoor AIS)

  • Indoor AIS tends to shift budget toward buildings/civil and away from transformers as a share.

    -0.01ratio
    Heuristic split adjustment

  • Indoor layouts may modestly increase switchgear share (enclosures, buswork).

    0.01ratio
    Heuristic split adjustment

  • Indoor configuration typically adds building and related civil works.

    0.02ratio
    Heuristic split adjustment

  • No systematic change assumed at screening stage.

    0ratio
    Heuristic split adjustment

  • No systematic change assumed at screening stage.

    0ratio
    Heuristic split adjustment

  • Engineering/owner’s share assumed unchanged at screening stage.

    0ratio
    Heuristic split adjustment

  • GIS tends to increase switchgear share; transformers become a smaller share of total.

    -0.03ratio
    Heuristic split adjustment

  • GIS equipment commonly increases switchgear share due to higher unit costs.

    0.08ratio
    Heuristic split adjustment

  • Indoor GIS typically requires buildings and auxiliary systems; increases civil/buildings share.

    0.04ratio
    Heuristic split adjustment

  • Slight increase allowed for additional monitoring/interlocks typical in GIS implementations.

    0.01ratio
    Heuristic split adjustment

  • GIS can reduce some on-site assembly/installation scope (more factory-assembled), reducing installation share.

    -0.06ratio
    Heuristic split adjustment

  • Engineering/owner’s share assumed unchanged at screening stage.

    0ratio
    Heuristic split adjustment

  • Standard hours per year for energy throughput calculation.

    Market range 8760

    8760h/year
    Standard calendar