neqsim-capex-opex-screening

name	neqsim-capex-opex-screening
calculation_basis	screening
version	0.1.0
description	Educational factored CAPEX/OPEX screening that turns a bare equipment cost into a total installed CAPEX (Lang/Hand-style installation factor + contingency), an annual OPEX, and a lifecycle total cost of ownership. USE WHEN: a task needs a public, screening-level CAPEX and OPEX magnitude before detailed NeqSim CostEstimationCalculator estimating or qualified cost-engineering review.
last_verified	2026-06-24
requires	{"python_packages":[],"java_packages":[],"env":[],"network":[]}

CAPEX/OPEX Screening

Use this skill for a quick, public screening of project cost. Given a bare equipment cost, it applies a public installation (Lang/Hand-style) factor and a contingency allowance to estimate a total installed CAPEX, then adds a simple OPEX (a fraction of CAPEX per year plus an annual energy cost) to produce a lifecycle total cost of ownership. It is intentionally simple and should guide users toward the validated NeqSim CostEstimationCalculator (Turton / Peters / Ulrich / Seider correlations with CEPCI escalation) and the NeqSim MCP runFieldEconomics workflow for real estimates.

When to Use

• When a user wants a first-pass CAPEX and OPEX magnitude for a concept.
• When an agent needs a cost feed for an asset-value / NPV screening chain.
• When examples must run without confidential cost data or licensed estimating tools.

Inputs

• bare_equipment_cost_musd: total bare (uninstalled) equipment cost in million USD.
• installation_factor: Lang/Hand-style multiplier from bare to installed cost (default 3.5).
• contingency_fraction: contingency added on top of installed cost (default 0.2).
• opex_fraction_of_capex_per_year: annual OPEX as a fraction of total CAPEX (default 0.04).
• annual_energy_use_mwh: optional annual energy use for the energy-cost term (default 0).
• energy_price_usd_per_mwh: optional energy price (default 0).
• project_life_years: number of years used for the lifecycle OPEX roll-up (default 20).

Outputs

• installed_capex_musd: bare cost * installation factor.
• total_capex_musd: installed CAPEX including contingency.
• annual_opex_musd: OPEX-fraction term per year.
• annual_energy_cost_musd: energy-cost term per year.
• total_annual_opex_musd: sum of the two OPEX terms.
• lifecycle_opex_musd: total annual OPEX times project life.
• total_cost_of_ownership_musd: total CAPEX plus lifecycle OPEX.
• capex_warning: ok, watch, or high (magnitude flag vs a configurable threshold).
• neqsim_available: whether the optional NeqSim package is importable.
• assumptions: public assumptions and required follow-up.

Engineering Method

The factored estimate uses the classic installation-factor approach: CAPEX_installed = C_equipment * f_install, then CAPEX_total = CAPEX_installed * (1 + contingency). Annual OPEX is opex_fraction * CAPEX_total + (energy_use_MWh * energy_price_USD/MWh). The lifecycle roll-up multiplies the total annual OPEX by the project life, and the total cost of ownership adds CAPEX and lifecycle OPEX. The verdict is a simple magnitude flag against a configurable CAPEX threshold.

This skill applies no CEPCI escalation, material or pressure factors, location factor, currency conversion, phasing, financing, depreciation, or abandonment cost. It is a transparent placeholder that must be replaced by a validated NeqSim cost estimate for any quantitative use.

Python Usage Pattern

from capex_opex_screening import CapexOpexModel

model = CapexOpexModel()
result = model.evaluate(
    bare_equipment_cost_musd=120.0,
    installation_factor=3.5,
    contingency_fraction=0.25,
    opex_fraction_of_capex_per_year=0.04,
    annual_energy_use_mwh=180000.0,
    energy_price_usd_per_mwh=60.0,
    project_life_years=20,
)

print(result.total_capex_musd)
print(result.total_annual_opex_musd)
print(result.total_cost_of_ownership_musd)
print(result.capex_warning)

Validated NeqSim Path

This screening is a placeholder. For real cost estimates use:

• NeqSim CostEstimationCalculator — equipment-level CAPEX with Turton / Peters / Ulrich / Seider correlations, CEPCI escalation, material/pressure factors, and AACE class 1–5 (see the neqsim-equipment-cost-estimation skill).
• The field-development DCF utilities in neqsim.process.util.fielddevelopment for CAPEX/OPEX phasing and cash-flow modelling (see neqsim-field-economics).
• The NeqSim MCP runFieldEconomics tool for an orchestrated economics evaluation.

Escalation

Escalate any watch or high verdict, and any quantitative use, to a validated NeqSim cost estimate and qualified cost-engineering review.

Validation Checklist

• Inputs are validated and within stated ranges.
• Examples use public data only.
• Screening assumptions are stated explicitly.
• Limitations are respected.
• Quantitative use is escalated to validated NeqSim models.

Common Mistakes

Symptom	Cause	Fix
Unrealistic result	Inputs outside the screening range	Keep inputs within the stated bounds
Misused for design	Screening output taken as final	Escalate to validated NeqSim models

Limitations

• Educational screening only; not a validated design method.
• No confidential data or proprietary methods are included.
• Escalate any quantitative or design use to validated NeqSim workflows.

References

• NeqSim repository: https://github.com/equinor/neqsim
• NeqSim Skills Guide: https://github.com/equinor/neqsim/blob/master/docs/integration/skills_guide.md