Operational expenditure modelling
Calculate a comprehensive operating model, driven by service agreements, vessel and logistics strategy, site-specific weather and projected failure rates.
What OPEX does
Calculate annual costs directly from operational activities. Across seven chapters and thirty-two sections — from service agreements to decommissioning — every cost is transparent, accessible, and interlinked.
Costs are organised by agreement type, reflecting real-world financial commitments. Whether for gearbox exchanges, transmission services, or asset management, the model accounts for specific scopes, caps, and allocations, assigning precise costs to every logistical choice.
Incorporates site-specific offshore data: vessel rates, port distances, technician shifts, and component failure rates. Automatically captures site-specific wind/wave persistence data to replace broad assumptions with rigorous analysis.
For licensed users, OPEX cases can be instantly validated against NREL's open-source WOMBAT simulation to provide an independent check on your project outcomes.
Live · Demonstration project
£952m
Operating cost over 25 years
Every year costed separately — the step down is the service agreements ending
What you get with OPEX
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Complete contract modelling
Seven agreement types, each with its own scope, fixed and variable fees, caps and exclusions. The main component exchange split records who carries the cost, what the cap is, and who supplies vessel and crane for each exchange type.
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Weather-constrained logistics
Vessel spreads during and after the availability agreement, ports and nursery areas with their transit distances, and helicopter operations — run against site-specific wave and wind persistence for complete model accuracy.
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Technicians costed
A full technician model; headcount, shifts, travel, mobilisation and vessel hours. Calculate team cost for installation, maintenance and inspection.
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Failures and component exchange
Turbine components, cables, foundations and transmission failure rates with repair durations, spares and the vessel class each exchange demands, so the exchange programme and its cost are derived from known reliability profiles.
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Output by year, in any currency
Annual operating cost split by category and by year, with revenue and availability alongside, exportable to Excel and PowerPoint. Currency is dynamically converted, as needed.
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WOMBAT comparison [Optional]
Run the same scenario through NREL's WOMBAT simulation and compare each result with a clear explanation of the alignment or differences between models.
OPEX in use
Drawn in the product's own interface, and every figure is real: they come from our live Demonstration project — a 288.75 MW floating wind farm in the central North Sea — and its Default Scenario, so anything shown here can be reproduced in front of you. No client or commercial data appears on this page.
One model, and it knows what CAPEX already decided
The Project chapter of the OPEX scenario. Nine of these values are not OPEX's to set — turbine, foundation, capacity, operating life come from the capital model and are shown locked, with a link back to the source. That is the difference between one model and five spreadsheets that agree on a good day.
Project
Project info
The grey wells are the mirrored ones. Change the turbine in CAPEX and they follow; try to change them here and the form sends you to the record that owns them. Seven chapters and thirty-two sections sit behind the bar at the top, and the chips under the chapter title are its sections.
Weather windows become waiting time
A cut of this project's own wave persistence matrix, generated from 20 years of CMEMS GLOBAL_MULTIYEAR_WAV_001_032 three-hourly data at the grid point 8.84 km from the site centroid. The model reads the whole grid; the page shows one readable slice.
Wave persistence — P50, Hs ≤ 1.5 m
| Window | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Year |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 6 hours | 10.9 | 14.5 | 18.9 | 44.0 | 54.2 | 63.7 | 71.6 | 63.3 | 45.2 | 17.9 | 14.4 | 11.9 | 35.9 |
| 12 hours | 8.3 | 11.4 | 14.7 | 40.8 | 49.0 | 59.0 | 66.1 | 58.9 | 40.6 | 12.5 | 10.6 | 9.3 | 31.8 |
| 24 hours | 4.6 | 7.7 | 10.5 | 32.9 | 40.7 | 50.6 | 56.2 | 49.4 | 29.4 | 7.1 | 5.4 | 6.7 | 25.1 |
| 48 hours | 0.0 | 3.7 | 4.4 | 20.2 | 30.0 | 39.8 | 45.0 | 35.3 | 15.4 | 1.8 | 0.6 | 1.4 | 16.5 |
| Mean wait for a 12-hour window | 188 | 125 | 101 | 46 | 26 | 14 | 10 | 19 | 50 | 109 | 187 | 217 | 91 |
Where the year's downtime went
2026 — the second operating year| Cause | Downtime, hours | Lost production, MWh | Share of loss |
|---|---|---|---|
| Waiting on vessel | 7,148.1 | 57,543 | 69.3% |
| Reactive maintenance — medium weather limits | 998.5 | 8,038 | 9.7% |
| Reactive maintenance — high weather limits | 870.3 | 7,006 | 8.4% |
| Reactive maintenance — low weather limits | 525.1 | 4,227 | 5.1% |
| Main component exchange | 350.1 | 2,818 | 3.4% |
| Annual servicing | 650 | 2,785 | 3.4% |
| Inspections | 138 | 591 | 0.7% |
| Total | 10,680.1 | 83,008 | 100.0% |
The weather record is a data source with provenance, not an assumption: cmems_mod_glo_wav_my_0.2deg_PT3H-i, grid point 57.8 N 1.6 E, 58,440 samples at 3-hour spacing, none missing. Generated using E.U. Copernicus Marine Service Information; https://doi.org/10.48670/moi-00022
Operating cost over the life of the asset
The OPEX results page. Annual cost by category across construction, twenty-five operating years and a three-year decommissioning campaign — then the whole-life split, and what one contractual decision is worth.
OPEX Results
View a single scenario or compare up to 3 scenarios side-by-side.
Select scenarios
1 / 3Default Scenario OPEX Breakdown Analysis
Whole-life opex
£951.54m
Average per year
£32.81m
Per MWh
£26.73
Wind farm availability
92.45%
Annual operating cost, £m
| Category | £m | Share | Share of whole-life cost |
|---|---|---|---|
| Contracts and agreements | 315.05 | 33.11% | |
| Other operating costs | 268.55 | 28.22% | |
| Vessels and logistics | 154.17 | 16.20% | |
| Contingency | 86.35 | 9.08% | |
| Turbine non-contractual | 30.50 | 3.21% | |
| Foundations | 28.86 | 3.03% | |
| Decommissioning | 25.00 | 2.63% | |
| Inter-array cables | 23.35 | 2.45% | |
| O&M base | 10.03 | 1.05% | |
| Export cable | 7.40 | 0.78% | |
| Pre-COD | 1.65 | 0.17% | |
| Offshore substation | 0.62 | 0.07% |
What the exchange strategy is worth
Default Scenario against "Wombat comparison"| Measure | Tow-to-shore | In situ | Movement |
|---|---|---|---|
| Whole-life operating cost, £m | 951.54 | 901.13 | −50.41 |
| Wind farm availability, % | 92.45 | 93.41 | +0.96 pp |
| Operating cost, £ per MWh Discounted cost over discounted yield | 27.24 | 26.37 | −0.87 |
Two scenarios differing in one decision — whether a main component exchange is done in situ or by towing the unit to shore. That is the whole edit, and it is worth £50.41m and 0.96 points of availability over the life of the asset.
See it on your own project
Book a demo and we will walk through the module with your numbers, not ours.
More of the toolkit
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Pre-FID
Take the engineering case to an investment case: cash flow, LCoE, NPV and IRR built on the CAPEX, OPEX and AEP you already modelled.
M&A
Value an operating or consented asset properly: transaction structure, debt, tax, allowances and sensitivities in one model.