What Should You Check When Comparing Offshore Costs Across Countries?

Before comparing offshore installation costs across countries, establish whether the figures describe the same work under comparable delivery conditions. A lower quoted price may reflect a narrower scope, a shorter vessel commitment, different tax treatment or an assumption that a suitable port and crew are already available. Until those differences are accounted for, a country ranking can be misleading.

A useful comparison has two layers: a normalized estimate for the same defined scope, and a separate view of the local conditions that will affect execution. The first helps identify price differences; the second shows whether those prices are achievable for the project being planned.

Start with the work included in each estimate

“Installation cost” can cover anything from the offshore lifting operation alone to a package that includes engineering, port handling, transport, installation, testing and handover. A foundation installation estimate, for example, may include the main vessel but exclude pre-installation surveys, seabed preparation, secondary steel installation or final inspection. Another estimate may bundle some or all of those activities.

Before adjusting for geography, put both estimates against the same work breakdown. Identify who supplies the components, where the contractor takes custody, what happens offshore and what evidence is required before the work is accepted. For a cable package, the boundary between installation and other costs can shift depending on whether route preparation, burial, crossings, protection and testing are included.

The comparison should also state the quantities and units behind each figure. A cost per foundation, per kilometre of cable or per installed megawatt can be useful for screening, but each conceals different assumptions. Cost per megawatt, for instance, changes with turbine capacity and layout even when the installation method is similar. A figure expressed per day cannot be compared with a completed-work price without an estimate of the number of days and an understanding of what happens if operations take longer.

Use the same project stage when possible. An early feasibility allowance and a tendered price do not carry the same evidential weight: the latter may be based on a more developed design and clearer contractual conditions, but it can still contain exclusions and qualifications. An awarded contract value is not automatically the final installed cost, and an announced project budget does not establish what was spent.

Put the figures on the same commercial basis

Currency conversion is necessary, but it is only one part of normalization. Record the original currency, the price date and the exchange rate used for the comparison. Where costs will be incurred over several years, distinguish between an estimate converted at one reference rate and a cash-flow model that applies exchange-rate assumptions to payments as they fall due. The latter may be more relevant to investment decisions, although its result depends on assumptions that can change.

Check whether the figures are nominal or expressed in constant prices, and whether escalation is included through the planned installation period. Converting a historic price into another currency without addressing its price date can make an older estimate appear artificially attractive. Equally, adding a generic escalation allowance to every line may obscure the fact that vessel, labour and equipment costs do not necessarily move together.

Taxes and duties require a project-specific treatment. Separate recoverable taxes from costs that remain with the project, and identify any duties, withholding obligations or other charges included in one estimate but excluded from another. Recovery can depend on the contracting structure and applicable local rules; a gross invoice amount is not always the economic cost to the owner. Financing costs should also be shown separately from installation expenditure unless both estimates use the same financing boundary.

Contract terms can be as influential as the headline rate. A fixed price, a day-rate arrangement and a target-cost contract distribute delay risk differently. Ask whether standby, fuel, port fees, insurance, crew changes and demobilization are included, and who pays when work is interrupted. A lower day rate with uncapped standby exposure can produce a higher outturn cost than an offer with a higher rate and a more comprehensive risk allocation.

Test whether the offshore conditions support the price

Country is a convenient label, but offshore conditions vary within national waters. Water depth, distance from shore, seabed strength and metocean conditions can change the installation method and the equipment required. Comparing a sheltered, shallow-water project with a deeper or more exposed site may say more about site characteristics than about national cost competitiveness.

Start with the physical assumptions used to calculate productivity. For foundations, these may include soil conditions, installation tolerances and the number of units handled per trip. For cables, they can include route length, seabed conditions, burial requirements and the number of crossings. The same vessel rate will yield different unit costs if the expected pace of work changes.

Weather assumptions deserve particular scrutiny. An estimate may use a historical weather dataset, a planned season and operating limits for specific equipment to calculate workable periods. Another may apply a broad contingency without showing the underlying analysis. Compare the period and location represented by the data, the planned start date, the activity limits and whether transit, port operations and offshore work have different restrictions. A weather window suitable for lifting does not automatically mean that cable laying or transfer operations can proceed at the same time.

Do not treat an expected duration as a guaranteed duration. Ask for the basis of the duration estimate and, where available, a range or schedule-risk analysis. The commercial importance of delay depends on both the extra time and the contract: one party may bear vessel standby while another absorbs the cost of a missed handover or a later start for the next contractor.

Follow the vessel from its previous job to the next one

Mobilization can alter a comparison substantially. A vessel priced from a nearby port may need only a short transit, while the equivalent vessel for another project may need to travel from a different region, undergo preparation or wait for a suitable berth. Clarify the assumed starting location, mobilization date and destination after completion. Confirm whether transit, equipment changes, inspections and demobilization are priced or treated as client costs.

The installation port is part of that calculation. Quay load capacity, water depth, storage space, lifting arrangements and access to components can affect how many trips are needed and whether a vessel can be loaded as planned. A low port charge does not compensate for an unsuitable quay or a loading sequence that extends vessel time. Where an estimate assumes port upgrades or reserved space, show who pays for them and whether access is secured.

Separate local cost differences from local obligations

Labour comparisons need more than a wage rate. Establish the crew size, working pattern, travel and accommodation assumptions, required training and the division between vessel crew and specialist personnel. A lower local labour rate may be offset by additional travel, supervision or a different staffing arrangement; conversely, access to a qualified local workforce may reduce mobilization and crew-change costs.

Local requirements can also affect the feasible delivery model. Depending on the jurisdiction and project, vessel eligibility, immigration, employment rules, permits, customs procedures, environmental conditions or local-content commitments may influence the schedule and contracting structure. These obligations should be assessed against the actual route, vessel, personnel and scope of work. A requirement applicable to one activity or project location should not be assumed to apply identically to another.

Timing matters commercially. If a permit, customs clearance or specialist authorization is needed before work can start, the relevant comparison includes the assumed lead time and the consequences of a delay. An estimate that omits the cost of compliance is not necessarily cheaper; it may leave that cost with another party or outside the estimate altogether.

Build a comparison that exposes the decision

A practical comparison does not have to force every uncertainty into one number. For each country or project, retain the original estimate and create an adjusted view using a common scope, currency basis and price date. Show the adjustments separately so reviewers can see which differences came from the source estimate and which came from the analyst’s assumptions.

The following checks help turn a collection of quotes into a decision document:

• Scope: Are engineering, surveys, transport, offshore work, testing and handover included on the same basis?
• Commercial terms: Are vessel time, standby, fuel, insurance, taxes and demobilization allocated to the same party?
• Execution assumptions: Do the estimates use comparable quantities, installation methods, productivity, weather periods and port arrangements?
• Evidence: Is each figure a preliminary allowance, a bid, an awarded value or a recorded final cost, and what exclusions remain?
• Uncertainty: Which assumptions have the greatest effect on total cost, and who carries the consequences if they change?

Where a like-for-like adjustment is not possible, keep the difference visible rather than applying a precise-looking correction with no defensible basis. A missing seabed investigation, for example, may prevent a reliable adjustment to installation productivity. The appropriate result may be a range or a conditional comparison, with the site data identified as the next decision input.

It is also useful to distinguish the cost of a hypothetical common project from the cost of the actual opportunity in each country. The first can reveal differences in rates and commercial conditions. The second must preserve real differences in distance, seabed, port access and local obligations. Removing those differences may help explain the numbers, but it should not remove them from the investment decision.

Finally, test the assumptions that could reverse the ranking. Extend the offshore duration, change the vessel mobilization point or apply a different exchange-rate assumption, then observe which estimate is most exposed. If the preferred country changes under plausible conditions, the next step is to obtain better evidence or contract protection around those conditions, not to treat the lowest initial figure as the answer.