Solutions / Engineering guide
Wind Turbine Technical Bids: Compare the Same Supply Scope
A quoted turbine rating does not describe everything included in a wind power offer. Once bids arrive, compare the same equipment boundary and project duties before comparing headline amounts. Keep an omitted item distinct from an included item whose suitability has not yet been demonstrated.
Normalise the offer before judging the difference.
A useful bid comparison reveals scope gaps and evidence gaps separately, with each adjustment tied to the supplier’s actual response.
01 / Comparison boundary
Define the service and equipment being compared.
Name the turbine assembly, controller, converter, tower, site works and intended output interface separately.
Name the turbine assembly, controller, converter, tower, site works and intended output interface separately. Record whether the comparison is equipment supply, an integrated package or a broader project proposal. Two bids with the same rated kW can still cover different equipment and responsibilities.
Keep the original bid untouched and build a separate comparison record. The DOE Small Wind Guidebook encourages reviewing manufacturers’ information. Identify what each offer delivers against the same project boundary before comparing headline amounts.
02 / Scope differences
Mark omissions without silently filling them.
For each scope row, use states such as included, explicitly excluded, optional, buyer-supplied or unclear.
For each scope row, use states such as included, explicitly excluded, optional, buyer-supplied or unclear. Attach the relevant quotation line and revision. An optional converter should not be treated as included simply because a matching photograph appears in a brochure.
An original comparison row might read “site output converter: optional; interface evidence pending; external cost not obtained”. That records three separate issues. Do not enter a guessed external price or transform “pending” into a technical pass just to complete the spreadsheet.
03 / Technical evidence
Compare evidence applicable to the offered version.
Match model identity, documented mechanical and electrical characteristics, and the proposed controller/converter combination.
Match model identity, documented mechanical and electrical characteristics, and the proposed controller/converter combination. A family-level description is weaker evidence for a specific option than an applicable configuration document. Record the operating and measurement conditions beside any claimed result.
MARSTON’s current turbine range has ratings of 5, 10, 20, 30 and 50 kW. Those labels alone do not establish equivalent annual energy, certification, output voltage or third-party compatibility. Use the report-scope guide when evidence differs between bids.
04 / External work
Expose costs and duties outside the supplier’s boundary.
Identify the party responsible for foundations, local approvals, electrical design, installation and commissioning where these are outside an equipment offer.
Identify the party responsible for foundations, local approvals, electrical design, installation and commissioning where these are outside an equipment offer. A technically complete equipment list can still leave an important integration task unassigned. Separate missing duties from missing materials.
Use the same treatment for transport endpoints, training and service access. Ask whether a required task is excluded, offered separately or awaiting a named local provider. Keep availability of that provider as an open project dependency rather than an assumed supplier service.
05 / Clarifications
Keep a decision trail for material differences.
Give each clarification an identifier, question, affected scope row, responding party and response date.
Give each clarification an identifier, question, affected scope row, responding party and response date. Record whether the answer changes the equipment, price basis, responsibility or evidence status. A response about delivery timing should not close an unrelated interface question.
Freeze the comparison against named bid revisions after clarification. If an offer changes, reassess the affected rows instead of overwriting the previous conclusion. This preserves why one proposal was judged more complete while allowing remaining uncertainties to stay visible.
06 / Decision record
Explain the selection against explicit criteria.
Summarise material inclusions, exclusions, unresolved interfaces and externally assigned tasks.
Summarise material inclusions, exclusions, unresolved interfaces and externally assigned tasks. Apply the buyer’s stated criteria consistently; do not manufacture a supplier ranking from incomplete evidence. A lower amount can reflect a narrower scope rather than a more economical complete project.
For a MARSTON enquiry, identify the required assembly and separate electrical equipment, the output boundary and missing bid information. Turbines, controllers and converters can be discussed separately. The comparison does not establish a turnkey offer, approved site installation or guaranteed project performance.
Continue the review with Wind Turbine Supply vs Turnkey: Project Responsibilities.
Continue the review with Wind Turbine Technical Tenders: Requirement Response Matrix.
Continue the review with Wind Turbine Warranty Scope: Questions for the Actual Offer.
General background: DOE Small Wind Guidebook: equipment comparison and supplier questions. These references explain industry concepts; they are separate from the applicable MARSTON product and project documents.
Prepare the information for this review.
Use the checklist to organise the project information. Mark unavailable items and retain document references.
| Review item | Information to provide | Purpose |
|---|---|---|
| Bid identity | Supplier, quotation date, revision and named configuration | Keep responses traceable. |
| Scope states | Included, excluded, optional, external or unclear per item | Expose material differences. |
| Evidence match | Applicable version, result conditions and open questions | Avoid family-wide assumptions. |
| Outside duties | Named designer, installer and owner tasks | Reveal incomplete project scope. |
| Selection basis | Criteria, resolved differences and residual uncertainty | Explain the purchasing decision. |
Engineering questions.
Can the cheapest turbine quote be the cheapest complete project?
Possibly, but that conclusion requires the same equipment, external work and service boundary.
How should an unclear item be compared?
Keep it unclear and request a specific response rather than assume inclusion.
Does equal rated power mean equal energy?
No. Resource, applicable performance evidence and actual operating constraints also matter.
Should optional items be included automatically?
No. Identify the option selected and its price and configuration evidence.
Is a clarification email enough to change the comparison?
Retain the response and confirm which quotation revision or scope item it changes.
What should the final comparison show?
Material scope differences, evidence gaps, outside responsibilities and the stated decision criteria.
Technical enquiry
Bring your project information to the discussion.
A quoted turbine rating does not describe everything included in a wind power offer. Share the available information and the equipment scope you want reviewed in a technical quotation.