Solutions / Engineering guide
One Wind Turbine vs Multiple Small Turbines
Equal total rated power does not establish equal energy, installation scope or service needs. Compare a single turbine and several smaller units as complete project candidates, with identified positions, equipment configurations and assumptions for each.
Compare the layout and equipment behind the total kW.
Multiple turbines add resource and integration questions as well as equipment capacity. Use the same load and delivery boundary for both candidates before deciding which deserves further design.
01 / Candidate definition
Specify the individual machines in each option.
List turbine model, quantity, rated power, rotor diameter and proposed position for every unit.
List turbine model, quantity, rated power, rotor diameter and proposed position for every unit. State whether the comparison concerns equipment supply, installed generation or useful supply to a particular load. Keep tower and electrical-package scope alongside the turbine list.
The current MARSTON range comprises 5, 10, 20, 30 and 50 kW electric-yaw models. A project can discuss candidate combinations, but a summed kW value does not approve the layout or a common electrical connection. Identify the proposed devices before comparing the alternatives.
02 / Rotor geometry
Show what equal rated power does and does not describe.
Confirmed geometry example: one FD7.5-10KW has a 7.5 m rotor; two FD5-5KW turbines each have a 5 m rotor.
Confirmed geometry example: one FD7.5-10KW has a 7.5 m rotor; two FD5-5KW turbines each have a 5 m rotor. Both candidates total 10 kW rated capacity. Using circular disk area A = π × D² / 4 gives approximately 44.2 m² for the single rotor and 39.3 m² for the two disks together.
This calculation uses the confirmed diameters and compares geometry only. It is not an electrical-yield estimate, occupied ground area or spacing recommendation. Different power curves, control conditions, positions and equipment still need their own evidence before either candidate’s useful output can be assessed.
03 / Resource interaction
Assess the wind at each position and relevant directions.
Record candidate coordinates, hub heights, obstacles and directional wind information.
Record candidate coordinates, hub heights, obstacles and directional wind information. Several turbines share a site but need not experience identical incoming wind. Ask the assessor to review whether another unit’s position affects the relevant flow and how that is handled in the calculation.
SAM’s wind-farm documentation treats layout and wake effects as assessment inputs. Its example model does not establish a validated layout for MARSTON small turbines. Do not multiply a single-unit energy estimate by quantity without preserving position differences and the applicable interaction assumptions.
04 / Electrical package
Review the connection of each unit to the project.
Identify the controller and conversion equipment proposed for each turbine and the intended common delivery point.
Identify the controller and conversion equipment proposed for each turbine and the intended common delivery point. Ask the designer to define which connections, controls, meters and other devices are individual or shared. Equal aggregate kW does not prove that generator outputs can be combined directly.
Keep source identities and permitted operating cases with the interface schedule. Include the available connection scope and any restrictions. A multi-unit arrangement needs its own equipment review; no parallel-operation or shared-converter compatibility is assumed.
05 / Service comparison
Include repeated work and common dependencies.
Compare tower and foundation quantities, delivery access, cable routes, monitoring records and service responsibilities.
Compare tower and foundation quantities, delivery access, cable routes, monitoring records and service responsibilities. Identify whether a spare or service task is specific to one model or can only be considered common after applicability review. Do not invent a common parts list.
Several units can have separate service events while retaining dependencies on shared equipment. One unit being unavailable does not prove that the others will continue supplying the required load. Record the actual operating arrangement and failure assumptions instead of assigning an automatic reliability benefit to quantity.
06 / Project decision
Use evidence and costs at the same boundary.
Compare the candidates using aligned resource and demand inputs, applicable per-unit curves, identified layout assumptions and the same useful-power boundary.
Compare the candidates using aligned resource and demand inputs, applicable per-unit curves, identified layout assumptions and the same useful-power boundary. Keep local works and repeated equipment in the scope record. The cost guide helps avoid comparing a bare turbine with an installed array.
Send MARSTON the candidate unit lists, positions, intended connection and unresolved questions for a wind-equipment review. State which option is advanced and why, and what evidence could change the decision. No array gain, universal separation distance or guaranteed redundancy is promised by this guide.
Continue the review with Wind Turbine Rotor Clearance & Three-Dimensional Layout.
Continue the review with Load Profiles for Small Wind Power: kW, kWh & Timing.
Continue the review with Wind Turbine Transport, Delivery & Pre-Installation Storage.
For the flow interactions considered in a multi-turbine layout, review the guide to wake deficit, mixing and recovery.
General background: NLR SAM: layout and wake-assessment scope. 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 |
|---|---|---|
| Unit schedule | Models, quantities, diameters, heights and positions | Define both project candidates. |
| Comparison boundary | Load, output location and equipment scope | Compare the same service. |
| Resource assumptions | Per-position data, directions and interaction assessment | Avoid multiplying unsupported estimates. |
| Electrical package | Individual and shared devices, interfaces and restrictions | Review the actual connection. |
| Service & cost scope | Repeated tasks, common dependencies and local works | Keep the decision complete. |
Engineering questions.
Does equal total kW mean equal annual energy?
No. The applicable curves, resources, positions, configuration and project restrictions determine the comparison.
What does the 44.2 versus 39.3 m² example prove?
It compares rotor disk geometry from confirmed diameters. It establishes neither electrical output nor the installation footprint.
Can one unit’s annual estimate be multiplied by quantity?
Review each position and interaction assumptions before aggregating the applicable unit estimates.
Is there a universal spacing rule for this range?
No spacing is approved here. The actual layout, directions and design information need assessment.
Can several turbines share any converter?
The proposed electrical arrangement and devices require configuration-specific compatibility review.
Do multiple units guarantee uninterrupted supply?
Continuity depends on the required load, operating arrangement, shared dependencies and backup. Quantity alone does not guarantee it.
Technical enquiry
Bring your project information to the discussion.
Equal total rated power does not establish equal energy, installation scope or service needs. Share the available information and the equipment scope you want reviewed in a technical quotation.