Does wind above cut-in speed mean a turbine will supply useful site power?

The short answer

Wind above a stated cut-in speed does not automatically mean the system supplies a useful amount of power to the site. Cut-in identifies a defined operating threshold; the actual output above it follows the applicable performance and control behaviour. Net delivered energy also depends on losses, auxiliaries and operating conditions.

Ask what the threshold describes

Request the definition behind the advertised value and the configuration to which it applies. Rotor movement, controller activation, electrical generation and export to a site connection are different events. A low threshold for one event should not be presented as evidence of meaningful output at another boundary.

Keep the product-specific threshold in the relevant documentation rather than inferring it from a generic description of small-wind operation.

Read the curve in the relevant speed range

Examine output across the site's common wind conditions instead of counting every above-threshold hour as rated production. A distribution concentrated near low output can yield modest annual energy even if the turbine frequently starts generating.

For an illustrative screening comparison, calculate generation from the actual curve and represented hours. Do not multiply the number of above-cut-in hours by nameplate power. That shortcut discards the curve behaviour the threshold does not describe.

Compare net energy with the intended service

Identify the measurement boundary and any system consumption or conversion losses included in the estimate. Then compare useful output with demand timing. A small positive gross output is not necessarily enough to run a particular load or provide reliable off-grid service.

The equipment enquiry should include the resource distribution and the required service, while requesting the supported curve and threshold definitions. This keeps a low cut-in claim in perspective without assuming that any specific MARSTON model has an unverified startup performance or net-output characteristic.