Small wind / Buyer questions
Energy and economics
When would measurements at more than one point on a property be useful for small-wind planning?
The short answer
Measurements at more than one position can be useful when plausible turbine sites have materially different exposure and the difference could change the project decision. The purpose is to test a spatial question. It is not to collect several short records and automatically regard their average as the resource for the whole property.
Define the spatial question first
Map the candidate positions, relevant obstacles and important wind directions. State what needs resolving: shelter behind a tree line, exposure across a broad field or a change in terrain. Record the proposed turbine location separately from temporary sensor positions.
A useful campaign compares a limited set of meaningful alternatives. Adding instruments without a question can consume the budget while leaving the final location unsupported.
Keep comparisons contemporaneous
Two locations measured in different weeks may appear different because the weather changed. Concurrent measurements, comparable instrument setups and common processing rules make the spatial comparison more informative. Where a reference instrument is used, document how it links the observation periods.
Match the height basis where practical and preserve installation photographs and coordinates. A sheltered sensor at one position and a taller exposed sensor at another do not isolate location alone. The assessor should identify the remaining height and instrumentation effects.
Use the result to narrow the next stage
Compare the direction-dependent differences and their consistency rather than selecting the largest isolated reading. Ask whether the observed advantage persists in the sectors likely to contribute useful generation. A short spatial exercise may support candidate selection while still being insufficient for annual energy prediction.
The deliverable should name the preferred assessment location, rejected alternatives, evidence period and unresolved uncertainty. The next step may be a longer campaign at one position, a layout change or stopping the project if no feasible location offers credible exposure.
Sources
- U.S. DOE Small Wind Guidebook: resource and siting background
- U.S. DOE wind-resource maps: model resolution and site limitations
Examples are illustrative. Confirm product-specific performance, compatibility and supply scope in the applicable documents.