Is maximum inverter efficiency enough to compare wind systems?

The short answer

No. A maximum efficiency figure is a point or limited region of operation, not an annual-energy result. A wind converter can spend substantial time at other input powers or in standby. Compare its efficiency over the relevant operating range, any idle consumption and the conditions behind the published measurements. Use the same energy boundary for every proposal so that one supplier's generator energy is not compared with another's net delivered energy.

Weight efficiency by energy, not by the largest percentage

Hypothetical two-bin illustration: suppose 100 kWh enters a converter in a low-power region at 90% efficiency and another 100 kWh enters at 97%. The output is 90 + 97 = 187 kWh, giving 93.5% across those two bins before separately counted standby use.

Neither efficiency is a MARSTON specification. The calculation shows why the operating distribution matters and why a published maximum of 97% would not describe this whole period.

Keep the comparison boundaries consistent

Item	Comparison question
Conversion map	Which input powers, voltages and temperatures are represented?
Standby energy	Is it included in the reported result?
Other equipment	Are rectifier, cable and auxiliary losses inside or outside the boundary?

Do not subtract the same loss again if a quoted net-energy estimate already includes it.

Use realistic low-output periods

A project with long calm periods and intermittent low generation can be sensitive to fixed consumption. Another site with a different resource profile may give different weight to the same converter's operating regions.

Ask for the applicable performance evidence and the annual model's treatment of each loss. An unsupported single efficiency claim should not become a guaranteed energy saving or a reason to assume compatibility.

Distinguish power from energy in efficiency claims

An instantaneous input/output measurement gives an operating-point result. Annual efficiency requires energy integrated over the period with consistent treatment of starts, stops and standby. A high-power demonstration can be valid evidence for that one condition while contributing little information about the low-output periods that dominate a different project operating profile.