Falling surcharge values exacerbate tense situation – night-time noise throttling as an underestimated economic risk

Many wind farms are only allowed to run at night with reduced power or even have to shut down individual turbines completely. What was originally defined as a precautionary measure in the approval phase can prove to be a massive economic disadvantage during ongoing operations – especially with today's tightly calculated bid values.

Especially at night, the wind blows stronger - at the same time, stricter sound guideline values apply. In many projects, cautious assumptions have been made in the permitting phase, which will persist throughout the life of the wind farm, although they would not be necessary on closer examination. Even small yield losses can cause project financing to falter.

"If a wind farm has to be permanently throttled at night, this can quickly become a project risk," says Fischer, Managing Director of Dezibel Engineering GmbH

A modern 6 MW wind turbine at a site with 55% site quality according to EEG 2023 achieves an actual remuneration of 7.95 ct/kWh due to the correction factor of 1.42 – with an award value of 5.6 ct/kWh. With around 2,200 full-load hours with night-time throttled operation, this results in an annual energy yield of 13,200 MWh and an annual turnover of just under 1,050,000 euros. In this example, however, the profitability threshold would only be a surcharge value of 5.9 ct/kWh – only 0.3 cents per kilowatt hour separate the project from implementation.

If unnecessary noise throttling is eliminated as part of an amendment procedure under the Federal Immission Control Act, the annual energy yield can rise to around 14,650 MWh – an increase of around eleven percent. The project will be economical.