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Pitch versus Stall — A Red Herring in the IWT Noise Debate

May 19, 2012

According to South Coast Today reporter Ariel Wittenberg, “Officials caution against comparisons between Fairhaven, Falmouth turbines.”

Falmouth’s Wind 1, the turbine shut down by the DEP, is a “stall-regulated turbine,” which Shah said “are louder than pitch-regulated turbines.”

Sumul Shah is the developer of Fairhaven Wind. At a blade-signing publicity event in March, Shah refused to comment on a resident request that he post a bond guaranteeing no health effects on abuttors. Shah maintains that Fairhaven’s turbines will not exceed noise regulations. Wittenberg goes on to describe Shah’s comments,

…different kinds of turbines are louder than others depending on the type of mechanism that controls rotor speed and blade tilt. Both Fairhaven turbines are “pitch-regulated,” as is Falmouth’s Wind 2, also built and controlled by Shah.


DEP Commissioner Kenneth Kimmel confirmed that different types of turbines operate at different noise levels and that turbines from different manufacturers also differ in noise level.

Howard Gostin’s analysis of pitch- vs stall-regulated turbine noise based on DEP report data

What the article fails to do is find an independent party who can comment from expertise. While not uninterested, chemical engineer and researcher  Howard Gostin refuted these claims with the DEP’s  own data*, demonstrating that pitch-regulated turbines are actually louder than stall-regulated. He offered his evidence in testimony at the hearing in Bourne on February 16. Gostin’s analysis has been confirmed by acousticians Robert Rand and Stephen Ambrose.

*The graph is derived from information in Appendix A and Appendix F and discussed in the text on page 5 of the report.

One Comment leave one →
  1. Chris Kapsambelis permalink
    May 20, 2012 1:31 pm

    Mr. Shah can’t tell us how much noise his turbines make. The MassDEP Wind Turbine Impact Study says that a typical wind turbine makes 106 dB(A) of noise, which is enough to hurt people. Wind I in Falmouth is rated for 103 dB(A), 3 dB(A) below typical. People live 200 feet closer to Mr. Shah’s wind turbines than the folks in Falmouth.

    One need not jump to conclusions. All we need here is the application of simple logic and arithmetic to conclude that when Mr. Kimmell is forced by complaints to test Mr. Shah’s turbines using the same, if not better, methodology as in Falmouth, Mr. Shah;s turbines will have to be shut down. Let’s hope it does not take Mr. Kimmell 2 years to do his duty as it did in Falmouth.

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