Beaver Ridge Wind Sound Study – 2013
Because the noise generated by the Beaver Ridge Wind project was still an issue for some Freedom residents, Beaver Ridge Wind agreed to conduct another, longer sound study on four properties surrounding the ridge. This sound monitoring was conducted from November 19, 2013 to December 16, 2013 by a third-party sound consultant: Hessler Associates, Inc.
A good job was done describing the components of this study in a simplified format for those of us who need it. I’ve attached a copy for you to peruse at your leisure.
Things to note:
Primary Methodology: High Wind Shear
- Conditions specified by the DEP Sound Rules. (See 5.4-4, pg. 12)
- Will only produce valid periods if turbines are generating above 924 kW. (See 5.4-4, pg. 12)
- “The three turbines are generating above 924 kW, above which the turbines produce their highest sound power level (i.e. the turbines are at their loudest)” (See 5.4-4b, pg. 12)
Secondary Methodology: L90 to L10 Difference
- Dictated by the DEP Sound Rules if above method is not applicable. (See 5.4-5, pg. 12
- The study states, “For this time period, Turbine T3, the furthest turbine from the monitor was producing less than 924 kW.” (See 6.2 footnote, pg. 17)
Tertiary Methodology – Turbine Shutdowns
- Not part of the DEP Sound Rules and most commonly used outside of Maine. (See 5.4-6 pg. 13)
I did up a spreadsheet in excel to bring together all of the valid periods using the charts from the primary, secondary and tertiary methodologies from the four locations. Below is a sum up of the results.
- 28 days of testing.
- 12 days of testing available in the month of November 2013.
- 16 days of testing available in the month of December 2013.
- 12 days of valid periods were published from 4 separate locations on 2 different sides of the ridge.
- 3 days of valid periods fell within the month of November 2013. (Secondary & Tertiary Methodologies)
- 9 days of valid periods fell within the month of December 2013. (All 3 Methodologies)
- 4 days had valid periods that included both sides of the ridge.
- 4 days had valid periods using the primary methodology. (All in December 2013)
- 6 days had valid periods using the secondary methodology. (2 in November 2013; 4 in December 2013)
- 7 days had valid periods using the tertiary methodology. (1 in November 2013; 6 in December 2013)
- 1 day had valid periods consisting of all 3 methodologies. (All in December 2013)
|P = Primary | S = Secondary | T = Tertiary|
|G = Gerrish | L = Littlefield | SB = S&C Bennett | DB = D&M Bennett|
|Blue is the Gerrish/Littlefield side of the ridge | Yellow is the Bennett side of the ridge|
I am not arguing that the data presented within the study is inaccurate by the methodologies used. I am definitely not qualified to even attempt it. I’ll leave that to the experts. What I’m going to focus on is the time frame. Why?
One reason is that I, myself, don’t understand how a sound study can accurately determine the noise generated by the BRW turbines by studying 28 days out of roughly 7,300. (The projected life expectancy of the BRW project is for 20 years.) I’m sure that sound engineers may try to explain this phenomena to the satisfaction of some, but not to those who live near these industrial wind turbines year after year and are at the mercy of a very fickle lady – Mother Nature.
Squirrel: We did mentioned to Tom Carroll (Patriot Renewables, LLC, Outreach Coordinator), when he visited the Littlefield homestead prior to the sound study, that we are hit hardest on our side of the ridge during the spring and fall seasons and when the wind is blowing predominantly from a southerly direction.
Note that the majority of the valid periods were from the Gerrish/Littlefield side of the ridge and during the month of December. Also, note that both Bennett homesteads didn’t receive a full 28 days of testing. S&C Bennett because their equipment was installed after the testing started and D&M Bennett due to electronics failure.
Now lets discuss the Federal Energy Regulatory Commission (FERC) data we received. I’ve attached a copy of the six years of FERC data obtained for the Beaver Ridge Wind project below.
According to this FERC data, for the last quarter of 2013 the BRW project had is lowest capacity percent of production compared to any of the other 4th quarter months for all 6 years. It also shows that in December 2013 (the month that the sound study had the most valid periods) the BRW project had its lowest production of MWh compared to 4 previous years and 1 year after for the same month.
|Date||Production MWh||Qt Cap %|
Are these numbers the lowest numbers of production the FERC data shows? No, but the quarterly capacity % for the 4th quarter in 2013 is more comparable to the project’s capacity % during the 3rd quarters for all 6 years, than the other 4th quarter periods for all 6 years.
A few of the things that I’m having a hard time wrapping my head around:
- Why there were more valid periods in December versus November when according to the FERC data the turbines produced closer to their normal MWh in November?
- There wasn’t a single day that produced valid periods using the primary methodology occurring in November from any of the locations in 12 days of testing, even though the turbines were producing closer to their normal production of MWh? I didn’t see any valid periods listed in the charts provided for each locations primary methodology charts.
- Why was the BRW projects cap % for the 4th quarter in 2013 (when the sound study was being conducted) extremely low compared to all other years – before and after?
- How can an accurate study of the noise generated by these turbines be determined in 28 days out of 7,300 (the estimated number of days projected that the BRW turbines are expected to be operational)?
I’m sure there are other pertinent questions I should be asking, but it’s late and I’m calling it night. With all of the components put together, what would your assumption be regarding this sound study?
The Families have on many occasions discussed hiring a third-party consultant to do testing for us for a longer period of time – like a year. A testing that would encompass a wider range of variables gathered from a wider range of conditions for a longer period of time. I’m thinking that it’s time we pool our resources together and get this done. If nothing else, this study may result in us having a quieter year.