Resource Documents: Regulations (251 items)

RSSRegulations

---

Review of noise guidance for onshore wind turbines: report for UK government

Author:  WSP

This study aimed to answer the question: in view of government policies on noise and commitments to Net Zero, should the existing ETSU-R-97 noise assessment guidance for wind turbines be updated, and if so, how?

Onshore wind is recognised as one of the lowest-cost sources of renewable electricity generation. A sustained growth in capacity is also seen as a keen enabler of the UK government’s commitment to deliver a net zero economy by 2050.

Using our expertise in acoustics, planning and environmental assessments for renewables, we delivered this study on behalf of the UK government Department for Business, Energy & Industrial Strategy (BEIS) to review the UK onshore commercial wind turbine noise assessment guidance (a document known as ETSU-R-97).

Since the ETSU-R-97 guidance was published in 1996, the context has changed:

• The need for onshore wind energy is more urgent
• Technology has advanced
• New research has been undertaken
• Understanding of wind turbine sound has progressed, highlighting in particular the potential impact of amplitude modulation (AM, described below)

Our report recommends key areas of the guidance that would benefit from being updated, and provides recommendations for further evidence needed to support updates identified. These include revisiting the framework of noise limits, and establishing new guidance to support assessment and control of the potential impact of AM.

Our recommendations will help to ensure that guidance for local planning authorities, developers and operators is the most relevant and up-to-date possible, supporting robust planning and assessment processes for managing the potential impacts of noise from wind turbines, which in turn will contribute to sustainable delivery of onshore wind energy.

How did we approach the study?

WSP’s acoustics team worked closely with a steering group including BEIS, the Department for Environment, Food & Rural Affairs (Defra), the Department for Levelling Up, Housing & Communities, the Scottish Government, the Welsh Government, and the Northern Ireland Executive.

The study comprised three workstreams:

• Evidence review
• Stakeholder engagement
• Field measurements

The evidence review employed two stages of systematic literature search and screening of a wide range of publications identified from peer-reviewed literature databases, scientific conferences, official reports, guidelines and standards. In total, 132 publications were reviewed for evidence relevant to the research.

The stakeholder engagement survey included a questionnaire, and focus interviews with identified key stakeholders. In total 32 organisations responded to the questionnaire and 6 key stakeholders were interviewed.

The field measurement exercise collected a ‘snapshot’ of wind turbine sound data from seven wind farm sites during conditions thought likely to enable the detection of amplitude modulation at ranges representative of wind farm neighbours.

What is amplitude modulation?

A feature of wind turbine sound commonly known as amplitude modulation (AM). This is a regular fluctuation of the sound level associated with the passage of the blades. It is often described subjectively as a ‘swish’ or ‘whoomph’ sound.

Areas for increased focus:

Our analysis indicates that the existing guidance would benefit from updating in two key areas:

1. Noise limits: The ‘noise limits’ defined in the ETSU-R-97 guidance are based on information that reflected the state of knowledge and turbine technology at the time. The research indicates that these should be revisited in view of advancements in onshore wind turbine technology, knowledge and scientific evidence of the potential impact of wind turbine noise, and the evolution of government noise policies in each of the devolved administrations of the UK. These developments could be reflected in a new framework for assessment and control of noise impact, in terms of addressing health outcomes and expected behavioural responses associated with wind turbine noise.
2. Amplitude modulation guidance: The research also indicates that the current ETSU-R-97 guidance does not fully address the potential impact of AM in wind turbine sound. The evidence identified in the study, including indicative information from the field measurements, suggests that the assumptions about AM adopted in ETSU-R-97 do not fully represent the nature of AM as experienced and measured. Existing evidence could be used to help develop suitable guidance on controlling AM, and stakeholder views suggest this would be welcomed.

Our report also includes recommendations on further areas of the guidance likely to benefit from updating to reflect the latest evidence addressing methods of measurement, prediction, data analysis, assessment and control for wind turbine sound and noise.

Recommendations for future studies:

Our report for BEIS identifies further key evidence needed to support some of the recommended updates, and to inform planning and consenting around onshore wind farms in the UK, including:

• A systematic review and meta-analysis of evidence on the effects of wind turbine sound exposure on noise annoyance and sleep quality,
• A more detailed review of national and regional guidelines applied in overseas territories to manage wind turbine noise,
• A study to consider the effectiveness of the current ‘relative impact’ approach to controlling wind turbine noise based on existing background sound environments,
• A study to consider the effectiveness of the ‘relative impact’ approach to controlling wind turbine noise and identification of effect thresholds.

Attaining suitably robust evidence to support guidance updates is likely to require government, industry, academia and other stakeholder groups to work together to achieve mutual interests in providing local planning authorities, environmental protection departments, developers and operators with the most relevant and up-to-date guidance possible for planning and assessing noise from wind turbines. Achieving this aim will ensure the effective management of the potential impacts of wind farm noise, while supporting government objectives for achieving Net Zero.

The findings of the study must be considered within the context of its strengths and limitations, which are detailed and discussed in the report. The authors would like to stress that this review represents only an initial step in any process of updating the existing guidance that may be decided on in the future; the report itself does not provide new guidance or supersede any parts of the current policy or guidance frameworks in place in any of the devolved administrations.

Download original document: “A review of noise guidance for onshore wind turbines”

---

Act relating to the siting and operation of certain wind energy conversion facilities

Author:  Iowa State Senate

3. a. A wind energy conversion facility shall be sited at the following distances:

4. a. Prior to the siting of a proposed wind energy conversion facility, the owner of the proposed facility shall notify the owner or operator of any registered or licensed tower used for emergency services communications which is located within a five-mile radius of the proposed location.

b. A wind energy conversion facility shall be sited at a location which does not interfere with any existing emergency services communication equipment or systems. If the facility interferes with any such communication equipment or systems, the owner of the facility shall take all steps necessary to mitigate the effects of the interference.

5. Prior to the siting of a proposed wind energy conversion facility, the owner of the proposed facility shall file a decommissioning plan with the county recorder of the county in which the proposed facility will be located. If the proposed facility will be located within two miles outside the corporate limits of a city, the owner of the proposed facility shall also file the plan with the city clerk of the city. The plan shall be accompanied by a bond or an irrevocable letter of credit in an amount sufficient to cover the costs of removal of the facility. This subsection shall not apply to a wind energy conversion facility owned or operated by a rate-regulated public utility.

6. A wind energy conversion facility shall be presumed abandoned if the facility fails to operate or be staffed for more than twenty-four consecutive months without generating energy. The owner of the abandoned facility shall be responsible for the removal of the facility, including the removal of infrastructure four feet below ground level.

7. This section does not prohibit a local authority from imposing additional or more restrictive regulations or requirements relating to the siting or removal of wind energy conversion facilities, except to the extent such regulations or requirements conflict with this section or any other provision of law.

8. This section does not prohibit a landowner from waiving any requirements under this section by conveying an easement or other property interest. …

Sec. 2. NEW SECTION. 476.50A Wind energy conversion facilities —— connection with electric distribution system.

1. A wind energy conversion facility, as defined in section 476C.1, which has a nameplate generating capacity greater than five hundred kilowatts shall not connect with the electric distribution system unless authorized by the board in a contested case proceeding pursuant to chapter 17A. The board shall set the case for hearing and give such notice thereof as it deems appropriate. The board shall, as part of its review, consider engineering studies conducted by affected public utilities.

2. This section shall not apply to a wind energy conversion facility owned or operated by a rate-regulated public utility.

EXPLANATION

This bill establishes new Code sections 476.50 and 476.50A, relating to the siting and operation of certain wind energy conversion facilities.

New Code section 476.50 provides certain siting requirements for wind energy conversion facilities which have a nameplate generating capacity greater than 100 kilowatts. The bill provides that it is the intent of the general assembly to: support the establishment and growth of renewable energy in Iowa through common sense regulations that ensure fairness; prevent regulatory manipulation efforts by unregulated entities; and encourage statewide uniform standards for the siting and development of wind energy conversion facilities in Iowa. The bill provides that it is not the intent of the general assembly to negatively affect renewable energy generation for private generation customers, rate-regulated public utilities, municipally owned utilities, or rural electric cooperatives.

The bill provides that a facility shall be sited at a distance no less than the greater of two and one-half times the total height of a wind turbine to be constructed on a proposed facility, as described in the bill, or 5,000 feet from any existing abutting dwelling or nonparticipating property, and at a distance no less than the greater of one and one-tenth times the total height of a wind turbine or 500 feet from any existing overhead utility line, electric substation, public road right-of-way, railroad right-of-way, or unoccupied structure. The bill includes definitions for “abutting dwelling”, “nonparticipating property”, “public road right-of-way”, “railroad right-of-way”, and “unoccupied structure”.

The bill provides that prior to the siting of a proposed facility, the owner of the proposed facility shall notify the owner or operator of any registered or licensed emergency services communications tower located within a five-mile radius of the proposed location. A facility shall be sited at a location which does not interfere with any existing emergency services communication equipment or systems. If the facility interferes with any such equipment, the owner of the facility shall take all necessary steps to mitigate the interference.

The bill provides that prior to the siting of a proposed facility, the owner of the proposed facility shall file a decommissioning plan with the county where the proposed facility will be located, and specified cities if applicable.

The plan shall be accompanied with a bond or irrevocable letter of credit in an amount sufficient to cover the costs of removal of the facility. This requirement does not apply to a facility owned or operated by a rate-regulated public utility.

The bill provides that a facility shall be presumed abandoned and shall be removed by the owner, including the removal of infrastructure four feet below ground level, if the facility fails to operate or be staffed for more than consecutive months without generating energy.

The bill provides that it does not prohibit local authorities from imposing additional or more restrictive requirements relating to the siting or removal of facilities, unless such requirements conflict with the bill or any other provision of law. The bill also provides that it does not prohibit a landowner from waiving any requirements of the bill with respect to siting.

The bill provides that it does not apply to wind energy conversion facilities existing on or before January 1, 2024, or facilities the construction of which is begun prior to January 1, 2024, and is scheduled for completion by January 1, 2025, as described in the bill. The Iowa utilities board may grant additional time for completion of such a facility for a period of up to 12 months upon a showing of good cause.

The bill provides that it does not apply to the repowering of a wind energy conversion facility existing on or before January 1, 2024, provided that the repowering does not violate the siting distance requirements contained in the bill.

The bill provides that the board may adopt rules to implement Code section 476.50.

New Code section 476.50A provides that wind energy conversion facilities which have a nameplate generating capacity of greater than 500 kilowatts shall not connect with the electric distribution system unless authorized by the board pursuant to a contested case proceeding, after notice and a hearing. In doing so, the board shall consider engineering studies conducted by affected public utilities. Code section 476.50A does not apply to facilities owned or operated by rate-regulated public utilities.

Introduced January 9, 2023.

Download original document: “An Act relating to the siting and operation of certain wind energy conversion facilities”

---

Industrial Wind Turbine Seismic Source

Author:  West, Michael

Introduction

Despite their generally positive reputation as sources of clean, safe energy, Industrial Wind Turbines (IWTs) do have their critics. For years, residents living in the vicinity of IWT clusters have reported a variety of physical ailments which they attribute to the sounds and vibrations emanating from wind turbines (Kelley, 1985; CBC.ca, 2011). Noise bylaws, setback distances and other regulations applied to IWTs appear to be based on analysis methods used historically with industrial applications, where noise tends to be constant or semi-constant and in the audible range. The noise generated by IWTs is quite different – spiky and high amplitude – like an exploration seismic source pulse, and mainly found in low frequencies not detectable by human hearing (i.e. infrasound or “below hearing”). This article looks at the signals generated by IWTs from a geophysicist’s perspective. …

Conclusions

The analysis of the operating IWTs on the ground and the seismic and air-pulse recordings confirms that large horizontal axis Industrial Wind Turbines act like airgun seismic sources that create low frequency pulses approximately once per second. The audible part of the air pulse makes a sound like “whump” so, as per geophysical industry tradition, we should name the IWT a “whumper” seismic source (as opposed to a thumper or puffer which would require a faster rise-time on the pulse). Most of the amplitude of the pulse exists at frequencies below the audible range, so a person stopping by the roadside to listen to an IWT may not hear anything and is likely to think that they make no significant “noise” at all.

Two aspects of IWT-generated noise do not appear to have been adequately accounted for in the creation of regulations for the IWT industry: that the noise contains many spurious, high amplitude spikes, and that it is mainly found in the low, infrasonic frequencies. An impulsive noise source such as an IWT requires amplitude measurements over short time windows like 1 second and little or no averaging of data during analysis. Long analysis time windows and averaging amplitude over 1/3 octave band frequency ranges is an acoustics industry testing method appropriate only for higher frequency “whirring” machines like diesel generators or milling machines. Current Ontario Government regulations do not include testing frequencies lower than 31.5 Hz. “Noise” testing procedures for regulation of IWTs should be revised to include all low frequencies created by the IWTs because the low frequency events contain the most power and highest amplitudes.

Conversion of non-weighted peak pulse amplitudes from the microphone recording in Figure 9, at 550 meters offset in 20 kph winds including the full frequency range to 1 Hz, revealed peak Sound Pressure Levels of 65 dB or more. Additionally, the SPL noise limit specification should not be increased with increased wind speed as this makes no sense. Governments and agencies tasked with the regulation of IWT installations should review and revise their testing protocols, so that regulations that reliably protect the health of people and animals living in the vicinity of IWTs can be implemented.

Michael West, P. Geoph., B.Sc., GDM

Canadian Society of Exploration Geophysicists | Recorder, Jun 2019, Vol. 44, No. 04

Download original document: “The Industrial Wind Turbine Seismic Source”

---

Why “Ground Factor” Matters

Author:  Overland, Carol

Minn. R. 7030.0400 is the MPCA’s noise rule, setting standards for industrial noise. It was developed to limit industrial noise, from a noise source on the ground to a “receptor” on the ground. ISO 9613-2 was also developed to measure ground based noise reaching a ground based receptor.

A primary input is the “ground factor” set to address conditions on the ground, the ground effect, between the noise source and the receptor:

7.3  Ground effect (A_gr)

7.3.1  General method of calculation

Ground attenuation, A_gr, is mainly the result of sound reflected by the ground surface interfering with the sound propagating directly from source to receiver.

While there may be some reflected sound reaching the “receptor” (that is such an obnoxious term for people!), the sound from a wind turbine with a hub height of 300 feet or more! That’s a direct path to the “receptor.” The ground, grasses, corn, trees, buildings, do not get in the way.

The ground factor to be used for wind turbines is ZERO.

Dr. Schomer stated this clearly and thoroughly in the Highland Wind docket in Wisconsin (PSC Docket 2535-CE-100).

Download  Schomer Pages from Transcript Vol 4 (see page 572)

The use of a 0.0 ground factor for wind is standard practice, and that a 0.5 ground factor is NOT appropriate for wind because it’s elevated. This was inadvertently confirmed by Applicant’s Mike Hankard in the Badger Hollow solar docket, also in Wisconsin (PSC Docket 9697-CE-100):

The model that we use has been shown to predict conservatively with 0.5. I mean, 0.5 ground factor is used in probably – well, with the exceptiion perhaps of wind turbine projects which are different because the source is elevated. But for projects like a typical power plant, a solar plant where the sources are relatively close the ground, I would say 90 to 99 percent of the studies use 0.5. And when consultants like myself go out ad measure these plants after they’re cpmnstricted tp verify our modeling assumptions, that assumption checks out as being, if anything, overpredicting the levels. So there’s no need to – there would be no justification to use something like a .2 or .3 which would predict yet higher levels because we’re already demonstrating that the model is probably overpredicting. So that would not be justified for those reasons.

Who cares? Well, it’s bad enough that in that WI PSC Highland Wind docket, when the applicants couldn’t comply with the state’s wind noise limit, they redid their noise “study” using the inappropriate ground factor of 0.5 to give them more compliant numbers – they moved the goal posts, garbage in, garbage out. They think they can do that in Minnesota too, and are trying oh so hard in the Freeborn Wind docket (PUC Docket 17-410).

Last September, 2018 that is, Freeborn Wind did a deal with Commerce, admitted to in its “Request for Clarification/Reconsideration” pleading:

Freeborn Wind requests the Commission clarify its Site Permit to adopt Section 7.4, as proposed by Freeborn Wind and agreed to by the Department and MPCA, in place of the current Sections 7.4.1 and 7.4.2, to both ensure consistency with the Order and avoid ambiguity in permit compliance.

Freeborn Wind’s September 19, 2018, Late-Filed proposal for Special Conditions Related to Noise outlines the agreement reached between Freeborn Wind, the Department and the MPCA on this issue.

(fn. citing Late Filed—Proposed Special Conditions Related to Noise (Sept. 19, 2018), eDocket No. 20189-146486-01).

In this deal, they put language in the permit that was a fundamental shift in noise monitoring, one for which there is no justification under the noise modeling standards, whether state or ISO 9613-2 – that of using a 0.5 ground factor.

The language in the proposed special conditions requires Freeborn Wind to submit updated modeling and/or proposed mitigation demonstrating that modeled wind turbine–only noise will not exceed 47 db(A) L₅₀-one hour at receptors. Specific guidance is included regarding the modeling assumptioins to be used. Specifically, proposed Section 6.1 directs Freeborn Wind to follow the NARUC ISO 9613-2 standard with a 0.5 assumed ground factor. As reflected in the special condition language, setting a turbine-only noise limit at 47 dB(A), using the specified model assumptioins, ensures that the Project will not cause or significantly contribute to an exceedance of the MPCA Noise Standards. This limit is supported in this record by expert testimony from Mr. Mike Hankard and the MPCA’s 2015 Noise Guide, both stating the 3 dB(A) is the generally recognized minimum detectable change in environmental noise levels. To illustrate, when nighttime background sound levels are at 50 db(A) L₅₀-one hour, a maximum turbine-only contribution of 47 db(A) L₅₀-one hour would result in a non-significant increase in total sound of less the 3 dB(A).

The day before the Commission’s meeting, they filed for a “Special Condition,” and oh, was it special:

Download  20189-146486-01_LateFiling

At the meeting, they presented a chart with made up numbers on it, not supported by any noise study:

This chart was shown for a few seconds at most, it was not provided in the “Late Filing” above, and there were no copies for parties or the public. Did Commissioners get a copy? Who knows …

The Commission then granted the site permit! There were a few rounds before we got to where we are today, with Xcel Energy acquiring the project, and with a new site plan, bigger turbines, and some specific site permit amendments. In its permit amendment application, Xcel Energy is now the owner of Freeborn Wind, and Xcel wants to use larger Vestas V120 turbines rather than the V116.

From testimony in the original Freeborn Wind hearing, and in an Affidavit submitted by Commerce-EERA’s Davis:

7.  It is generally understood that turbine noise output increases with higher blade tip speeds …
(Aff. of Davis, EERA Motion, 20181-139379-01)

In its permit amendment application, Xcel Energy is now the owner of Freeborn Wind, and Xcel wants to use larger turbines. In so doing, they have filed a noise study, Attachment E, utilizing that 0.5 ground factor. Xcel’s claim is that they’re using a 0.5 ground factor because the permit specifies that:

This Xcel filing is the first noise study in the Freeborn Wind record to utilize a 0.5 ground factor.

This Xcel filing is the first noise study in the Freeborn Wind record following the ALJ’s recommendation of denial:

The Administrative Law Judge concludes that Freebron Wind has failed to demonstrate that the proposed Project will meet the requirements of Minn. R. 7030.0040, the applicable Minnesota Noise Standards. Therefore, the Administrative Law Judge respectfully recommends that the Commission either deny Freeborn Wind’s Application for a Site Permit, or in the alternative, provide Freeborn Wind with a period of time to submit a plan demonstrating how it will comply with Minnesotat’s Noise Standards at all times throughout the footprint of the Freeborn Wind Project.

There’s a 3 dB(A) margin of error – even using Hankard’s numbers, look at the yellow lines right up against the homes, and look at the blue 50 dB(A) lines and how many homes are inside of those lines:

Turbine noise at the hub for the V120s can be maximum of 110.5 dB(A), and serrated edges provide an option to reduce noise (which Xcel says it plans on using for some turbines), per the Vestas spec sheet.

Compliance? Modeling with the improper 0.5 ground factor doesn’t come close to demonstrating compliance, instead it demonstrates a high probability of non-compliance. It demonstrates that using the proper ground factor for wind, it won’t do the modeling, likely (assuredly) because the project cannot comply. Freeborn Wind could not demonstrate that it could comply with state noise standards as originally designed with the smaller wind turbines and the proper modeling ground factor, and now Xcel Energy wants to use larger turbines. Larger turbines are noisier … once more with feeling:

7.  It is generally understood that turbine noise output increases with higher blade tip speeds …

And now we see, hot off the press, the Plum Creek wind project (PUC Docket WS-18-700), proposed by Geronimo …

Vestas 150 and 162 turbines, 5.6 MW each! The noise for the V150 is a maximum of 104.9 dB(A), and for the V162 is a maximum of 104.9 dB(A), with “sound optimized modes available.” That’s in the brochure.

They have provided a noise study, BUT, much is NOT PUBLIC:

201911-157475-05_Noise_Appendix B

And I wonder why … well, it says that they’re not using a ground factor of 0.0. Look at p. 48 of the sound study above, deep breathe and take a peek:

They’re using a ground factor of 0.7 !

Really …

For this analysis, we utilized a ground factor of G=0.7, which is appropriate for comparing modeled results to the L₅₀ levels.18 A 2-dB uncertainty factor was added to the turbine sound power per typical manufacturer warranty confidence interval specifications.

18 Generally accepted wind turbine modeling procedure calls for a ground absorption factor of G=0.5, with a 2-dB uncertainty factor added to the manufacturer’s guaranteed levels, to predict a maximum L_EQ(1-hr). In this case the state limit utilizes and L₅₀ metric instead of maximum L_EQ(1-hr), which means a ground factor of G=0.7 can be used.

FALSE!

They say it again on p. 62, elsewhere too:

How stupid do they think we are?

How stupid do they think Commerce-EERA is? … oh … never mind …

Anyway, here are the sound study maps based on that bogus 0.7 ground factor – look how many homes are affected:

Geronimo gets the gong:

The applicants know exactly what they’re doing.

At least twice in the Freeborn record I have asked whether the Commissioners understand “0.5 ground factor” and “0.0 ground factor” and have been vigorously assured that yes, they do understand. And Commerce-EERA staff? You’re responsible for doing the footwork on these siting applications. Do you understand?

If they do not understand, or misunderstand, they’ve got some learnin’ and edumacation to do. If they DO understand, and are approving site permits knowing that the modeling is off, that ground factor is misused, they’re complicit. They’re knowingly afflicting those who have to live with the noise sound levels that exceed Minnesota state standards.

As we saw in Bent Tree, where the noise standard compliance is in question, it is Commerce’s job to do the noise monitoring and deal with the problem. Once a turbine is up, there aren’t many options other than “shut down the turbines” or “buy out the landowners.” How many landowner buy-outs do you think we need before it’s admitted there’s a problem? Why is it so hard to develop responsible, precautionary, and respectful siting? Why is there resistance? The costs of their failure to do so are … well … we may see exactly what those costs are.

Commissioners and Commerce staff, make sure you know how the state noise standard and ISO 9613-2 was designed, how it is to be used, and what ground factor means.

If you know what it means, and are siting turbines using 0.5 and 0.7, you are responsible.

—Legalectric, November 17th, 2019

---

Earlier Documents »

Click here to send in ordinances, contracts, research, testimony, presentations, etc.
Or see Contact page for more anonymous options.