Noise Level regulation for Solar

The Sept 2021 JPC solar draft ordinance’s noise and Vibration section set unrealistically low noise limits. If adopted, no solar farm will be able to function, and Maysville and Mason county will lose solar’s economic and ecological benefits.

Let’s look at each paragraph of Sept 2021 JPC Solar regulation draft Section 414.09 (b) as proposed :

(1) No SES or ancillary structure shall be located so as to create a decibel level greater than 30 dBa at the property line of the parcel in which the turbine is located and also less than 50 dB(C) at the property lines of the parcel in which the turbine is located.

Let’s start this discussion by reviewing the Db(A) levels of some familiar activities:

140 dB Threshold of pain Jet Engine at take off
110 dB Angle Grinder
100 dB Nightclub Motorcycle
90 dB Lawnmower
85 dB Compliance A weighted noise levels for NSW  WHS Regulations
80 dB Alarm clock
75 dB Vacuum cleaner
70 dB Taking a shower
60 dB Normal conversation
40 dB Running water of a creek
30 dB Library
20 dB Leaves from the wind
10 dB Pin dropping
0 dB Threshold of hearing
Sound levels of familiar activities

The absurdity of a 30 Db(A) limit seems obvious when we realize it means the solar farm boundary must be no louder than a library. Because Decibels are logarithmic, sound pressure increases 10 times, when the Db (A) rating increases 10 points. Under this proposed regulation, two people having a normal conversation, of 60 Db (A), on the boundary will be 1,000 times above the proposed regulatory limit. If a typical lawnmower is used around the boundary screening of a solar farm, its 90 Db (A) sound level will be 1,000,000 times above the 30 Db(A) requirement.

In fact, little to no noise will cross a solar farm’s perimeter. But people will need to talk and lawnmowers will occasionally need to be run. As written this rule makes either activity illegal near the perimeter of a solar farm.

It’s nearly impossible to draft specific decibel levels, in a noise ordinance, that are enforceable. This is one reason why no current Mason County land-use has such a requirement.

It is instructive to review the number of Solar ordinances that opted to NOT regulate sound:

KY PSC Siting board Case number 2020-00206 dealt with the AEUG FLEMING SOLAR, LLC application for a certificate of construction of an approximately 188 Megawatt merchant electric solar generating facility in Fleming County. In that case, the board ruled on sound, in Appendix A, that:

  • AEUG Fleming should coordinate a plan for noise buffering as needed for at least the 23 residences (and the Hunters Trace neighborhood) estimated to experience noise levels of 50 dBA or greater during facility operations. Additional vegetative buffering or fencing should be considered on an as-needed basis for residents who experience annoying and verifiable noise levels during operations.
  • The closest that an inverter can be located to a noise sensitive receptor should be 739.
  • The closest that a solar panel can be located to a noise sensitive receptor should be 265 feet.
  • The closest that the substation transformer can be located to a noise sensitive receptor should be 1,600 feet.

Note that because the KY PSC Siting board considers this specific solar farm in its locale it was able to ensure that specific farm respects noise-sensitive areas in its particular locale This is another example of how a Conditional Use Permit process increases the chance each solar farm will be designed to best serve Mason County as a whole. Global one requirement fits all situations (like the sound requirements in the 2021 Solar Draft Ordinance) serve only to kill any chance of solar delivering economic and ecological benefits to Mason County.

Given the difficulty of regulating noise levels and since the KY PSC Siting board has already assembled the technical expertise, and has legislative authority to ensure solar farms do not adversely impact noise-sensitive areas it is appropriate to not duplicate their effort.

By not duplicating the KY PSC Siting board’s efforts these sections of the Sept 2020 Solar Draft proposal are superfluous and not needed.

41.09 (B) (2) The application shall include a pre-construction sound study that establishes the ambient sound conditions in the proposed project area and surrounding the project area with a perimeter of one mile. The sound study shall be performed by a certified independent acoustical engineer. The sound study must provide a description of the testing, sampling and process methodology used in determining the ambient measurement. The firm with which the engineer is associated shall be a member of the National Council of Acoustical Consultants (NCAC) with a specialty in environmental noise, and the independent acoustical engineer shall be a Member, Board Certified of the Institute of Noise Control Engineering of the USA.

41.09 (B) (3) Within twelve months after the date when the project is fully operational the operator shall conduct a two phased post-construction sound study conducted by an independent accredited sound engineer chosen by the Planning Commission and paid for by the applicant/owner. Post-construction sound level measurements shall be taken both with all solar arrays running and with all solar arrays off. The post-construction measurements shall be reported to the Planning Commission and made available for public review.

41.09 (B) (4) If sound measurements from the post-construction analysis show levels above what is permitted by the ordinance, the operator shall take all necessary steps to remediate the problem.