Noise 1-1

RESPONSE:

As explained in Section 6.9 of our Energy Facility Siting Board Application, noise produced during normal operation of the CREC facility will comply with the A weighted limits in the Town of Burrillville noise Code of Ordinances. CREC must also conform to levels approved by the Rhode Island Energy Facilities Siting Board, (“EFSB”).  The Project performed an evaluation of the Town of Burrillville’s Code of Ordinances, as it relates to the noise performance standard in an effort to arrive at a noise level design goal that was both respectful of the Code’s intent to protect the community from excessive noise, yet commercially feasible to achieve and consistent with previous EFSB approvals. The Town of Burrillville noise Code of Ordinances, which generally limits both broadband (A-weighted) to an equivalent level of 43 dBA and specific octave-band Facility noise levels at nearby residences, (see Table 1 below). The Town of Burrillville’s Code, however, also states that is not applicable in instances where “[t]he facility generating the noise has been granted a permit or license by a federal and/or state agency and the authorization to operate within set noise limits”.  The CREC Project proposes to comply with the same stringent noise limit imposed by the EFSB on Burrillville’s Ocean State Power Project (and other EFSB approved projects), namely the broadband A – weighted limit of 43 dBA at the closest residence.

The Burrillville noise limits, specifically in the low-frequency octave-bands (31.5 Hz, 63 Hz, and 125 Hz), are among the most stringent that we have seen in the United States.  Compared to octave band noise limits used in other US jurisdictions (see Table 1), the Burrillville Ordinance is significantly more restrictive.  This is particularly relevant since low-frequency emissions are generally more difficult to mitigate than are high-frequency noise emissions.  Invenergy Thermal Development, LLC (“Invenergy”) examined the design approaches needed to comply with the Town’s octave band ordinance.  Achieving the broadband portion of the code (43 dBA) is feasible for normal operation modes, by using extensive controls as shown on Table 9, including placing the combustion turbines within buildings. Achieving the octave band limits was not feasible for all octave bands during normal or transient operating modes. Attaining the unusually restrictive octave-band limits was found to require extraordinary mitigation measures that were determined to be technically infeasible. Invenergy performed an evaluation of the noise produced during transient operating modes and the type of controls that would be needed to meet the broad band requirements. The Transient Noise Level Evaluation Report is included as Exhibit A.   For normal operations, the expected octave band noise is shown on Table 1, which shows the Clear River Energy Center (“CREC” or the “Project”) expected octave band and A weighted noise levels.  

As shown on Table 1, which is a summary of the data included in Appendix E, the CREC expected octave band limits are below the limits stated in the Town Code for all but three of the levels corresponding to the lower octave bands. The octave band noise limits listed for other US jurisdictions (Table 1), where found based on a search of similar ordinances that included octave band limits. The list is not presented as a complete list but rather as a representative list of ordinances that have such stipulations. The noise expected for transient modes of operation are discussed in the response to question 1.5.