One of our projects, Minnesota Municipal Power Agency’s (MMPA’s) Shakopee Energy Park, won Power Magazine's 2017 Gas Plant of the Year Award due to its community acceptance and quietness - even with residents located only a few hundred feet away. "MMPA did such a good job designing the plant to operate in the center of the community that “[w]hen speaking with residents, I’ve been told that they did not even know that we were up and running because they didn’t hear a thing,” John Crooks, Shakopee Public Utilities manager, said.

Power Acoustics, Inc was involved at all design stages beginning with a conceptual greenfield site to the detailed acoustical design of the facility. At the project conceptual stage, we obtained ambient sound measurements and performed preliminary noise modeling analysis. The analysis enabled us to set sound level goals to assure negligible community response. We then did the detailed acoustical design and specified noise abatement. After several iterations with the plant's design engineers, we settled on the final noise control (including the acoustical design of building walls, roof, ventilation silencing, radiator design and engine mufflers) to assure that the Shakopee Energy Park performed as acoustically intended.

For several of our projects, Power Acoustics, Inc. has measured, analyzed and developed noise abatement designs for steam generated noise observed during a combined cycle power plant's start up, shutdown, steam bypass and intermittent conditions. These operating conditions are often ignored by many EPC contractors but can be serious community noise problems. Steam generated noise is extremely loud and has even been described as "sounding like a Saturn V Rocket during liftoff." Steam noise issues are exacerbated with combined cycle power plants using Air Cooled Condensers (ACC) and have occurred in projects utilizing the smallest to largest combustion (gas) turbines - including GE Frame 7H plants.

Power Acoustics, Inc. has designed mitigation for many steam bypass and vent noise problems and resolved many community noise issues.

Power Acoustics, Inc. participated in all project stages beginning with the conceptual greenfield site, to detailed plant acoustical engineering, to performing the community noise testing at the facility's completion. At the project conceptual stage, we obtained ambient sound measurements and performed preliminary noise modeling analysis. The analysis enabled us to set sound level goals to assure negligible community response and assure project approval. We later performed a full facility acoustical design study for the Architect/Engineering firm and completed the project with sound level compliance testing. The facility coexists within the community with no known complaints from any nearby neighbors. Power Acoustics, Inc. has performed many combined cycle power plant acoustical design projects from smaller GE LM6000 based plants all the way up to GE Frame 7H plants.

Power Acoustics, Inc. participated in all project stages of a new Combined Heat and Power Coal Facility beginning with a conceptual site adjacent to the University's existing facility. At the project's conceptual stage, we obtained ambient sound measurements and performed preliminary noise modeling analysis enabling us to set sound level goals to assure negligible University and community response. We later performed a full facility acoustical design study for the project's engineering firm and completed the project with sound level compliance testing. The facility coexists within the community with no known complaints from dorms, classrooms or nearby neighbors.

Power Acoustics, Inc. participated in measuring the pre-installation sound of an existing mid-west Coal facility prior to installation of a SCR. The goal set was not to increase existing sound by more than 3 dB(A). Power Acoustics, Inc. created a computer noise model of the SCR and facility and determined the necessary noise controls to assure it didn't exceed the noise goal. We confirmed the facility met objectives with a post-SCR installation noise test.

Power Acoustics, Inc. has worked with several projects implementing various different types of Air Quality Control Systems (AQCS) retrofit upgrades including Dry and Wet Electrostatic Precipitator (DESP, WESP), Pulse Jet Fabric Filters (PJFF) and Flue Gas Desulphurization (FGD).

Power Acoustics, Inc performed an evaluation of the site and found tonal noise sources and sound levels in excess of 110 dB(A) in front of the inlet filter house. Complicating the issue was an asymmetrical ducting arrangement that impeded flow from entering one side of the existing vertically aligned silencer. Power Acoustics designed a retrofittable muffler that improved flow distribution in a short (4 foot) section of empty ducting located upstream of the original silencer. Although the retrofit silencer was approximately 1/3 the length of the original, it provided an additional 20 dB(A) of insertion loss and reduced sound levels to an acceptable level. Power Acoustics, Inc. has designed hundreds of successful air inlet and exhaust gas silencers for both end users, such as the utilities, and OEM manufacturers that supply silencing to major gas turbine manufacturers like GE and Siemens.

This facility was in the middle of an industrial park with no residential or commercial zones within several thousand feet. We designed the least expensive noise control available consisting of a sound wall adjacent to the property line - just to meet the local noise ordinance. The facility achieved the requirements with a 1 dB(A) margin.

Sometimes the plant is just too close to the neighbors. We evaluated this facility and developed extensive engineering design modifications to achieve the noise goals.

Power Acoustics, Inc was involved at the power plant design/construction stages by evaluating the design for the Architect/Engineering firm. The critical low frequency sound pressure levels were achieved at all residential locations. Although ignored by many acoustical consultants, low frequency noise, or infrasound, can be observed as vibration in homes and is often the primary complaint from neighbors located near gas turbine installations.

Power Acoustics, Inc. typical involvement is related to projects in need of special use permits or zoning approvals. However, we also perform work in eminent domain issues, criminal cases, and various other situations requiring acoustical expertise. Our most notable case as an expert witness was related to an existing power generation facility that was located in a fully industrial zoned location. An empty property adjacent to the power plant site was slated for use as a balefill operation. However, the balefill property was later sold to a housing developer wanting to build homes several hundred feet from the power plant. Working for the utility's lawyers, we successfully presented testimony and sound test data that supported a modification to the existing state noise regulations. Although the state's attorney general opposed the petition, the pollution control board accepted our client's request and issued a revision to the noise regulation requirements for the client's facility. Prior to this ruling, no changes had been issued by the state since the 1970's.