Around 100 opponents of a wind farm under construction in Kahuku packed a state Public Utilities Commission hearing Friday to silently witness three attorneys arguing over a regulatory challenge to upend the project.

Yet many in the crowd opposing the Na Pua Makani project still delivered a message by wearing yellow pieces of duct tape over their mouths during the 45-minute hearing, at which no decision was made.

On some of the yellow strips, handwritten messages said, “Our voices matter” and “Environmental justice now.”

Other statements over taped mouths included “People > profit” and “Kahuku lives matter.”

The turnout at the PUC hearing inside the downtown Territorial Office Building, also known as Kekuanaoa, was the latest demonstration against the wind turbine project by Virginia-based AES Corp.

AES on Wednesday finished taking all the pieces for its eight turbines to the project site for assembly after five weeks of overnight truck deliveries from Kalaeloa that were met with demonstrations in which 200 people were arrested.

At the Territorial Office Building on Friday, at least 20 law enforcement officers were present, but all the action was from attorneys seated inside the hearing room addressing the commission’s three members.

Environmental organization Life of the Land filed a motion in September seeking to invalidate the PUC’s 2014 approval of a power purchase agreement between Na Pua Makani and Hawaiian Electric Co.

Lance Collins, an attorney representing Life of the Land, made three primary claims.

One is that the PUC didn’t consider impacts from greenhouse gas emissions tied to the project as it should have.

Another claim is that Na Pua Makani didn’t have control of the project site within 120 days after the PUC approval because the project had yet to obtain a permit for incidental kills of Hawaiian hoary bats.

Collins also argued that the rate to be paid by HECO for electricity from Na Pua Makani, 15 cents a kilowatt- hour, isn’t prudent or in the public interest.

“Hundreds of community members have submitted public comments in support of this motion,” he said, calling such support pretty unprecedented for a case before the commission that regulates utility companies, interisland shipping and passenger ground transportation services.

Randall Whattoff, an attorney representing HECO, disputed the claims by Life of the Land and also said the organization, which was involved in the power purchase agreement as it was being considered by the PUC in 2013 and 2014, failed to file a timely appeal. The pending motion, Whattoff said, is too late.

“This is just an attempt to re-argue something that has already been carefully considered by the commission,” he said.

Whattoff also noted that many health-related concerns mentioned in public testimony, such as spinning turbine blades causing shadow flicker and noise, pertain to issues that are the purview of other agencies and not the PUC.

Many Kahuku residents say the project is too close to the population. The closest turbine, rising 568 feet, would be 0.3 mile from the nearest homes and Kahuku Elementary School, and 0.1 mile from farms where people live.

AES claims that its wind turbines will produce noise about as loud as “light traffic” for the closest population and will have no ill health effects.

The third attorney addressing the PUC on Friday was Lane Tsuchiyama, representing the state Division of Consumer Advocacy.

Tsuchiyama opposed Life of the Land’s motion, in part for some of the same reasons cited by HECO. He also raised a concern that invalidating a power purchase agreement five years after approval could set a “monumental” precedent that could lead future energy project developers to offset risks for distant future challenges by seeking higher rates that cost consumers more if the PUC sides with Life of the Land.

PUC Chairman Jay Griffin said commissioners will take the oral arguments, which complement hundreds of pages of written briefs and public comments, under advisement and issue a written decision at a later date.

Meanwhile, AES continues assembling its turbines on land leased from the state Department of Land and Natural Resources and anticipates starting energy production next summer.