Puna Geothermal Venture, criticized for around-the-clock drilling earlier this year, plans to take extra steps to reduce its noise impact.
The geothermal plant in Puna, operated by Ormat Technologies, will install sound barriers around a drill the next time a well is constructed, said Paul Thomsen, Ormat policy and business development director.
Additionally, sound walls, already used around parts of the plant, will be expanded and a “hospital-grade muffler” will be placed around a truck-mounted drill to be used for well maintenance next month.
“There’s going to be almost no noise,” Thomsen said of the work that will occur around Thanksgiving.
“I doubt that anyone is going to hear it.”
The additional sound-proofing efforts come as PGV faces criticism for a drilling project that lasted 24 hours a day from March through July, and was loud enough to awaken neighbors.
In response, County Council chairman Dominic Yagong introduced legislation to prohibit geothermal well drilling at night, though whether or not it would apply to the plant, which has at least one existing permit for additional geothermal production, remains murky.
A public hearing on the bill will be held at 5:30 p.m. Friday in the Pahoa Neighborhood Facility. The council will take testimony but no action until its Nov. 9 meeting, Yagong said.
If approved, the bill would limit drilling that occurs within one mile of a residence to between 7 a.m. and 7 p.m.
PGV opposes the bill, saying stopping drilling for half the day would create safety issues and lengthen the projects. Its attorney has also raised questions as to whether it could apply to the plant since it has a permit from the Windward Planning Commission to expand geothermal power up to 60 megawatts.
It currently produces 34 megawatts.
Yagong said he agrees that legalisation can’t be retroactive, and therefore, can’t impact existing permits, but he notes it still could be enforced on any new permit PGV receives, possibly from other agencies that still have to approve new drilling.
“As long as the existing permit they have allows them to do certain things, it should not affect that,” he said. “It’s only if they go out for a new permit that’s not covered under existing permits would any of that then fall (under) the ordinance.”
In a voicemail, county Planning Director Bobby Jean Leithead Todd said she is unclear on what limitations the county can place on the permits.
“To me, there is a real question as to where the authority lies on that issue,” she said.
Corporation counsel hasn’t appeared to question the legislation but did raise concerns over it’s application to PGV.
In addition to plans to reduce noise, PGV is also changing the way it displays data on noise and hydrogen sulfide levels on its website.
Those changes, unveiled at a community meeting in Pahoa on Tuesday, will allow users to review historical data rather than the current 5-minute average.
Karen Breitlow, of Cardno TEC, PGV’s environmental consultant, said the information will be boiled down to the year, month, day and hour, though the data will still be based on averages of 5 minutes or more.
Some Puna residents at the meeting, attended by about 40 people, raised concerns over the continued use of averages.
“It won’t pick it up but I will pick it up in my home,” said Jon Olsen, referring to a large, single noise event.
Others said they think the noise limit of 70 decibels for the plant should be reduced. Thomsen said PGV usually stays well below that level.