By COLIN M. STEWART
and TOM CALLIS
Tribune-Herald staff writers
Hawaii County firefighters worked Wednesday evening to assess whether any threat was posed to area residents in Kapoho after the Puna Geothermal Venture plant went offline and vented steam for 15-20 minutes.
Two fire department crews with air monitors canvassed Pohoiki Road and Leilani Estates at about 5:15 p.m., doing air quality monitoring. A fire department spokesman said that all results weren’t in, but that readings taken at the entrance to PGV had so far found no hydrogen sulfide, a potentially deadly byproduct of the geothermal process.
Later in the evening, PGV Plant Manager Mike Kaleikini reported that during the event, a peak reading of 19 parts per billion of hydrogen sulfide was measured at the plant. He noted that was far below the permitted hourly limit of 25 parts per billion.
“The plant tripped offline, a little bit before 4 p.m., and we do not know exactly why at this point,” he said. “We’re still investigating.”
He added that all wells were shut within about 20 minutes of the power outage, but that during that time, steam was released from the plant’s Emergency Steam Release System.
The last time the plant experienced an unscheduled venting of geothermal steam was in November 2011, Kaleikini said.
“While there is no danger to the public, some residents have reported the presence of hydrogen sulfide odor,” according to an alert issued by Hawaii County Civil Defense at 5:12 p.m. “… The Department of Parks and Recreation has opened the Pahoa Community Center for residents who prefer to remain outside the area.”
Power was briefly knocked out to Puna residents as a result, Kaleikini said. Hawaii Electric Light Co. began feeding power into the area to make up for the shutdown at PGV, which was operating on backup generators, said.
Area resident Jeana Jones said she was driving on Pohoiki Road when she saw the steam plume, which she described as “screaming loud.” She said she knew immediately that it was coming from PGV, but wasn’t sure of the cause.
“I was absolutely concerned,” she said.
Jones added that she could smell a faint odor of hydrogen sulfide.
Last summer, Hawaii County’s Planning Department received a record 25 applications from homeowners living near the plant looking to sell their homes to the county and relocate as part of a program established for residents who have concerns about residing near a geothermal operation. None have been processed so far.
Five relocations have been approved in past years, with the most recent being in 2012.