Lava could threaten electrical grid

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Fresh from restoring power to thousands of lower Puna residents after Tropical Storm Iselle, Hawaii Electric Light Co. is prepping for the possibility of outages wrought by lava from Kilauea volcano.

Monday evening, scientists with the Hawaiian Volcano Observatory predicted that lava from the June 27 flow could reach Pahoa Village Road within 18 days, and that would bring the flow close to two important transmission lines serving lower Puna, according to HELCO spokeswoman Rhea Lee.

Should one or both of those transmission lines be impacted by the continuing lava flow, how would the utility maintain or restore power?

“That’s the million-dollar question,” Lee said Tuesday.

Under the guidance of Hawaii County Civil Defense, HELCO is closely monitoring the lava flow, Lee said, and is weighing its options in preparation for the lava’s possible encroachment on electric lines.

“It’s hard to say anything with certainty at this point,” she said, “because we don’t know where it’s going. … Safety is our first priority. It always is, both for our employees and our customers. … We want to supply power to our customers for as long as we can, and that means knowing where (the lava) is today, and where it’s going, and what it’s doing on a daily basis. We’re tracking the flow and also looking to protect company assets.”

“It all depends on what the lava does,” she said. “If the lava is heading toward transmission lines, we have one response we need to focus on. If the lava is headed toward a substation, we have something else we need to do.”

Should the flow threaten poles and electric lines, for instance, HELCO is considering ways to allow the utility lines to span the width of the flow, particularly if it remains as narrow as it has been the past few weeks, Lee said.

“We can hope for a ‘smart flow’ that will flow in between the poles, and between houses and businesses and the highway. But that’s probably not what’s going to happen,” she said.

Should the flow take out a utility pole, workers can possibly take up slack to “float the line” across the flow’s span, maintaining electrical service to customers. Such a scenario could be improved by lengthening poles on either side of the flow, giving the line more room for slack.

“But until it gets close enough, we’re not sure what we can do,” Lee said.

If both of HELCO’s main transmission lines in the area are cut, power could possibly be lost to homes and businesses from Pahoa down to Kalapana, she said. There are no transmission lines coming from the south or Kona.

“This is the first time I recollect that so many people could possibly be impacted,” Lee added. “Although there were some facilities covered by lava when it entered the Kalapana area, there was a small number of people living in Kalapana as opposed to the surrounding communities (currently threatened).”

Email Colin M. Stewart at cstewart@hawaiitribune-herald.com.