Firefighters doused two power poles threatened by lava with water and foam Wednesday to help protect them from temperatures that can exceed 2,000 degrees.
Firefighters doused two power poles threatened by lava with water and foam Wednesday to help protect them from temperatures that can exceed 2,000 degrees.
The poles along Apaa Street and Cemetery Road are among six Hawaii Electric Light Co. surrounded with cinder and insulation as part of an experimental effort to protect them from the June 27 lava flow.
But it is hoped that keeping them soaked as lava nears will increase their chance of success.
Rhea Lee, HELCO administration manager, said Wednesday it was likely the last opportunity to spray the poles before lava makes them impossible to reach.
Water and foam were also sprayed on a pole that began to burn from its base late last month. Lee said that appeared to reduce the heat and keep the pole from being lost.
Still, transmission lines were disconnected from that pole a couple weeks ago and two steel poles, including one that was sprayed Wednesday, were installed to extend the wire span from about 300 feet to up to 800 feet.
The steel poles are also more likely to withstand the heat.
Lee said protecting utility poles from lava is uncharted territory and not every attempt to save them will work.
“We knew going into this that pole protection was experimental,” she said. “No one has ever done it before. We probably won’t be successful at least on the first one. But we’re learning.”
The poles support one of two transmission lines in and out of lower Puna.
Another goes through the Hawaiian Beaches community, Lee said. If one is lost, the other will be able to take its place.
One challenge HELCO is facing is inflation of the lava flow.
Inflation occurs when lava builds under the outer crust, pumping it up like a balloon. Lee said the flow has inflated as much as 18 feet near the poles.
Protective material placed around the poles reach as high as 17 feet.
Lee said inflation was taken into account in the design.
“We had previously been told the highest inflation seen was 15 feet,” she said.
“That is something we continue to monitor as best we can.”
If both transmission lines are lost, HELCO plans to use two 1.2-megawatt diesel generators to supply power to as much of its customers in lower Puna as possible.
A spokesman for Puna Geothermal Venture said the 38-mgw plant planned to shut down if the transmission lines are lost.
Lee said HELCO continues to speak with PGV about the possibility of it serving a micro grid.
Flow update
Fingers of lava continued to flow down a small embankment into the closed Pahoa waste transfer station where it was burning asphalt Wednesday.
Darryl Oliveira, Hawaii County Civil Defense administrator, said lava was not advancing far from the perimeter fence and was not contacting any structures at the $3.95 million facility.
He described smoke conditions as moderate to heavy Wednesday but noted winds were helping to keep air clear over populated areas.
Meanwhile, a lava breakout mauka of the transfer station advanced another 225 yards as of Wednesday morning. Oliveira said it could reach Apaa Street in three to five days if it maintains its current rate.
Lava continued to be active on property off Cemetery Road where a house was destroyed on Monday. Oliveira estimated that breakout has advanced about 70 yards since Monday.
Except for a small garden shed on that property, no other structures have been destroyed this week.
That lobe remains about 400 to 500 yards from the nearest residence, Oliveira said.
The flow front remains stalled 480 feet from Pahoa Village Road.
County Department of Environmental Management closed the transfer station Oct. 24 as lava approached. Equipment and garbage and recycling bins were relocated to a temporary site behind the Pahoa Community Center.
The transfer station was finished in 2011.
With use of recycled construction material, rainwater collection and solar power, the facility was seen as a model for other transfer facilities around the Big Island. It also included a small community gathering place and bamboo information kiosk.
In 2012, Environmental Management received the Solid Waste Association of North America’s bronze award for the facility’s design.
Email Tom Callis at tcallis@hawaiitribune-herald.com.