In Hawaii, lava flowing from the Kilauea volcano has led to the shutdown of the Puna Geothermal Venture (PGV) power plant. The 38-megawatt (MW) facility is the only geothermal plant on the island and its largest renewable power plant. It produced nearly one-third of the island’s electricity in 2017. The plant voluntarily ceased operations ahead of the approaching lava flow.
Continuing eruptions have damaged transmission lines and equipment, and local residences are experiencing extended power outages. The island’s utility, Hawaii Electric Light Co (HELCO), has implemented switching operations to reroute power from its nearby plants to customers in undamaged areas of lower Puna.
PGV is a geothermal plant drawing steam and hot geothermal fluid up through 11 wells drilled 6,000’ to 8,000’ deep. Pressurized steam from the hot fluid, along with non-condensable gases, is routed through the facility to drive a turbine generator for producing electricity. Exhaust steam from the turbine is used to vaporize a working fluid which drives a second turbine that generates additional electricity. The remaining steam (along with geothermal fluid) is re-injected into the ground through wells.
Plant operators quenched 10 of the 11 wells to prevent the release of gases. Quenching involves injecting the well with water to cool and depressurize it. The 11th well was plugged with bentonite clay after quenching efforts were unsuccessful. Lava covered two of the capped geothermal wells from the Kilauea fissures in late May. The lava flows also destroyed a warehouse and transmission substation.
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