In 2005, a drill bit at the Puna Geothermal Venture punched into something unexpected: molten magma. It was only the second time in history that a geothermal well had struck liquid rock. The researchers wanted to turn the borehole into an observatory. The volcano, as it turned out, had its own plans. Thirteen years later, during Kilauea's 2018 lower East Rift Zone eruption, lava flows overran the plant's property, burying two production wells and creeping within striking distance of others. The story of PGV is a story about harnessing volcanic energy -- and what happens when the volcano reminds you whose energy it really is.
The Puna Geothermal Venture sits at about 620 feet elevation in the Puna district on the Big Island's east side, directly atop Kilauea's lower East Rift Zone. The first plant opened in 1993 with ten combined-cycle Ormat Energy Converters -- each pairing a steam turbine with a binary turbine. A second plant with two binary-cycle units entered service in 2012. Together, they drew from a network of production and injection wells drilled thousands of feet into volcanic rock. The production wells tapped fluids at approximately 640 degrees Fahrenheit, a mixture of steam and brine forced up by the immense heat below. After generating electricity, the spent brine -- still around 300 degrees -- was reinjected into the earth. Owned by Ormat Technologies since 2004, PGV provided a significant share of Hawaii Island's electricity and represented the state's only geothermal power source.
In May 2018, Kilauea's lower East Rift Zone erupted in the Leilani Estates subdivision, just miles from the PGV facility. New fissures opened in rapid succession, pouring rivers of lava across roads, through neighborhoods, and toward the geothermal plant. Workers raced to quench and cap the wells -- a process that involves pumping cold water down the borehole to cool the formation and then sealing the wellhead. Lava covered at least two production wells, Kapoho State 5 and Kapoho State 6, burying them under hardened rock. A third well, Kapoho State 14, sat in dangerous proximity to the advancing magma. The plant shut down entirely. Officials assured the public that the capped wells posed no explosion risk, but the images were stark: a power plant built to harness volcanic heat, now surrounded by the very force it tapped.
PGV went offline for over two years. In November 2020, the plant resumed operations after drilling new wells and repairing infrastructure. The eruption had destroyed part of the wellfield but not the geothermal resource itself -- the heat beneath Kilauea's rift zone is effectively inexhaustible on human timescales. By 2023, Ormat announced expansion plans for a "Repower Project" to increase capacity, a bet that the same volcanic forces that nearly destroyed the facility remain the Big Island's best shot at clean, baseload electricity. Water wells in the vicinity still register temperatures up to 193 degrees Fahrenheit at depths under 750 feet. The earth here is thin and hot, and the energy is always available -- provided you are willing to share the neighborhood with an active volcano.
The Puna Geothermal Venture is located at 19.48°N, 154.89°W in the Puna district on the Big Island's eastern flank. From the air, the 2018 lava flows are clearly visible as dark, unvegetated channels cutting through the surrounding tropical forest. The plant sits near Leilani Estates. Nearest airport is Hilo International (PHTO), about 20 miles northwest. The contrast between black lava flows and green vegetation makes the eruption zone highly visible at 3,000-6,000 ft AGL.