Geothermal Development

Geothermal drilling and development activities in the State of Hawai‘i have comprised the following (also see Table 1.1).


Hawai‘i Thermal Power Company, associated with Magma Power Company, drilled four shallow wells in the KERZ, very close to the lava fissure vents that erupted in 1955, near the town of Pahoa (Figure 1.12) (Patterson et al., 1994b; Gill, 2011). These holes (TH-1, TH-2, TH‑3, and TH-4) were drilled with a cable tool rig, and they ranged in total depth (TD) from 216 to 689 feet. They encountered temperatures ranging from 109° to 203°F (43° to 95°C) and found some hot groundwater. None were judged to be of commercial interest and all were abandoned.

The National Science Foundation (NSF) funded a geothermal research program headed by the Colorado School of Mines (Keller, 1974). A well was drilled near the summit of Kilauea Volcano to a depth of 4,140 feet to obtain subsurface data on the volcano, as well as to determine the nature of any geothermal resource present. The well was located inside Hawai‘i Volcanoes National Park, and it was therefore never used for commercial applications.

1975 – 1976
Following an extensive geophysical survey of the lower KERZ, the University of Hawai‘i utilized federal, state, and county funds to drill the resource discovery well HGP-A well just south of Puu Honuaula, the initial vent site of the 1955 eruption. HGP-A was drilled with a rotary rig, and it was completed in 1976 at a depth of 6,450 feet. It recorded a maximum temperature of 676°F (358°C) and a total mass flow of approximately 100,000 pounds per hour, with nearly equal amounts of both liquid and steam at a surface temperature of 365°F (186°C) (Thomas, 1982; Boyd, 2002). Well HGP-A powered a 2.8-MW demonstration plant from 1981 to 1989 without any significant change in flowing pressure or steam fraction (Patterson et al., 1994b). The plant was shut down in 1989, and the well was subsequently plugged and abandoned (P&A).

1978 – 1979
Privately financed exploration drilling was undertaken by Puu Waawaa Steam Company (STEAMCO) and Geothermal Exploration & Development Company (GEDCO) on the northwestern flanks of Hualalai Volcano on the western side of Hawai‘i (Fowler et al., 1980). Several geophysical anomalies were surveyed in the area, and two exploratory wells were drilled (FNB No. 1 and FNB No. 2; also known as Steamco 1 and Steamco 2). Commercial temperatures for the time were not encountered in either well, and in 1980 both were converted to water wells.

1981 – 1985
Numerous geothermal exploration wells were drilled in the vicinity of HGP-A (Table 1.1).

  • 1981 – 1984
    Barnwell Industries drilled three test wells and a sidetrack: Ashida 1, Lanipuna 1, Lanipuna 1 ST, and Lanipuna 6. None sustained commercial flow levels, but high temperatures were measured in Lanipuna 1 (685°F) and Ashida 1 (550°F).
  • 1981 – 1985
    Thermal Power Company drilled and tested three wells on its Kapoho State (KS) lease. KS-1 and KS-2 were both commercial producers; however, mechanical damage to the wellbores prevented their development, and they were both subsequently plugged and abandoned. KS-1A was initially tested as a commercial producer, but damage to the wellbore prompted its suspension until PGV repaired it and converted it to an injection well during 1991-1992.

Ormat Technologies, Inc. acquired the 500-acre PGV lease located adjacent to the HGP‑A site (see Figure 1.12) (Teplow et al., 2009).

1989 – 1991 
True/Mid-Pacific Geothermal Venture drilled well KA1-1 (also known as TMP-1, KMERZ A-1, or KMERZ-1) in the Wao Kele O Puna Forest. The project location was approximately 8 miles west of PGV and was located within the Kilauea Middle East Rift Zone. The drilling operator on KA1-1 had numerous problems, including stuck pipe, premature liner-hanger setting, stuck casing, shallow lost circulation zones (LCZs), and drill-pipe twist-offs. Despite a sidetrack and three re-drills, no commercial flow was documented from this well (GeothermEx, 2000). The project was also met with considerable public protest. True/Mid-Pacific abandoned its project after state drilling permits were temporarily suspended for both it and PGV following a 1991 blowout at PGV well KS-8 (Smith, 2013).

1990 – 1991 
The State of Hawai‘i undertook the Scientific Observation Hole (SOH) program, which consisted of drilling 3 deep core holes to delineate subsurface temperatures and to determine lithologic and hydrologic properties (GeothermEx, 2000). Two of the SOH wells (SOH-1 and SOH-2) were drilled in the lower KERZ. The third SOH well (SOH-4) was located between PGV and the True/Mid-Pacific well location (see Figure 1.12). These continuously-cored exploratory slim holes ranged in depth from 5,500 to 6,800 feet (Patterson et al., 1994b). The SOH wells helped to prove that favorable high temperatures prevail over a ten-mile interval along the KERZ. (See additional detail about these wells in Section 3.6.1.)

1990 – 1993
PGV drilled KS-3, KS-7 and KS-8. All three wells were potentially commercial producers; however, they all sustained wellbore damage. KS-3 was repaired and converted to an injection well; KS-7 suffered a shallow blowout and was plugged and abandoned; KS-8 suffered a major blowout after encountering unexpectedly high pressures at depths shallower than anticipated. Well KS-8 was eventually repaired, tested, and briefly placed on production with a generating capacity of 10 MW in October-November 1992. The well was then plugged and abandoned in November after the wellhead was observed to have “risen” 21-inches, possibly due to thermal expansion of the casing. An interval of collapsed casing was found between 586 and 600 feet during the abandonment operations.

1992 – 1993
PGV successfully drilled injection well KS-4 and production wells KS-9 and KS‑10.

The 30-MW PGV plant began commercial operations. This plant has remained in operation since, with production and injection make-up wells drilled to maintain capacity over time. It remains the only operating geothermal plant in the State of Hawai‘i. Less information is available in the public domain about later wells drilled by PGV because of the proprietary nature of the data.

The EPA issued a new five-year Underground Injection Control (UIC) permit to PGV, allowing continued use of the three existing injection wells and the drilling of up to seven new injection wells.

Well KS-11 was completed as a production well to a TD of 6,500 feet (Bour and Rickard, 2000).

Well KS-11 was re-drilled and converted to an injection well after the casing was found to be damaged. Well KS-5 was drilled as a production well to supplement production after the original production wellbore of KS-11 was taken out of service.

Three wells were drilled at the PGV project: a production well re-drill (KS-10RD), a new production well (KS-6), and a new injection well (KS-13) (Spielman et al., 2006).

  • KS-10 was plugged back and re-drilled, kicking off at 4,699 feet, for a total of 511 feet of new hole in 19 days. The re-drill was put back on production with a capacity of about 7.5 MW worth of steam.
  • KS-6 was drilled and completed as a production well near the southwestern edge of the project. It was drilled to 6,532 feet in 65 days.
  • KS-13 was drilled toward the northeastern portion of the project to a TD of 8,297 feet in 87 days. The open-hole segment consisted of a 10-9/16-inch hole drilled directionally with mud motor and measurement-while-drilling (MWD) technology to total depth (TD). The well was targeted to cross two eruptive lineaments: the 1955 eruptive fissure and the adjacent cinder‑cone lineament (Figure 1.13) (Teplow et al., 2009). Lost circulation occurred numerous times between 4,990 and 7,188 feet measured depth (MD). High torque occurred at 8,163 feet true vertical depth (TVD) where molten rock of dacitic composition was encountered. The molten rock flowed up the wellbore and was repeatedly re-drilled over a 26-foot interval, producing several kilograms of clear, colorless vitric cuttings at the surface. The molten zone is overlain by an interval of strong greenschist-facies metamorphism in basaltic and dioritic dike rock.

The Puna Borehole Network was established in the lower KERZ to provide detailed seismic data on the Puna geothermal field. This data is being used to identify fault and dike trends and structures at depth in the area, which is of interest both in terms of drilling targets and volcanic hazard monitoring (Kenedi et al., 2010; see also Section 3.6.5).

Well KS-14 was drilled as a production well with 11-¾-inch casing cemented to 4,878 feet (Rickard et al., 2011a). The total depth of the well is not published.

The most recent well at Puna (KS-15) was drilled as a production well, with 11-¾-inch casing cemented to 4,705 feet (Peters et al., 2013). The total depth of the well is not published.


In the KERZ overall, more than two dozen wells have now been drilled and tested, proving the two-phase resource at Puna at temperatures in excess of 680°F in productive intervals (GeothermEx, 1994). Most major productive zones lie between 4,000 and 7,000 feet below the ground surface, although local permeability has been demonstrated as shallow as 1,800 feet (KS-7) and 3,400 feet (KS-8 and KS-9).

Interest in a project at Hualalai on the west side of the Island of Hawai‘i has also been expressed, as it is located closer to the electrical load centers near Kona, although no reported assessment efforts have been conducted since 1986 (see Figure 1.2). The following analysis was made for Hualalai during the field survey conducted in the early 1980s under the state-wide Hawai‘i Geothermal Resources Assessment Program:

“… geologic mapping on the western flank of Hualalai suggests that frequent eruptive activity has occurred during the last 5000 years. Geophysical surveys have identified distinct magnetic, resistivity and self-potential anomalies near the summit of Hualalai, whereas the lower western flank has not shown significant thermal effects. Geochemical data on the lower flanks were similarly unable to identify any obvious thermally induced anomalies. These data suggest that there is a 35-45% probability of a low- to moderate-temperature thermal resource near the summit of Hualalai and a 20‑30% probability of a high-temperature resource in this area. Probabilities for comparable resources existing on the lower flanks are estimated at 15-25 and 5% or less, respectively.” (Thomas, 1986).



Field surveys were conducted on Maui’s Haleakala volcano in the 1980s within the lower portions of the three major rift zones (Northwest, Southwest and East; Figure 1.14) (Thomas, 1986), and the following analysis was made for the Haleakala Southwest Rift Zone (HSWRZ):

“…geologic mapping has determined that several flows on this rift are less than 10,000 years of age and that a few are less than 1000 years old. Preliminary geochemical studies were unable to identify unequivocal evidence of thermal effects on the lower rift zone area, whereas geophysical soundings indicated that thermal ground waters may be present at depths of less than 3 km. The probability for a low- to moderate-temperature resource is estimated to be 30–40%, whereas that for a high-temperature resource is placed at 15–25%.” (Thomas, 1986).

More detailed exploration of the HSWRZ is now underway, at Ormat’s Ulupalakua geothermal project (Figure 1.15). With Lawrence Berkeley National Laboratory and the University of California at Santa Cruz Ormat as partners, Ormat has received a $4.9M Geothermal Technologies Program grant to undertake the development of a 3-D subsurface model of the resource, and to drill and test 2 exploration wells (Ormat, 2011).

The project area is on reserved lands occupied by Ulupalakua Ranch, Inc. (of which Ormat, 2011, notes that it was seeking to lease approximately 8,000 acres of surface rights), and also on an adjacent 800-acre state parcel that is used for grazing and ranching activities by Ulupalakua Ranch (Figure 1.16).

Ormat submitted an application for a geothermal exploration permit and mining lease for the Ulupalakua project in early 2012 (Osher, 2012). The Hawai‘i Board of Land and Natural Resources (BLNR) determined that an Environmental Impact Statement (EIS) was required, and a draft was submitted for public review in February 2012 (DLNR, 2012b). A final EIS was planned to be filed with the Department of Land and Natural Resources (DLNR) in 2014. Additionally, Ormat is seeking to conduct a Cultural Impact Analysis (CIA) on selected activities (ARRA, 2014).



Current geothermal development activity at the level of the SoH has largely been driven by renewed interest in geothermal energy due to past resource assessments and legislation on Renewable Portfolio Standards (RPS):

  • A state-wide geothermal assessment (GeothermEx, 2005) that estimated combined geothermal potential for Hawai‘i and Maui in range of 525 to 1,535 MW (see also Section 1.6).
  • HB 1464 (2009) setting a RPS goal of 40% renewables by 2030.
  • The Hawai‘i Clean Energy Initiative (HCEI) of 2011 setting a RPS target even higher: 70% by 2030.


Table 1.1: Geothermal Wells Drilled in Hawai‘i



Kilauea East Rift Geothermal Area | Open Energy Information


Author: Department of Land and Natural Resources (DLNR)
Contributor: GeothermEx