GEOTHERMAL
What is geothermal?
Geothermal energy comes from heat inside the Earth and can produce electricity used for heating and cooling purposes. It is particularly prevalent in Hawai‘i’s young islands. Geothermal energy can be generated anywhere there is adequate subsurface heat with underlying geology that allows for “optimum geothermal play” or a geological setting that includes a heat source, a migration pathway, a heat reservoir, and potential for economic recovery.
Geothermal is a firm, dispatchable, low-carbon energy resource. Geothermal sources may be accessed through wells that tap into steam, hot water, or geothermal fluid that when brought to the surface can be used to turn turbines, which in turn drive generators to create electricity.
The Kilauea East Rift Zone, thus far the only region developed for geothermal energy in Hawai‘i, has all the attributes necessary for energy generation. Hawai‘i’s only currently operating geothermal facility, the 38-megawatt Puna Geothermal Venture (PGV) power plant is located in this region.
Other areas in Hawai‘i have been studied and show suitable attributes for geothermal energy generation. In general, the probability of accessible geothermal heat decreases as you move up the island chain to the older islands; however, certain areas on these islands, including Oʻahu, where energy demand is high, exhibit geothermal resource probabilities that may make it plausible for electricity generation. Probabilities are believed to be higher in areas of rejuvenated volcanism, such as areas on the south flank of the Koʻolau mountain range (Ito, et al., 2017).
Click below to view a map of geothermal projects in Hawaii. Disclaimer applies.
Please view map in a bigger screen.
Understanding Geothermal as a Public Trust Resource
A “public trust resource” refers to natural resources such as land, water, minerals, and wildlife that are held in trust by the government for the benefit of all citizens. In Hawaiʻi, the Public Trust Doctrine is enshrined in the state constitution and law.
Hawaiʻi’s Public Trust Doctrine is broad, extending to various natural resources beyond water, including land, air, minerals, natural beauty, and Native Hawaiian cultural practices. Article XI, Section 1 of the Hawaiʻi Constitution explicitly states “For the benefit of present and future generations, the State and its political subdivisions shall conserve and protect Hawaii’s natural beauty and natural resources, including land, water, air, minerals and energy sources, and shall promote the development and utilization of these resources in a manner consistent with their conservation and in furtherance of the self-sufficiency of the State. All public natural resources are held in trust by the State for the benefit of the people.”
This doctrine mandates that the state protect public natural resources, ensuring they are managed for the benefit of the public while also considering the traditional and customary rights of Native Hawaiians. The doctrine recognizes both the public’s right to use trust resources and the private, traditional, and customary rights that may exist in those resources. However, the balancing process starts with a presumption in favor of public use, access, and enjoyment. The doctrine ultimately requires a balancing act between protecting natural resources and allowing for their maximum beneficial use, recognizing that these obligations are not necessarily mutually exclusive.
All the Hawaiian Islands possess geothermal energy potential. Currently, the Kīlauea East Rift Zone is the only area in Hawaiʻi developed for geothermal energy extraction.
Geothermal Energy Resource Studies
Used with permission. Image sources: Lautze, N., Thomas, D., Waller, D., Frazer, N., Hinz, N., & Apuzen-Ito, G. (2017). Play fairway analysis of geothermal resources across the state of Hawai‘i: 3. Use of development viability criterion to prioritize future exploration targets. Geothermics, 70, 406-413. The probabilities of a geothermal resource are colored. The map shows probability, but not certainty. Geothermal wells are needed to provide certainty. Areas with restricted land access are shown in striped and crosshatch patterns (e.g., National Park lands, protective conservation districts, and urban areas). Red boxes outline areas proposed for the Phase 2 study. White triangles indicate the calderas of the main shield volcanoes. White stars mark the locations of the Saddle Road well and Puna Geothermal Venture (PGV).
Lautze, N., Thomas, D., Waller, D., Frazer, N., Hinz, N., & Apuzen-Ito, G. (2017). Play fairway analysis of geothermal resources across the state of Hawai‘i: 3. Use of development viability criterion to prioritize future exploration targets. Geothermics, 70, 406-413.