A company planning to develop a geothermal energy project on the southwestern slope of Haleakala said it hopes to begin drilling exploratory wells as early as next year to determine whether there are sufficient geothermal resources at the site.
Ormat Technologies Inc., which operates the state’s only geothermal plant in the Puna District on Hawaii island, provided a rough outline of its proposed Maui project in an environmental impact statement preparation notice filed with the state earlier this year.
Officials from Nevada-based Ormat said there are still many questions about the characteristics of the project site that will have to be answered before they decide whether to build a geothermal power plant on Maui.
A report done for the state Department of Business, Economic Development and Tourism by a consultant in 2005 concluded that the site had enough theoretical geothermal potential to support a 35-megawatt facility, or enough to power about 23,000 homes.
Ormat will have to drill at least three exploratory wells to be certain a power plant would be viable in the area, said Paul Thomsen, Ormat’s director of policy and business development. Including the time it will take to obtain the necessary state and county permits, it probably will be 12 to 18 months before the wells can be drilled, he said.
Officials from the state Energy Office say geothermal power is a key part of Hawaii’s renewable energy portfolio. The 2005 consultant’s report estimated that there are enough geothermal resources on Hawaii island and Maui to generate more than 1,500 megawatts of electricity, an amount roughly equivalent to the peak electrical load of the entire state.
One of the main advantages of geothermal compared with solar- and wind-generated energy is that the steam from the geothermal wells produces "firm" power similar to that of a traditional oil-fired power plant. Solar power is available only during daylight hours, and even then the electrical output of photovoltaic panels can spike up and down depending on cloud cover. Similarly, the energy produced by a wind turbine can vary depending on wind speed.
Another plus with geothermal is the cost. A state consultant estimates power can be produced in Hawaii at a cost of 7 cents to 8 cents per kilowatt-hour using geothermal. That compares with 21.8 cents per kilowatt-hour that HECO has agreed to pay developers for solar electricity.
However, prospecting for geothermal resources in Hawaii can be costly, with the typical project requiring the drilling of one or more test wells through layers of rock to depths of 6,000 feet or more.
Before Ormat can proceed on Maui it will need to secure geothermal mining leases from the state and an expansion of the existing state geothermal resource subzone. The Maui Planning Commission approved on Feb. 28 permitting rules that will apply to any geothermal developer on Maui.
Ormat also will have to complete a full environmental impact statement for the project. The EIS preparation notice filed on Jan. 26 was the first step in that process.
The EIS preparation notice identified a host of issues that will be addressed by Ormat as it undertakes the full EIS, including risk of earthquakes, potential for lava flows from Haleakala, emissions from geothermal wells and the impact of the project on plants and animals in the area.
The Hawaii chapter of the Sierra Club will be monitoring the project to ensure that environmental laws are followed and to address ways to mitigate potential impacts on the environment, said Robert Harris, group president.
Drilling for geothermal projects can sometimes penetrate underground aquifers, creating the potential for drinking water sources to be contaminated, Harris said.
"A well-done environmental study will look at these kinds of things and make sure the public has all the information it needs," he said.
Harris said government officials must be careful not to weaken regulatory oversight of geothermal projects in an attempt to speed up the transition to renewable energy. The Sierra Club recently testified against two bills introduced at the Legislature this session that would effectively reduce the environmental review required for geothermal projects.
One of the bills, HB2689, would exempt exploratory geothermal wells, also known as "slim wells," from environmental review. The other measure, HB2690, would differentiate between "geothermal resources exploration" and "geothermal resources development" for purposes of mining leases and exploration permits. Exploration would be subject to less stringent environmental review than actual development of projects.
Ormat said the exploration phase of its Maui project will cover 5,315 acres occupied by Ulupalakua Ranch ranging in elevation from 200 feet to 5,400 feet. About 800 acres of the site is owned by the state. The actual footprint of the geothermal power station, if it is built, would be considerably smaller, Thomsen said. A typical 30-megawatt Ormat facility occupies about 5 acres, he said.
Any electricity generated by Ormat on Maui would be sold to Maui Electric Co., which announced last year that it was looking for developers to provide up to 50 megawatts of "firm," renewable power.
Ormat’s 38-megawatt Puna Geothermal Venture facility on Hawaii island provides enough electricity for 25,000 residents and visitors and saves Hawaii Electric Light Co. more than 144,000 barrels of oil a year, according to PGV’s website.
