Steep Terrain Tests Crews at Hawaiian Wind Farm
Built above the town of Maalaea in the West Maui Mountains of Hawaii, Kaheawa II challenged the project team because of the site's steep terrain, high winds and corrosiveness. Still, the wind farm was delivered in October 2012 on schedule and on budget.
Kaheawa II comprises 14 1.5-MW turbines located below Phase 1 and adds 21 MW of power generation for an overall combined capacity of 51 MW. Among the innovations was the use of a battery energy storage system that maximizes wind energy efficiency and helps ensure reliability for Maui Electric Co. customers, says Haile Henry, RMT project manager.
In addition, the project implemented what owner First Wind claims is the state's first habitat conservation plan for a utility-scale wind project. This required replanting indigenous plants and monitoring the nene—a type of goose that is Hawaii's state bird—and the endangered Hawaiian hoary bat.
Kaheawa II was also one of few wind projects nationwide to be built with a foundation mounting piece, which connects the tower foundation and base section, eliminating traditional shims or leveling nuts and anchor bolt tensioning by pouring concrete in situ. The team closely monitored the pours for quality control, carefully adjusting after the initial setting and before grouting, Henry says.
The terrain's challenges limited delivery logistics. Each of the turbine sites was constricted by minimal permitted disturbance areas. That necessitated a daily scheduled just-in-time delivery system for off-loading, cleaning and erecting the components, which were stored almost 10 miles away.
The main access road is approximately four miles long with a varying 16% to 21% grade, taxing mega-equipment such as a 600-ton crawler, 100-ton support crawler cranes and concrete trucks. Track pads were frequently replaced. In March, 25 consecutive high-wind days inspired an extraordinary appeal. Henry says, "A local priest had to come back to the site to do another site blessing in order to appease the local gods to allow us to finish construction."
Kaheawa Wind Project Phase II, Maalaea, Hawaii
Contractor RMT Inc., Madison, Wis.
Owner First Wind, Boston
Lead Designer RMT Inc., Madison, Wis.
Structural Engineer Barr Engineering, Minneapolis
Consultants ECI, Billings, Mont.; Xtreme Power, Kyle, Texas
Subcontractors Reef Development, Puunene, Hawaii; Henkels & McCoy, Kapolei, Hawaii; Goodfellow Bros., Kihei, Hawaii; BanksPacific Construction, Kihei, Hawaii