Project Spotlight: Kapolei Energy Storage Project

Kapolei Energy Storage (KES)

Kapolei Energy Storage (KES) is located on roughly eight acres of land in Kapolei on the island of O‘ahu, situated in I-2 (Industrial) zoning outside the Tsunami Evacuation Zone – an optimal location for new energy infrastructure.

As a state-of-the-art battery energy storage system, when complete, the KES will store 185 MW / 565 MWh of power harvested from solar, wind and geothermal sources to provide clean power to Hawaiian Electric Company. It will be interconnected at a critical existing Hawaiian Electric substation and is planned to provide about 10 percent of power used during peak evening and overnight hours, providing both power and stability to the Hawaiian Electric grid on O‘ahu.

The project was first approved by the Hawai’i Public Utilities Commission in May of 2021. The KES project received unanimous support from the local Neighborhood Board and approval of its Conditional Use Permit-Minor from the City and County of Honolulu. Construction began in April 2022 and is set to complete in May 2023. The project will help replace power lost from the AES coal-fired plant that closed in September 2022, and will support the state’s goal of shifting from fossil fuels to 100 percent renewable energy generation by 2045.

GBI’s scope of work for the Tesla Megapack 2XL project involved importing 9,200 cubic yards of coral, pouring 44 concrete pads using 2,384 cubic yards of concrete, and preparing the site for the installation of three-megawatt storage batteries. The project tasks also included clearing and grubbing, fabricating, and stripping forms, pouring the concrete foundation, and importing materials. Key challenges encountered during the project were related to curing the concrete, grinding the concrete pads, and coordinating schedules with other subcontractors.

Curing Concrete: Surface cracks emerged as a result of wind and temperature increases, causing difficulties in the concrete curing process. The team overcame these issues by pouring concrete early in the mornings to complete the work before the sun and wind intensified. They also employed curing blankets to mitigate the problems.

Grinding Concrete Pads: The concrete pads needed to be perfectly flat for the batteries, a difficult feat to achieve. To create the required level surface, the team ground down excessively high spots, used shims, and employed a bump cutter to make the pads as flat as possible.

Scheduling with Other Contractors: Electrical lines had to be installed beneath the pads, which necessitated coordination with the electrical subcontractor. GBI’s original schedule and production were based on pouring three pads per day, every other day. However, delays with the electrical contractor required flexibility in the team’s approach. They prepared as many areas as possible to pour concrete in any available space. Effective communication with the electrical subcontractor and general contractor proved crucial in managing these scheduling challenges.

GBI’s involvement in the project came through a long-term relationship with prime general contractor, Moss & Associates. After working with Moss & Associates at the Marine Corps Base Hawaii Housing Project in 2016, GBI was contracted to do the civil work for Moss & Associates’ first three solar farms the following year. GBI is a trusted partner who brings familiarity and consistency to Moss & Associates, applying lessons learned and proactive cost and schedule solutions. Eight projects and seven years later, GBI is still their contractor of choice as together, they tackle the KES project, and another successful renewable energy project.


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Image source: Plus Power


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