Waiau Repower - Project Summary

Waiau Repower

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Project Summary

Proposer Name: Hawaiian Electric Company, Inc.
Parent Company: Hawaiian Electric Industries, Inc.
Project Name: Waiau Repower
Facility Location: 475 Kamehameha Highway, Pearl City, HI 96782
TMK of Facility Location: (1) 9-8-003:010 and (1) 9-8-004:003
Net Nameplate Capacity: 252.8 MW Net
Installed Nameplate Capacity: 261.6 MW Gross
Interconnection Point: Waiau 138kV and Waiau 46kV Substations

Project Description

Hawaiian Electric’s proposed concept to repower the existing Waiau Power Plant in Pearl City is an important step in the transformation of the company’s generation infrastructure and supports the critical need for firm, reliable power that can be quickly dispatched when variable renewable resources such as solar and wind aren’t available.

By replacing six aging, fossil-fueled steam generators with six modern, smaller, more efficient and fuel-flexible combustion turbine units that run cleaner, quieter and fewer hours than the technology it replaces, Hawaiian Electric will enable more renewable energy onto the Oahu electric grid, help reduce carbon emissions and contribute to Hawaii’s 100% renewable energy goal.

The proposed project also will leverage the current land footprint and reuse much of the existing infrastructure, which ensures no new land development and minimizes community impact. The retention and upgrade of Waiau Power Plant with modern units also will provide continued employment for full-time, on and off-site employees, and create opportunities for hiring additional local labor during the project construction.


Project Site Map

The map below shows the location of the Waiau Power Plant on Oahu (upper right corner) and within the geographic area of Pearl City off Kamehameha Highway in an industrial zone area.

Project Site Map

Site Layout Plan

The map below identifies the future location of the new units, left to right:

  • Units 3 and 4 will be replaced by Units 11 & 12
  • Units 5 and 6 will be replaced by Units 13 & 14
  • Units 8 and 7 will be replaced by Units 15 & 16
Site Layout Plan

Interconnection Route

The interconnection route for all units is within the Waiau Power Plant property. Units 11 & 12 will connect to the new 46 kV gas-insulated substation via underground conduit. Units 13 through 16 will utilize the existing overhead structures currently in place for units 5 through 8 to connect into the 138kV switchyard.

Interconnection Route Map

Environmental Compliance and Permitting Plan

Overall Land Use and Environmental Permits and Approvals Strategy

The overall strategy for obtaining required permitting approvals in a timely and cost-efficient manner is based on siting the equipment and proposed facilities on company-owned land and within structures where existing approvals can be leveraged. Additionally, the strategy includes early interface with permitting authorities to understand and address any concerns as well as reviewing available reports and studies containing relevant information about the proposed site. As needed, site visits will be conducted to confirm conditions have not changed since earlier studies or databases were prepared.

Waiau Power Plant is the site of one of Oahu’s largest generating facilities and already zoned for heavy industrial use. Laying out the new units within existing structures is intended to minimize ground disturbance and the need for new construction. The facilities also will be located near to auxiliary resources and infrastructure (e.g., fuel storage and switchyard) already present, and sited outside of the tsunami evacuation zone and sea level rise exposure area.

For further details, please refer to the Environmental Compliance Plan, Chapter 2: Overall Land Use and Environmental Permits and Approvals Strategy.

Please note the plan is dated April 2023 and any changes made by the Development Team since that time may not be on the website immediately until the PUC application for project approval is filed around February 2024.

Gantt Format Schedule

Please note the timing for Waiau 3 & 4 retirement shown in the schedule is dependent on Docket 2023-0339.

City Zoning and Land Use Classification

Under Chapter 205 of the Hawaii Revised Statutes, which establishes state land use law, Waiau Power Plant is located within the State Urban Land Use District.

Under the City & County of Honolulu Land Use Ordinance, Waiau Power Plant is located on land zoned “I-2” or Intensive Industrial District. This zone is appropriate for the proposed project and no changes to zoning are necessary. The location of the proposed project within Waiau Power Plant meets all applicable development standards and a minor modification to the Conditional Use Permit for the facility is required.

For further details, please refer to the Environmental Compliance Plan, Chapter 3: County Zoning and State Land Use Classification.

Land Use, Environmental Permits and Construction Permits and Approvals

Below is a summary of the required permits that may be needed for the proposed Waiau Repowering project and the agency that grants approval. Items with an *asterisk indicate potential opportunities for the public to comment on the project in accordance with the process for the specific permit. For the SMA, the Honolulu City Council also must pass a resolution.

For further details, please refer to the Environmental Compliance Plan, Chapter 4: Land Use, Environmental and Construction Permits and Approvals.

List of Permits and Approvals

Required Permit(s) Agency/Authority
EA or EIS* (as needed) City & County of Honolulu, Department of Planning and Permitting
Special Management Area Permit – Major* (as needed) City & County of Honolulu, Department of Planning and Permitting, and Honolulu City Council
National Pollutant Discharge and Elimination Systems (NPDES) Permit* State of Hawaii Department of Health, Clean Water Branch
Minor modification to Conditional Use Permit City & County of Honolulu, Department of Planning and Permitting
HRS Chapter 6E Historic Preservation State of Hawaii, Department of Land and Natural Resources, State Historic Preservation Division
Significant modification to Covered Source Permit* State of Hawaii Department of Health Clean Air Branch, and U.S. Environmental Protection Agency Region IX
Building, stockpiling or grading permits City & County of Honolulu, Department of Planning and Permitting

Preliminary Environmental Assessment of the Site

Data from past reports and publicly available environmental databases indicates there should be minimal environmental impacts from the development of the Waiau Repower project within the existing footprint of the power plant. For more details, please refer to the Environmental Compliance Plan, Chapter 5: Preliminary Environmental Assessment of the Site.

Below is a summary of potential environmental effects:

The region is considered an attainment area with good air quality. The project will contribute to significant reductions of power generation emissions such as sulfur dioxide, nitrous oxide and greenhouse gas by the replacement of older fossil-fueled units with modern technology that will run cleaner, quieter and fewer hours.

The landscaping/vegetation is minimal within the facility’s footprint to reduce wildfire risk, and ground cover is mainly pavement and gravel. No endangered or threatened plant species are present in the area where the new units will be installed, and no significant adverse impacts on flora or fauna are anticipated as a result of the project.

The project does not have the potential to alter regional airflow substantially and will not significantly increase the thermal signature of the area. The year-round temperate climate in Hawaii is due to its location in the Pacific and the island’s terrain influences rainfall. Northeasterly trade winds dominate in the project area. Wind gusts are moderate except when hurricanes pass nearby.

Most of the Waiau Power Plant facility is built on select fill placed at the site as part of its original development, and the naturally occurring soils in the area have been almost entirely capped or removed. Best management practices will be employed during construction and post-construction to reduce the already low potential for erosion and windborne dust, and to minimize the potential for project-related impacts to soil.

No significant impacts to topography or geography are anticipated. The topography of the project site already has undergone alteration during its long historical use as a power plant. The threat of volcanic activity to adversely affect the site is low and due to the project design requirements, there is no undue risk of failure caused by earthquakes.

The project site will not result in a change in the percent of impervious ground cover at Waiau Power Plant and does not have the potential to contribute additional storm water runoff.

The Waiau Power Plant is located in Flood Zone D, a rating which implies an area with minimal flood risk. Tsunamis pose a risk to many coastal areas on Oahu, however, due to its location along the protected estuarine coastline of East Loch, it is not a substantial risk to the Waiau Power Plant.

H-1 Freeway and Kamehameha Highway along with the generation-related equipment are two sources of noise in the project area. Construction activities associated with the project, such as backup alarms from trucks carrying equipment, may increase noise beyond the property line and require a construction noise permit. The permit will restrict excessive noise during nights, Sundays and holidays.

Roadway service levels and traffic will not be significantly affected by the project as oversized loads, fuel and other deliveries will be scheduled during off-peak hours to the extent possible. While moving oversized loads from the port of delivery to the project site may cause local traffic congestion, they will not be frequent, and the impacts will be temporary.

The project is intended to provide firm reliable power to Oahu homes and businesses, and will not increase the use of potable water or otherwise affect water facilities on the island. The facilities will use Hawaiian Electric’s own telecommunications network and would not burden the island’s existing network.

Waiau Power Plant is in use for electrical power generation and will continue to be used for that purpose once the proposed project is implemented. Aside from the temporary construction employment and expenditures, the project will not stimulate or promote population growth or economic activity. Therefore the project is not anticipated to have a significant effect on the socio-economic environment of the area.

Most of the new equipment and ancillary facilities would be installed inside existing buildings and enclosures, minimizing any change to the visual impact. However, current plans call for the addition of six, new stacks at the same height of the existing six stacks, which would remain in place. Consideration will be given to reduce or remove the existing stacks.

The disassembly and removal of the existing boilers and steam turbines will likely result in large quantities of recyclable material that would be transported to an offsite recycler and will not have a significant impact on solid waste collection activities or landfills. Day-to-day operation of the facility will not produce large volumes or unusual types of solid waste. All wastes generated will be collected and properly disposed.

Hawaiian Electric uses best management practices to handle or store hazardous materials, e.g., solvents, at the Waiau Power Plant. Although some work may involve minor quantities of hazardous materials, the proposed project will not result in the use or storage of a hazardous material not currently utilized at the generating station.

The proposed project does not represent a substantial change from its existing use of water from Pearl Harbor. Additionally, the project will not impact groundwater use, quality or recharge.

Best management practices will be employed during disassembly and construction of the proposed project to minimize or eliminate the potential for substantial impacts to water quality because of wind- or storm-borne particulates, chemicals or other matter entering surface water bodies in the vicinity.

Hawaiian Electric would modify its existing National Pollutant Discharge and Elimination System permit and continue to comply with the conditions of the permit which minimizes the potential for adverse impacts to water quality.

Fire protection is a fundamental aspect of the proposed project’s design, which will comply with the National Fire Protection Association’s recommendations, the Uniform Fire Code, local codes and other applicable fire protection regulations. Frequent fire inspections, site security, vegetation management and other safety protocols will further reduce fire risk.

The proposed project will be located in a fully secured area behind fencing and locked gates. Their presence will not impose a measurable burden on Honolulu Police Department’s Pearl City District 3. The site will be monitored by Hawaiian Electric which will dispatch security personnel if needed to investigate suspicious activity.

The proposed project does not pose a significant health risk. If needed, injured personnel can receive emergency medical attention at several nearby facilities, including Straub Pearlridge Clinic, Queen’s Medical Center West Oahu and Adventist Health Castle Urgent Care Pearl City.

The proposed project is not expected to have impact on local or regional recreation sources including the Pearl Harbor Historic Trail – a section which runs behind the Waiau Power Plant – or the Neal S. Blaisdell Park located nearby. The PHHT would continue to serve as a public recreational resource for bikers, walkers, joggers, birdwatchers, schoolchildren, and seniors as the proposed project will not require any new uses on the PHHT.

The proposed project is intended to create new, reliable, dispatchable generation capacity at Waiau Power Plant. By facilitating the decommissioning and removal of the existing aged units, the project will also provide a secondary benefit of allowing Hawaiian Electric to expand the proportion of renewable intermittent resources such as wind and solar in its total generation portfolio. In addition, the transition to combustion turbines also supports Hawaiian Electric’s goal of decarbonizing its generation fleet through retirements of fossil fueled units.


Cultural Resource Impacts

The proposed project will be developed within the Waiau Power Plant. The site has been used almost exclusively by Hawaiian Electric for electrical generation since its initial construction in the 1930s.

While the broader Waiau and ‘Ewa area has a rich cultural history and recent efforts have been made to restore fishponds and native plants around Pearl Harbor, outside of the property, research indicates that the proposed project is not anticipated to have the potential to adversely affect cultural resources, practices, or beliefs associated with the proposed project area. For further details, please refer to the Environmental Compliance Plan, Chapter 6, Cultural Resource Impacts.

There also may be opportunities to cultivate Native Hawaiian narratives of the region for future generations to enjoy. See the Community Outreach section which also mentions efforts to support organizations working on a native plant garden along the harbor shoreline.


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