The U.S. Army Garrison-Hawaii on Oct. 30 issued a final environmental impact statement finding little in the way of environmental consequences for a 50-MW facility called the Schofield Generating Station Project.
This facility would be located at Schofield Barracks, Wheeler Army Airfield, Field Station Kunia on the island of Oahu. The final EIS was prepared with the help of parties like Hawaiian Electric and consultant Tetra Tech Inc.
The EIS identifies, evaluates, and documents the effects of the Army’s granting of a lease on Schofield Barracks, and the granting of easements by the Army and the State of Hawaii Department of Land and Natural Resources to Hawaiian Electric for the construction and operation of a mult-ifuel-capable 50-MW plant and associated transmission line. That project is the Army’s Preferred Alternative under the final EIS. “Implementation of the Preferred Alternative would result in short- and long-term direct and indirect beneficial and adverse effects,” said the final EIS. “All adverse effects would be less than significant. Cumulative impacts would be less than significant.”
The Proposed Action, referred to as the Schofield Generating Station Project (SGSP), consists of:
- the Army’s lease of 8.13 acres of land and the related granting of a 2.5-acre interconnection easement on Schofield Barracks and Wheeler Army Airfield to Hawaiian Electric to construct, operate, and maintain a 50-MW plant to include associated power poles, high-tension power lines, and related equipment and facilities;
- the Hawaii Department of Land and Natural Resources grant of a 1.28-acre easement and a 0.7-acre conservation district authorization to Hawaiian Electric, allowing for the construction of a 46-kV transmission line between the SGSP site and the existing Wahiawa Substation;
- Hawaiian Electric’s construction, ownership, operation, and maintenance of a 50-MW, biofuel-capable plant and 46-kV subtransmission line required to connect the Schofield Generating Station to the Hawaiian Electric grid.
The proposed facilities would be constructed and operated in accordance with all applicable laws and with approval of the Hawaii Public Utilities Commission (PUC). The electricity produced would normally supply power to all Hawaiian Electric customers through the islandwide electrical grid. During outages that meet the criteria specified in the operating agreement, SGSP output would first be provided to Army facilities at Schofield Barracks, Wheeler Army Airfield, and Field Station Kunia up to their peak demand of 32 MW, to meet their missions, and would additionally support the grid up to its full capacity. If there was a full island outage, the plant could be used to blackstart other plants on the island.
Hawaiian Electric has several objectives that would be met with this project, including:
- Provide 50 MW of new, easily dispatchable capacity to support the Oahu grid, which will contribute to Hawaiian Electric’s ability to deactivate older, less efficient generating units;
- Add a fleet of modern, efficient generating units that can use multiple fuels, including biofuel, and facilitate integration of additional renewable resources that will contribute to meeting or exceeding the state Renewable Portfolio Standard (RPS);
- Provide a quick-starting, high ramp rate facility to help maintain grid stability and support the increasing penetration of variable and distributed sources of power generation, such as wind and solar, on the Hawaiian Electric grid;
- Have a power generation facility at elevation and away from coastlines, which contributes to continuity of electrical power in the event of natural disaster;
- Provide reliable backup power to Wheeler Army Airfield to enhance military, National Guard, and civilian disaster response capabilities; and
- Locate a generation facility on a military installation to contribute to energy security for Hawaiian Electric customers if there is a man-made threat.
The Schofield Generating Station would consist of six Wartsila 20V34DF (or similar) multi-fuel-capable, reciprocating internal combustion engine-generator sets and associated equipment. Each engine would be equipped with selective catalytic reduction (SCR) equipment containing catalysts to reduce nitrogen oxide (NOx) emissions, and an oxidation catalyst to reduce carbon monoxide (CO) emissions. The new facility would provide a total gross generation rating of 50 MW.
Auxiliary equipment would include inlet air filters, gas exhaust silencers and stacks, a closed-loop air cooled radiator array, generator step-up and auxiliary transformers, fuel and lubricating oil handling equipment and associated storage tanks, a water purification system, a urea mixing system to supply the SCR emissions control system, a switchyard, and a facility to receive and regasify liquefied natural gas (LNG).
The generator sets would be installed in a single engine hall. Each generator set would generate approximately 8.4 MW gross. Each of the six engine-generator sets is expected to have an overall annual availability (i.e., operability rate) of more than 95%, including scheduled and forced outages. Each engine is designed to start and be fully operational in 6 minutes or less. Each engine is to provide various ancillary services, such as ramp up, ramp down, spinning reserve, and voltage and frequency regulation, allowing these units to readily adapt to changing conditions that might arise with large amounts of as-available generation on the grid. The engines can operate at partial load, with a minimum load of 50%. Because each engine can operate independently, this gives the 50-MW plant a minimum load of approximately 4.2 MW.