Orange County Advanced Power Station (OCAPS) is a dual fuel combined-cycle power plant being developed in Texas, the US.
The facility will generate 1,215MW of electricity per year at peak using a combination of natural gas and hydrogen. This is enough to power around 230,000 homes.
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Entergy Texas, a subsidiary of Entergy, is developing the project. In July 2021, the company commenced the process to seek approval for the construction of the OCAPS.
The Public Utility Commission of Texas approved the construction of the plant in November 2022.
Construction works commenced in April 2023 with a groundbreaking ceremony, and the plant is expected to become operational by 2026.
The project’s operational life is estimated to be 30 years.
OCAPS project is also estimated to create nearly $1.8bn in total economic activity in Southeast Texas, creating 7,000 jobs directly and indirectly.
Orange County Advanced Power Station Location
The OCAPS will be located in Orange, Texas, the US, besides Entergy Texas’ Sabine Power Plant. The location will be near Bridge City close to Praxair’s Gulf Coast hydrogen pipeline.
Overall, the construction works are expected to impact an area of about 26.2 acres of land.
OCAPS Infrastructure
The facility will be designed as a low emitting natural gas-fired power generating facility.
The OCAPS generating system includes two natural gas-fired M501JAC combustion turbines in a ‘2 x 1’ combined-cycle configuration. This implies that two gas-fired turbines with an unfired Heat Recovery System Generator (HRSG) will supply a single steam turbine.
The turbines and HRSGs will have selective catalytic reduction (SCR) to minimise nitrogen oxide (NOx) emissions. It will use an oxidation catalyst to reduce carbon monoxide (CO) and volatile organic compound (VOC) emissions.
The facility will also feature four diesel-fired emergency engines. One of the engines will be used to ensure the safe shutdown of the plant when power services from the grid are unavailable; and another as a backup (emergency) firewater pump.
The remaining two engines will be used as fire protection generator engines for the combustion turbines.
The OCAPS will also have an evaporative cooling tower, a natural gas-fired fuel gas water bath heater, two pressurised aqueous ammonia tanks, and ancillary chemical, oil, and diesel tanks.
Operations
The two M501JAC combustion turbines will compress surrounding air and then heat it by using natural gas or a fuel blend comprising up to 30% hydrogen by volume.
The combustion will take place in dry, lean pre-mix design low NOx combustors. The hot exhaust gases in the turbine section blades will drive the shafts to turn the Brayton Cycle electrical generators.
The hot exhaust gases will be tubed to a waste heat recovery steam generator (boiler) to create superheated steam and generate additional electricity in a single steam turbine generator.
A pipeline would be constructed to connect the hydrogen pipeline to the OCAPS.
Entergy plans to store fuel required for project operations in its nearby Spindletop storage facility.
Hydrogen will be mixed with natural gas via a blending module and fed to the turbine combustors.
The OCAPS plant proposes to use up to 30% hydrogen blend and increase this to up to 100% in the long term for power generation.
The combined-cycle turbine power plant will be connected to the grid via existing transmission line and switchyards located at the Sabine power station.
Contractors Involved
A consortium of Mitsubishi Power Americas, Sargent & Lundy and The Industrial Company received the contract to provide engineering, procurement, and construction services for the OCAPS.
Sargent & Lundy was engaged to serve as engineer of record for the plant.
TIC is the constructor of the project and Mitsubishi is providing its hydrogen-capable power train featuring two M501JAC enhanced air-cooled gas turbines, a steam turbine, a heat recovery steam generator, and an advanced control system.
