Sewaren 7 Combined-Cycle Power Plant, Woodbridge, New Jersey, United States of America

Sewaran 7

Sewaren 7 is a combined-cycle power plant being developed in Woodbridge, New Jersey, US. PSEG Power's subsidiary PSEG Fossil is executing the 540MW highly efficient power project, which will produce sufficient electricity for 500,000 homes.

Estimated to cost $600m, the new plant is part of PSEG's plan to replace units 1, 2, 3 and 4 of its existing Sewaren coal-fired power plant located on the same site. The units are being retired after approximately 70 years of operation.

PSEG is investing in the new plant in order to take advantage of lower gas prices, as well as to reduce power plant emissions. Construction of the Sewaren 7 plant commenced in June 2016 and is scheduled to be completed by 2018.

The project is expected to generate significant tax revenue for the local economy and economic benefits during the construction phase by creating 350 jobs. It will also generate another 28 full-time jobs, once operations commence.

Sewaren 7 plant make-up

The new plant will replace the existing less-efficient generating units with a dual-fuel combined-cycle power plant. It will be equipped with GE's 7HA.02 gas turbines and steam turbines housed in a turbine building.

The plant will include a heat recovery steam generator (HRSG), a fuel gas heating station, an air-cooled condenser, an emergency diesel generator, an auxiliary electrical building, a main stack, and an auxiliary boiler stack.

The air-cooled condenser will be 125ft-tall and include 20 discrete heat transfer cells covering 40,500ft². It will continuously recycle water for cooling purposes, thereby reducing the need for cooling water. The condenser will also decrease the plant's dependence on the Arthur Kill tidal strait for cooling water.

Additional facilities include fuel oil forwarding pump house, fuel oil tank, emissions monitoring building, hydrogen and ammonia storage tanks, and fire water storage tanks. The plant will also be equipped with a 230kV step-up transformer, an auxiliary cooling tower, a warehouse, and a service water pump house.

Technology and fuel used at Sewaren 7

The combined-cycle power plant will use gas and steam to generate power from the same amount of fuel. Natural gas will be fired in the gas turbine generator to generate electricity. Waste heat from the gas turbine will be diverted towards the HRSG to produce steam, which will drive the steam turbine to generate additional electricity.

"The project is expected to generate significant tax revenue for the local economy and economic benefits during the construction phase by creating 350 jobs."

The 7HA.02 gas turbines of the plant are highly efficient and can produce the same amount of power from half the quantity of fuel as compared to the older steam generators.

The plant is designed to operate on two types of fuel, including natural gas and ultra-low sulphur distillate (ULSD) fuel oil. The dual-fuel capability will enable the use of ULSD in the event of a shortfall in natural gas supply, increasing the plant's dependability and reliability.

The natural gas required for the plant will be supplied through the Texas Eastern and Transco pipelines.

Emissions control at the combined-cycle power plant

The technology used in the HA gas turbines will reduce the emission rates of the new plant to roughly half as that of the older plant. The emissions reduced by the technology are equivalent to taking more than 150,000 cars off the roads.

The plant will also be equipped with a combination of low nitrogen oxide combustors and a selective catalytic reduction system to reduce nitrogen emissions. An oxidation catalyst will also reduce the carbon monoxide emissions.

Contractors involved

Black & Veatch was awarded the engineering, procurement services and construction management contract for the project.

GE is supplying the gas turbines, while Holtec International is supplying its air-cooled condenser for the plant.

Matrix Service Company was awarded a contract to carry out above-ground electrical construction work in April 2017.

Stonebridge Steel Erection used 1,500t of steel for erecting seven buildings of the plant, including the turbine hall, and fuel and gas building.