Transformer: The transformer steps the electricity produced by the gas turbine/generators up from 18,000 volts to 115,000 volts to minimize losses in transmission to homes and businesses across the North Shore.
Gas Metering Station: Salem Harbor Station connects into the interstate gas transmission system through the Salem Lateral, a purpose-built pipe that was constructed through two directional drills: one underneath Collins Cove and the second from Bridge Street Point to the Hubline pipeline in Beverly Harbor. The Hubline connects the northern end of the New England gas system to the southern end of the system. The quantity of gas entering the plant is measured at the Gas Metering Station.
Sound Barrier: The transformer is shielded on two sides by sound walls to reduce the sound impacts on the neighborhood. The new SHS has many innovative sound reduction features, including a first-of-its-kind plenum over the gas turbine intake that we have dubbed a “Whipple Box” after the Footprint-employed engineer that invented it.
Heat Recovery Steam Generator: To further increase the efficiency of the facility, the waste heat from the gas turbines is used to heat up water in the Heat Recovery Steam Generator, turning it in to steam that runs the two steam turbines. By recovering and reusing what would otherwise be waste energy, the new SHS can achieve an efficiency of nearly 60% in converting the energy in the fuel to electrical energy.
Administration Building: The administration building contains offices and warehouse space for plant operations staff. Designed to meet LEED Platinum criteria.
Gas Turbine / Generator: The new SHS utilizes two GE state-of-the-art 7F.05 gas turbine/generator sets. These units provide unprecedented efficiency and flexibility, including the ability to provide half of the total output of the plant in just 15 minutes from the time they are called.
Demineralized Water Tank: The demineralized water tank stores the water needed for production of steam in the Heat Recovery Steam Generator. All impurities need to be removed from the water before it can be used in steam production to reduce corrosion and blockages in the miles of pipe used in the facility.
Operations Building: The operations building of SHS contains the monitoring and control equipment for the facility and will be manned 24 hours a day, 7 days a week to ensure that the facility is ready for operations at any time. The core mission of SHS remains the same as it has since the original units were built in the 1950s – to safely and reliably provide electrical power to the residents and businesses of the North Shore.
Ammonia Tank: Nitrogen Oxides (NOx) are a major contributor to ground-level Ozone and are a by-product of combusting natural gas and other fuels. To reduce these emissions to a bare minimum, the new SHS uses ammonia with a catalyst to produce harmless diatomic Nitrogen (N2) and water (H2O). The ammonia used on site is aqueous ammonia – diluted to 19% in solution with water – and is stored in a specially-built tank to eliminate vapor.
2 Steam Turbine / Generators: The GE-made steam turbine/generators use steam produced in the heat recovery steam generators from gas turbine exhaust waste heat to produce additional electricity. Sometimes plants like SHS use only one steam turbine for two or more gas turbines. In order to maximize the reliability of SHS, however, Footprint has opted to use one steam turbine for each gas turbine, allowing either unit to be used completely independently of the other in an emergency.
Air-Cooled Condenser: After pulling the last bits of motive power out of the steam in the steam turbines, the SHS directs it in to the air-cooled condenser where it is cooled back to water for reuse in the Heat Recovery Steam Generator. By utilizing this closed-cooling cycle, the SHS is able to significantly reduce water use. Whereas the four old units of SHS used nearly 600 million gallons of seawater a day, the new SHS uses no seawater and fewer than 120,000 gallons of potable water daily.
Wharf: The site of Salem Harbor Station has had a working wharf for hundreds of years. The current wharf was used for bringing coal and oil to the site during the years the original four units of Salem Harbor Station. Currently, the wharf is being used to bring equipment and building materials for the construction of the new Salem Harbor Station and to remove demolition materials via barge, with the occasional cruise ship paying a visit. When the construction is done, it will be available for cruise ships and other commercial vessels.
Berm: The new SHS is surrounded on three sides by an earthen berm, the interior of which is supported by 25-foot tall gabion walls. The berm has four functions: first, it reduces sound impacts from the plant on the surrounding neighborhood; second, it provides a security barrier around the facility, preventing unauthorized entry; third, it provides a visual barrier of landscaping between the plant and our neighbors; and finally, it maximizes the space available to our neighbors and visitors to access the site.