Siemens Energy to supply hybrid drive system

The NEC project will be the first LNG facility in the world to feature a system of this type, which offers a significant advance in efficiency no matter the weather or temperature. Photo: Adobe

Northeast Energy Center (NEC) and Chart Energy & Chemicals selected Siemens Energy to supply a gas/electric hybrid drive system for NEC’s LNG plant being built in Charlton, Massachusetts.

The NEC project will be the first LNG facility in the world to feature a system of this type, which offers a significant advance in efficiency no matter the weather or temperature. Siemens Energy will serve as the single-source supplier of the integrated drive, providing all rotating equipment and associated control systems, the companies announced.

The hybrid drive system will combine a Siemens Energy low-emissions industrial gas turbine, integrally geared compressor, and electric motor-generator to ensure stable and efficient operation of the plant’s main refrigeration/liquefaction train throughout the year while slashing emissions, reducing costs, and increasing efficiency.

Available power from gas turbines decreases as the ambient temperature increases. As a result, units installed at industrial facilities are often oversized to ensure sufficient power during the hot and humid weather. However, the same gas turbine may generate much more power during cold time than is required, leading to reduced efficiency and increased emissions.

The hybrid drive refrigeration compressor system being supplied for NEC offers a solution to this problem by combining an electric motor-generator with a gas turbine that features a dry-low emissions (DLE) design with lowest achievable NOx emissions levels.

The same system allows NEC an active and powerful tool in demand side management and reduces its costs and the need to purchase power from the grid, while allowing the sale of power back to the utility. The NEC project is strategically important to the security of energy supply of New England that depends on imported LNG.

The NEC facility is expected to produce a baseload of 170,000 gallons of LNG per day for Boston Gas under a firm contract and up to 250,000 gallons per day to other utilities. The gas turbine’s output will decrease when LNG production increases to 250,000 gallons per day on hot summer days when the motor-generator will function as a motor to supply additional power to the compression system.

“The reality is when it comes to facilitating the energy transition, natural gas can be a solution,” said Rich Voorberg, president of Siemens Energy North America. “It will serve as a reliable complement to renewable energy in many regions of the world.”

The combination of the gas turbine, integrally geared compressor, and motor-generator at the NEC plant represents a flexible solution that will enable the liquefaction plant to operate efficiently year-round, he said, adding that the efficiency will reduce energy consumption over the plant’s life.

“The integrated hybrid drive solution provided by Siemens Energy demonstrates the next step in hybridization of the energy systems in their decarbonization process,” said Boris Brevnov, manager and developer of NEC. “Building on this next generation design and its environmental advantages, NEC also offers local utilities a choice of L-RNG, an LNG product made from renewable natural gas.”

The plant has an onsite LNG storage capacity of 2 million gallons. The LNG produced will be available for delivery by truck and used as a feedstock for utility distribution companies and power generation facilities, Siemens Energy said.