Concepts for Hybrid Electric Motor-Gas Turbine Driven Compressors

The combination of electric motor and gas turbine drivers to power a centrifugal compressor offers opportunities to take advantage of the individual strengths of each drive in a single package. It also creates a few technical challenges. When we talk about hybrid drives, several architectures are feasible, and the choice depends to a large degree on the project objectives. These could include optimizing efficiency, increasing power for specific situations (high ambient temperatures, starting, upset process conditions), the capability to optimize fuel cost by taking advantage of temporary price differences between gas and electricity, or the increase of availability if one fuel source is temporarily unavailable and managing emissions. The large fluctuation in the availability of electricity from renewable sources can create interesting opportunities. The combination of gas turbines and electric drives can lead to trains where one of the drivers can be decoupled, and it can also lead to drives where electricity export is possible. The paper addresses technical challenges, such as torsional train behavior, and the management of the different power sources, and it will describe the preferred train architectures depending on the project objectives.