Siemens Drive Technologies Division is providing variable-frequency drives (VFDs) for a $450 million cellulosic ethanol plant under construction by a U.S. subsidiary of Abengoa, a developer of renewable energy solutions based in Seville, Spain.

The energy self-sufficient plant, located in Hugoton, Kan., will be one of the world’s first commercial-scale cellulosic ethanol facilities. Already under construction, the facility will have the capacity to produce 22 million gallons of cellulosic ethanol annually from agricultural residues, prairie grasses and other similar plant material waste products. It is scheduled for commissioning near the end of 2013.

Siemens will provide five Robicon Perfect Harmony drives, including one Gen IV 2,500 hp, one Gen IV 1,250 hp and three GenIII 600 hp medium-voltage drives. The drives will support the plant’s induced-draft fans, forced-draft fans and digester feed screws.

Each of the Siemens VFDs uses a series of low-voltage cells linked together and scaled precisely for a range of voltage and output power. The cell bypass ensures automatic bypass of a failed power cell in less than 500 msec. Instead of shutting down the entire drive, a process-tolerant protection system provides a hierarchical system of warnings.