World’s first hybrid supercapacitor, flywheels and LAES system to test EFR and FFR capability

World’s first hybrid supercapacitor, flywheels and LAES system to test EFR and FFR capability

World’s first hybrid supercapacitor, flywheels and LAES system to test EFR and FFR capability Energy Storage Journal


Energy storage company Highview will test the grid frequency service capabilities of the world’s first hybrid flywheel, supercapacitor and Liquid Air Energy Storage system at its Viridor’s Pilsworth landfill gas plant in the UK, the firm announced on October 12.

The project at Highview’s existing 5MW/15MWh LAES pre-commercial demonstrator look at how the system can meet the requirements of the UK grid operator National Grid’s Enhanced Frequency Response and Firm Frequency Response services.

The Pilsworth LAES plant will be commissioned in early 2018 and the hybrid system is due to be in full operation by next summer.

The project will use a Siemens supplied flywheel system storing up to 4000kJ, with the 2950kJ supercapacitor coming from Maxwell Technologies. The power conversion element to control the transfer of energy to load banks, supercapacitors, flywheels and the grid will be provided by Siemens Sinamics S120.

Vincent Morton, Siemens’ development manager for integrated drive systems, told ESJB the technologies were chosen over lithium-ion because a flywheel and supercapacitor hybrid system was better suited to the requirements of delivering a large burst of energy for a relatively short time — high power, low energy — that suited the application.

“From calculating many combinations to suit the particular parameter in this system (including but not limited to: energy, power, duty cycle, budget) this system was selected,” Morton said. “The combination of flywheel and supercapacitor also allows flexibility and a platform to innovate and develop advanced control of power management between the different types of storage.”

The LAES process is expected to ramp up to the declared output in a few seconds, with the energy storage system providing the balance of the declared output during this period. The Siemens Sinamics S120 power converters will control the flow of energy in and out of the flywheels by accelerating or decelerating the flywheel rotor.

The S120 motor modules provide a variable voltage, variable frequency three-phase supply to the flywheel stator and converts this to a steady DC voltage on the S120 DC-link. The Sinamics DCP controls the flow of energy in and out of the supercapacitors by increasing/decreasing the DC voltage applied, while maintaining a constant DC voltage at the S120 DC link.

The S120 active front end then converts this DC voltage from the DC link to a 50Hz grid compliant import/export to the grid via a Siemens GEAFOL transformer.

The overall state of charge management of the storage devices and interaction with the Highview LAES will be controlled by a Siemens PCS7 Distributed Control System. Highview is working with a system integrator to develop the algorithms for this.

Matthew Barnett, business development director at Highview said: “This is the world’s first hybridized LAES System that uses the best attributes of established components configured to deliver a smart liquid air battery plant, capable of delivering instantaneous power with long duration at utility scale.

“This will provide valuable services to the grid and contribute to future-proofing our electrical infrastructure.”

Highview was awarded funding of £1.5 million ($2 million) for the project from Innovate UK, the UK’s innovation agency in August, with additional funding of more than £8 million coming from the Department of Business, Energy and Industrial Strategy in 2014.

Highview built the world’s first pilot plant (350kW/2.5MWh) in 2011, which was connected to the grid at UK distribution network operator Scottish and Southern Energy’s biomass plant in Slough until 2014. The hybrid LAES system will be added to the existing pre-commercial demonstration plant at project partner, Viridor’s, Pilsworth landfill gas plant in Bury, Greater Manchester, UK.

On October 19 Highview named Colin Roy as its new executive chairman, taking over from Timothy Barker, who has been chairman for some 10 years.

Roy has been a shareholder in Highview for almost a decade.