AFS Trinity Power Corporation has completed its PIER contract No. 500-98-036: Flywheel Energy Storage System. The overall goal of this project was to identify the key performance elements of an advanced flywheel power system that can perform load following for a distributed generation system. The product demonstrated in this contract is a 100 kW flywheel power system that delivers power for 15 seconds. Prototypes of this system have been constructed, and tested. As a result of this effort, the key performance elements were identified and demonstrated. The demonstrated system shows good commercial potential, and AFS Trinity is continuing with additional development work to make the commercial product more responsive to the marketplace. The company is also seeking new equity investment to complete the steps to a full commercial product launch.
During this contract, AFS Trinity also learned much about the commercial application requirements for this product. The project started in 1998 with the goal of producing an energy storage flywheel that could be used with a residential photovoltaic system for load-shifting energy storage. As the project progressed, AFS Trinity and the Commission realized that this market application had a very low probability of commercial success and decided to shift to a more commercially viable application, that of supporting the increased market penetration of distributed generation systems. The project goal was changed to produce a high power, short duration flywheel power system with applications in distributed generation and power management. Development was then completed for this market application and a successful demonstration of AFS Trinity flywheel technology necessary to support this application was completed.
This project addresses two PIER Program objectives:
1. To improve the reliability of California’s electricity system by developing a distributed generation enabling flywheel energy storage system technology that permits distributed generation technologies to be more easily integrated into the utility grid; and
2. To reduce environmental risks from California’s electric system by providing a more environmentally friendly energy storage technology and enabling the increased use of environmentally responsive renewable distributed generation technologies.
The broad goal of this project was to develop and demonstrate an advanced flywheel system for power management and load following. We have succeeded in this, and have proven the feasibility of the AFS Trinity M3AM Flywheel Power System. As a direct result of the lessons learned in executing this contract, the goals have changed over the course of the contract. Where initially the project proposed to demonstrate an “energy wheel” design, under this effort, we came to realize that a “power wheel” is what the commercial market required, and the Commission agreed. The specific characteristics of the system demonstrated in this effort will be discussed in detail in Section 3 of this report.
3.1 PIER Project Background
Trinity Flywheel Power was created when two entrepreneurs negotiated a license agreement with Lawrence Livermore National Laboratory for exclusive rights to produce flywheels under the patents of Richard Post and LLNL. These patents concerned especially the use of the Halbach Array Motor Generator, and the FPS developed under this PIER II contract contains an FMG based on that concept. In 2001 Trinity Flywheel Power merged with American Flywheel Systems to become AFS Trinity Power Corporation.
At the time this contract was granted, Trinity Flywheel Power had assembled prototype flywheel power systems. We had rotors whose inner layers were fiberglass, and whose outer layers were carbon composite. Rotors were suspended on mechanical bearings. Operation was possible only at low speed and low power, and for short periods of time. The limitations of the power electronics and controls were difficult to overcome with the short run times that were possible with the mechanical bearings. While Trinity had planned to build the systems and to outsource the rotor fabrication, we had not planned to design and create our own power electronics, motor drive software, and controls hardware. But shortly after the award of this contract, when it became evident that the third vendor to attempt the task was failing, we made the decision to do these tasks ourselves, and this contract made it possible to successfully plan and execute that control system work. The task took 18 months, and at that point we had a fully functioning breadboard version of the control software, control hardware, and power electronics.
This achievement permitted us to test the rotating hardware at higher speeds, with higher power discharges, and over longer times, than had previously been possible, and we learned that to achieve the maintenance-free life that we sought would require that we successfully transition to active magnetic bearings (AMB).
CONCLUSIONAFS Trinity Power has achieved many technical advances in its flywheel products during the period of this program. These are summarized in section 4.1. The product is now at a stage where it can be brought to market within about one year of receiving significant new investment. It can also be used for further development and research. AFS Trinity, the CEC and the energy industry have learned many valuable lessons from this flywheel development effort that have been presented in prior progress reports and at industry conferences. We have performed the system integration work necessary to build and test complete flywheel power systems. In particular, we have converged on an optimal set of performance targets that meet customer requirements and are feasible for manufacturing