High-Pressure Electrolysis Optimized for Supplying Premium Power

from Wind and Photovoltaic Power Sources

Martin A. Shimko, President, mas@avalence.com

Avālence LLC

1240 Oronoque Road

Milford, CT 06460 USA

Phone (203) 701-0052

FAX (203) 878-4123

Electrolysis enables the "distribution" of hydrogen fuel by using either the existing electrical infrastructure (grid) or on-site renewable power sources to produce hydrogen renewable power storage applications (peak shaving, 24/7 availability, and back-up power).  Linking an electrolyzer to renewable power sources can be effectively used to firm the power supply to the grid from these otherwise intermittent power sources and minimize the impact of renewable power resources on the electric grid.  This feature will become critical as renewable sources such as wind try to supply local markets with more than 15 to 20% of the total grid energy.  When linked to a fuel cell or hydrogen driven IC gen set the value of this “dispatchable on-demand” power relative to the raw renewable power results in a compelling value proposition with attractive capital pay back periods and return on investment. The extreme example of premium power “value” is in back-up power applications delivering power to mission critical applications during a power outage.  An integrated fuel cell/storage/electrolyzer unit that can replenish the hydrogen supply following an outage increases this value by obviating refueling visits which can have staggering costs in remote locations. This paper will discuss the value proposition for the full range of these premium power applications.

Avālence LLC is now producing electrolyzers that generate hydrogen fuel directly at pressures up to 6,500 psi, eliminating the need for any type of drier or compressor, while supplying volumetrically efficient hydrogen energy storage.  Avālence is presently teaming with United Technology Corporation Power to demonstrate a self refueling back-up power system operating directly from a photovoltaic array.  The electrolyzer also has the option of operating from a 208V grid power source as needed.  This fully autonomous back-up power system is composed of a 5 kW Pure Cell Fuel Cell from UTC Power, 9 kg of hydrogen storage in nine 6000 psi steel tanks, an Avālence Hydrofiller 15 – 6500 RG electrolyzer, and a 3 kW photovoltaic array.  Field testing of the integrated system is scheduled to begin in December 2007. It should be noted that no power conditioning equipment is required to link the PV array and the electrolyzer. A similar system is shown in the figure.  This paper will report the preliminary results from this testing.

In addition to this hardware demonstration, Avālence has begun a collaborative effort with CAP Energy of Israel to develop power conditioning and control equipment for use on several wind turbine generator designs, enabling direct and efficient linkage to our electrolyzers through a broad range of wind speeds.  The control equipment will be mounted in the electrolyzer and will control the output voltage from the wind turbine generator to match the power/current characteristic of the electrolyzer.  The paper will also report the results of this design work, documenting the projected performance of the system.