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we can build a more precisely regulated DC control circuit. Using a 20 percent platinum black-on-carbon compound and liquid Nafion (known as Liquion), we were able to heat-press a layer and reassemble the stack. Our design is, at best, 50 percent efficient now, but with further redesign, 85 percent may not be an unrealistic goal.

In our system, we stored the hydrogen at fairly low pressures of less than 100 psi, in a 2 cubic foot (0.06 m3) aluminum gas cylinder. Since we are going from a dense liquid to a very light gas it stands to reason that the electrolyzer becomes self-pressurizing when the gases are contained within a closed vessel. One interesting discovery was the fact that the electrolyzer acted as a fuel cell once the power was disconnected. I think a practical, combination fuel cell/electrolyzer is quite possible, but it would require a fair amount of redesign. Additional detailed information on this process is available at Proton Energie's web site at: www.protonenergy.com or Stuart Energy at: www.stuartenergy.com.

Renewable Hydrogen

We pursued this method of hydrogen production in spite of criticism from those who felt it was wasteful to use renewable energy to power the less than 100 percent efficient electrolysis process. Few seem to consider the fact that extraction of fossil fuels, in many cases, uses enormous quantities of fuel just to get it to the end user. There are, in fact, many good arguments for the use of this PV, electrolyzer, hydrogen storage, fuel-cell process.

Electrolyzers that use renewable energy to convert water into hydrogen gas could expand the use of solar and wind power. Both of these sources of energy are highly variable. Sun is available less than half the day, and wind is highly erratic, even in good wind regions.

This means that we now use the grid, lead-acid batteries, or some other means to store this energy. In the case of the grid, it is not truly stored, and the true overall efficiency is rather poor. Lead-acid batteries can never serve as a practical storage medium if off-grid systems become ubiquitous.

I have yet to see a solar or wind system that lacks a voltage regulator. Most of these regulators dump excess energy when the battery is full. Would it not be more efficient to use the wasted energy to electrolyze water?

Water is available universally, worldwide. When 2.3 gallons (9 l) of water is turned to hydrogen, the energy equivalent of one gallon (3.785 l) of gasoline is liberated. Even the most advanced battery system could store only a fraction of this energy when weight and volume are taken into account. When consumed, hydrogen turns back to water, whether burned or run through a fuel cell.

With more research, electrolyzers can reach as high as 85 to 90 percent efficiency. Fuel cells have the potential to reach 75 or 80 percent efficiency. With combined cycle efficiencies of over 60 percent, we exceed the overall efficiency of most fossil fuel extraction and any form of grid power. All of this gives us good reasons to pursue and further promote the electrolysis process.

Our adventure into fuel cell and electrolyzer design and fabrication has been very rewarding. We were able to learn a lot about the electrochemistry involved, in a hands-on manner. It greatly increased our interest in promoting this technology as a practical and ultimately cost-effective addition to the ever-expanding renewable energy inventory. We hope to provide more detailed updates in future issues of Home Power.

Access

Larry Elliott, Ion Technologies, KATTEL, 5808 Burgdorf Rd., Bonanza, OR 97623 • 541-545-3201 Fax: 541-545-6700 • [email protected] www.kattel.orgwww.ionfuelcells.com

Oregon Institute of Technology (OIT), 3201 Campus Dr., Klamath Falls, OR 97601 • 541-885-1000 Fax: 541-885-1865 • [email protected]www.oit.edu

Spectracorp, 599 Canal St., Lawrence, MA 01840 978-682-1232 • Fax: 978-682-3253 • [email protected] www.spectracorp.org • Carbon paper electrode/diffuser

Delker Corp., 14 Commercial St., Branford, CT 06405 203-481-4277 • Fax: 203-488-6902

Hydrogen

[email protected]www.delkergrid.com Nickel screen electrodes

Ion Power, Inc., 102 East Scotland Dr., Bear, DE 19701 877-345-9198 or 302-832-9550 • Fax: 302-832-9551 [email protected]www.ion-power.com PEM membranes and fuel cell components

MSC Corp., 151 Sunnyside Blvd., Plainview, NY 11803 800-645-7270 or 516-812-2000 • Fax: 800-255-5067 or 516-812-1714 • [email protected] www.mscdirect.com • Delrin and raw materials

Rhino Enterprises, 834 Market St., Klamath Falls, OR 97601 • 541-840-4768 • Fax: 541-884-6740 [email protected] • Lab supplies

Maxwell Technologies, 9244 Balboa Ave., San Diego, CA 92123 • 858-503-3300 • Fax: 858-503-3301 [email protected]www.maxwell.com PowerCache capacitors

Alfa Aesar, Johnson Matthey Co., 30 Bond St., Ward Hill, MA 01835 • 800-343-0660 or 978-521-6300 Fax: 978-521-63 50 • [email protected]www.alfa.com Platinum

Christine Parra, Schatz Energy Research Center, Humboldt State University, Arcata, CA 95521

[email protected]

www.humboldt.edu/~serc/index.shtml

Thanks to Christine Parra for technical review of this article.

We would like to thank the American Association of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) for a generous donation of US$7,000, and Bob Rogers, instructor at Oregon Institute of Technology for help in obtaining the grant.

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