Fuel Cells and a Sad Goodbye
Like many of you, I''m in a rather depressed state after not only
paying Uncle Sam his due, but also watching my accumulated
wealth take a nosedive in that horrific market plunge. Although
last week''s column on lunch with The Donald probably seemed
light-hearted, my mood the past month has actually been quite
somber. The reason for this sadness was the sudden and shocking
death of a good colleague and friend, Charles Grun.
On March 13, Charlie completed his usual morning run of several
miles at a local track, got in his car to return home and had a fatal
heart attack. Although a diabetic, Charlie was Mr. Physical
Fitness and, in addition to running, regularly engaged in racquet
ball games with one of our graduate students some 40 years
younger. Not too long ago, grounded by a knee problem, Charlie
underwent surgery and was back in his running shoes in a
remarkably short order. Next to my wife, it was Charlie who for
years has kept prodding me to keep up my daily three-mile walks.
A voracious reader, he also passed along to me his many technical
magazines, sources of many tidbits I''ve used in these columns.
My last contact with Charlie was in February, when he called me
in Marco Island to ask if I needed reading material and to make
sure that I was walking. I had plenty to read and could report a
walk of over six miles on the beach that morning.
In spite of, or perhaps because of his horrible childhood, Charlie
was the most positive individual I''ve ever known. At 10-12 years
old, he was in a line with his parents when they were separated,
Charlie to work in the concentration camps while his parents
presumably perished in the gas chambers. Possibly because of his
surviving the Holocaust, Charlie woke up every morning thinking
it''s great to be alive and filled his day to the fullest with work,
exercise, a thirst for knowledge and family. I had not met his
family until the day of the funeral and was in for a surprise.
Charlie had spoken on occasion about his sons and daughters. I
found that he actually had only daughters and that his "sons" were
really sons-in-law, but were treated by Charlie as his own. This
was my first Jewish funeral service, held the next morning after
his death. I''ve been to services at which the deceased was
extolled to such an extent that you wondered whether this saint
was the person you had known. In Charlie''s case, we all agreed
that every heartfelt word spoken in praise of his virtues was
Before joining our battery group, Charlie had his own little
company making electrodes for metal-air batteries and fuel cells.
It''s fitting that this week''s column should deal with fuel cells.
Today''s gasoline prices have spurred renewed interest in battery-
powered vehicles. Honda and Toyota have been selling in Japan
"hybrid" vehicles powered by combining the battery and internal
combustion engine. Last year, DaimlerChrysler demonstrated its
NECAR 4 auto, powered by a fuel cell. Also, there are buses in
the U.S. and Canada that are running on fuel cells.
What is a fuel cell? In a battery, the amount of electricity we get
out depends on the amounts of active ingredients packed in the
electrodes and, possibly, in the electrolyte of the battery. In a fuel
cell, we also have electrodes and an electrolyte. However,
instead of packaging our active ingredients, we keep feeding these
ingredients into the fuel cell as it''s generating electricity. So, as
long as we keep feeding it, the fuel cell continues to make
electricity. At the same time, so as not to clog up our fuel cell,
we must remove the products of the cell reaction.
What do we feed it? It sounds tricky, especially since the
products of most reactions that occur in practical batteries are
solids. One can imagine having to continuously shovel out this
stuff to make way for the incoming fuel. But suppose we feed the
two electrodes with simply hydrogen and oxygen gases? If you''ve
taken high school chemistry, you''re right. It is just the reverse of
the electrolysis of water. In that experiment, we hooked a battery
to a couple of wires, stuck the wires in water with some acid, and
collected hydrogen and oxygen in our test tubes. And what is the
product in our fuel cell? Of course, it''s the environmentally
"greenest" possible material - water! We don''t even have to
supply pure oxygen, but can just use a fan to blow in air. Oh, by
the way, the other product is electricity.
If we don''t happen to have hydrogen handy, we can "reform"
something like natural gas into a hydrogen-rich feedstock for our
fuel cell. In the greenest of all possible worlds, we might even
use solar energy to generate hydrogen by electrolysis of water.
It sounds like Utopia, doesn''t it? There are a couple things I
didn''t mention. One is that the hydrogen and oxygen don''t just flit
into the fuel cell and neatly react to form water. We need a
catalyst on the electrode surfaces to help them do the right thing.
A catalyst provides a surface that encourages, for example, a
hydrogen molecule to split into two hydrogen atoms. You
remember that a hydrogen atom is just an electron whirling
around a proton. The catalyst may then prod the hydrogen atom
to give up its electron to the electrode, leaving a proton, which is
a hydrogen ion. The hydrogen ion then can travel through the
electrolyte carrying its positive charge, while the electron with its
negative charge goes through the electrode to the outside world
as electricity. The reactions involved in different types of fuel
cells are different but you get the idea. The surface of an ideal
catalyst is unchanged by the whole process and is ready to do the
same for the next hydrogen molecule. Unfortunately, it turns out
that platinum is the best catalyst. As you know if you''ve priced
platinum jewelry, it isn''t cheap! Cost is a problem.
There are a couple more small items. In order to generate the
rather large currents needed to drive a car or generate power for
a building, you need lots of ions in the electrolyte. It also helps
to speed things along by raising the temperature. Now things get
a little dicey. For decades, the fuel cells used on space missions
(e.g., on Apollo 13) have contained strong, corrosive alkaline
electrolytes of potassium hydroxide, almost pure lye. These
alkaline fuel cells operate at roughly 200 degrees Centigrade, well
above the boiling point of water (100 degrees Centigrade).
The alkaline fuel cells seem on their way out. A United
Technologies subsidiary, ONSI, is marketing another type of fuel
cell for larger scale power generation. Instead of an alkaline
electrolyte, this fuel cell employs a phosphoric acid electrolyte,
operates at about the same temperature and uses reformed natural
gas. ONSI has sold over 200 of its 200-250 kilowatt fuel cell
plants worldwide. (For comparison, our home''s electricity
consumption is about 25 kilowatt-hours per day. If my math is
correct, one of these ONSI plants could handle the needs of
roughly 240 such homes.) The niche for these phosphoric acid
fuel cell plants is "distributed power", a buzzword for having your
own on-site (hence, ONSI) power generator. Banks, hospitals,
airline terminals and the like are fuel cell customers worried about
computer glitches and power for emergency situations.
"Cogeneration" is another term you''ll see in connection with fuel
cells. Not only do they operate at high temperatures but the fuel
cells themselves generate a lot of heat. Part of the heat can be fed
back to keep the fuel cell hot. The remainder of the heat can be
used to either heat buildings or to drive motor generators that in
turn generate more electricity. The high temperature also
vaporizes the water produced, making its removal a cinch.
The DaimlerChrysler NECAR 4 employed yet another kind of
fuel cell called a proton exchange membrane fuel cell. This fancy
sounding name means that the electrolyte is not a liquid at all.
Instead, a special polymer membrane is used that allows hydrogen
ions (protons) to scoot through it and carry the current. This
polymer membrane fuel cell can operate at much more reasonable
temperatures, even low enough that it is being considered as a
possible replacement for lithium batteries in laptop computers.
Again, platinum is the catalyst.
There are two other types of fuel cell that do not use platinum but
neither of these fuel cells will be used in your laptop computer.
They literally operate red hot, at temperatures between 600 to
1000 degrees Centigrade. You may also have read press
accounts about fuel cells using either methanol or gasoline
directly. These ideas are being pursued quite vigorously.
Finally, Charlie, I miss you greatly. Yes, I have plenty to read,
including that foot-high stack of magazines you left me. And yes,
stop bugging me; I walked four miles this morning. And, dear
readers, I leave you with a word spoken by Charlie''s courageous
wife at his service. After her own tribute to her husband, she
made us all smile with her parting admonition - "Exercise!"
Allen F. Bortrum