[A-List] The Myth of the Hydrogen Economy

[Dale Allen Pfeiffer]

The Myth of the Hydrogen Economy
Dale Allen Pfeiffer in Dale Allen Pfeiffer's Blog
Tuesday 03 of January, 2006
There is a lot of talk about the hydrogen economy. It
is at best naïve, and at worst it is dishonest. A
hydrogen economy would be a pitiful, impoverished
thing indeed.

There are a number of problems with hydrogen fuel
cells. Many of these are engineering problems which
could probably be worked out in time. But there is one
basic flaw which will never be overcome. Free hydrogen
is not an energy source; it is rather an energy
carrier. Free hydrogen does not exist on this planet,
so to derive free hydrogen we must break the hydrogen
bond in molecules. Basic chemistry tells us that it
requires more energy to break a hydrogen bond than to
form one. This is due to the Second Law of
Thermodynamics, and there is no getting around it. We
are working on catalysts which will help to lower the
energy necessary to generate free hydrogen, but there
will always be an energy loss, and the catalysts
themselves will become terribly expensive if
manufactured on a scale to match current
transportation energy requirements.

All free hydrogen generated today is derived from
natural gas. So right off the bat we have not managed
to escape our dependency on nonrenewable hydrocarbons.
This feedstock is steam-treated to strip the hydrogen
from the methane molecules. And the steam is produced
by boiling water with natural gas. Overall, there is
about a 60% energy loss in this process. And, as it is
dependent on the availability of natural gas, the
price of hydrogen generated in this method will always
be a multiple of the price of natural gas.

Ah, but there is an inexhaustible supply of water from
which we could derive our hydrogen. However, splitting
hydrogen from water requires an even higher energy
investment per unit of water (286kJ per mole). All
processes of splitting water molecules, including
foremost electrolysis and thermal decomposition,
require major energy investments, rendering them
unprofitable.

Hydrogen advocates like to point out that the
development of solar cells or wind farms would provide
renewable energy that could be used to derive
hydrogen. The energy required to produce 1 billion kWh
(kilowatt hours) of hydrogen is 1.3 billion kWh of
electricity. Even with recent advances in photovoltaic
technology, the solar cell arrays would be enormous,
and would have to be placed in areas with adequate
sunlight.

We must also consider the water from which we derive
this hydrogen. To meet our present transportation
needs, we would have to divert 5% of the flow of the
Mississippi River. This would require yet more energy,
further reducing the profits of hydrogen. This water
would then have to be delivered to a photovoltaic
array the size of the Great Plains. So much for
agriculture.

The only way that hydrogen production even approaches
practicality is through the use of nuclear plants. To
generate the amount of energy used presently by the
United States, we would require an additional 900
nuclear reactors, at a cost of roughly $1 billion per
reactor. Currently, there are only 440 nuclear
reactors operating worldwide. Unless we perfect fast
breeder reactors very quickly, we will have a shortage
of uranium long before we have finished our reactor
building program.

Even hydrogen fuel derived from nuclear power would be
expensive. To fill a car up with enough hydrogen to be
equivalent to a 15 gallon gas tank could cost as much
as $400. If the hydrogen was in gaseous form, this
tank would have to be big enough to accommodate
178,500 liters. Compressed hydrogen would reduce the
storage tank to one tenth of this size. And liquefied
hydrogen would require a fuel tank of only four times
the size of a gasoline tank. In other words, a 15
gallon tank of gasoline would be equivalent to a 60
gallon tank of hydrogen. And, oh yes, to transport an
equivalent energy amount of hydrogen to the fueling
station would require 21 times more trucks than for
gasoline.

Compressed and liquefied hydrogen present problems of
their own. Both techniques require energy and so
further reduce the net energy ratio of the hydrogen.
Liquid hydrogen is cold enough to freeze air, leading
to problems with pressure build-ups due to clogged
valves. Both forms of hydrogen storage are prone to
leaks. In fact, all forms of pure hydrogen are
difficult to store.

Hydrogen is the smallest element and, as such, it can
leak from any container, no matter how well sealed it
is. Hydrogen in storage will evaporate at a rate of at
least 1.7% per day. We will not be able to store
hydrogen vehicles in buildings. Nor can we allow them
to sit in the sun. And as hydrogen passes through
metal, it causes a chemical reaction that makes the
metal brittle. Leaking hydrogen could also have an
adverse effect on both global warming and the ozone
layer.

Free hydrogen is extremely reactive. It is ten times
more flammable than gasoline, and twenty times more
explosive. And the flame of a hydrogen fire is
invisible. This makes it very dangerous to work with,
particularly in fueling stations and transportation
vehicles. Traffic accidents would have a tendency to
be catastrophic. And there is the possibility that
aging vehicles could explode even without a collision.

On top of this, we must consider the terrific expense
of converting from gasoline to hydrogen. The
infrastructure would have to be built virtually from
scratch, at a cost of billions. Our oil and natural
gas based infrastructure evolved over the course of
the past century, but this transition must be pulled
off in twenty years or less.

Automobile engineers and others within the industry do
not believe we will ever have a hydrogen economy.
Daimler-Chrysler has admitted as much. Rather than
developing a hydrogen economy, it makes more sense—and
will always make more sense—to buy a more efficient
car, ride public transport, bicycle or walk.

Posted on Tuesday 03 of January, 2006 [12:26:17 UTC


		
__________________________________________ 
Yahoo! DSL – Something to write home about. 
Just $16.99/mo. or less. 
dsl.yahoo.com