From: Glenn Morton (glennmorton@entouch.net)
Date: Sat Jul 19 2003 - 12:37:34 EDT
There was an article in Nature a couple of weeks ago which highlight the
problems facing the US in energy production and consumption and the supposed
future switch over to hydrogen. the article is: Paul M. Grant, “Hydrogen
Lifts Off—with a Heavy Load,” Nature, 424(2003):129-130
The article points out that the US would need to generate 230,000 tonnes of
hydrogen daily to replace oil. This is enough to fill 13,000 Hindenburg's.
Grant also notes that hydrogen is not a primal energy source. More energy
is used to extract hydrogen than we get from its use. Grant notes that if we
use electricity to generate the hydrogen there are problems:
" For simplicity, and to bypass issues of carbon and carbon dioxide
sequestration, let us assume that hydrogen is obtained by ‘splitting’ water
with electricity—electrolysis. Although this isn’t the cheapest industrial
approach to ‘make’ hydrogen, it illustrates the enormous production scale
involved—about 400 gigawatts of continuously available electric power
generation have to be added to the grid, nearly doubling the present US
national average power capacity. The number of new power plants that would
need to be build—based on presently available technologies—to meet this
demand is roughly 800 natural-gas-fired combined-cycle units generating
500-megawats, or 500 800-megawatt coal-fired units, 200 Hoover Dams (two
gigawatts each), or 100 French-type nuclear clusters (four reactors, about
one gigawatt each).”
“The average capital cost of building an electric power plant is $1,000 per
kilowatt (with considerable variance), which would mean new investment of at
least $400 billion (one-twentieth of US gross domestic product). This does
not include the storage and delivery costs that would be incurred for a
complete transformation to a surface transport system running on hydrogen
instead of petroleum. A daunting prospect, but not impossible. To get the
daily hydrogen ration of 230,000 tonnes, just over two million tones of
water is required. Even this vast amount of water expelled as ‘exhaust’ will
be recycled to the environment in several days, unlike carbon dioxide.”
Paul M. Grant, “Hydrogen Lifts Off—with a Heavy Load,” Nature,
424(2003):129-130
In 1999, estimates put 42% of the world's primary energy use being used to
generate electricity. (Richard C. Duncan, “World Energy Production,
Population Growth, and the Road to the Olduvai Gorge,” Population and
Environment: A Journal of Interdisciplinary Studies, 22:5:503-522. May 2001,
p. 505-506).
If this is true, then as oil and natural gas get scarce the problem of
generating electricity for the purpose of turning it into hydrogen becomes
more difficult. Duncan's article notes that 1 J of electricity is worth 3 J
of gas because of conversion losses. and natural gas is now getting scares,
at least in the North American market. This same 1 J for 3 will apply to the
hydrogen economy which raises serious questions about the wisdom of spending
energy profligatly for hydrogen in the face of declining supplies of oil and
natural gas.
The investment to convert to hydrogen and the associated energy loss is a
direction we may not wish to go. Why pay a high price of hydrogen energy
when one can get a cheaper per joule return from any other energy source?
This archive was generated by hypermail 2.1.4 : Sat Jul 19 2003 - 12:37:59 EDT