|
Amory Lovins |
The most likely candidate to power our transportation devices of the future is the simplest, most abundant gas—clean, efficient hydrogen.
Editor’s note: This is the first of a two-part
series of Amory B. Lovins's Hydrogen Primer. This article is a highly condensed
version of "Twenty Hydrogen Myths," a detailed paper from Rocky
Mountain Institute (RMI) which aims to address current hydrogen power myths. The
full article will be available on www.rmi.org later in June 2003.
RE - Insider, June 23, 2003 The potential cost-effective wind power in
the Dakotas could make as much hydrogen as the world now uses—enough, if used
in efficient fuel-cell vehicles, to displace all oil now used by U.S. highway
vehicles.
If there were no oil in Iraq, would we have just fought a war there? The
administration cited weapons of mass destruction as the main casus belli, but it
cannot be denied that U.S. interest and policies in the region are influenced,
and perceived to be influenced, by our interest in oil. Yet, just as our
transportation fuels have transitioned from clunky, awkward solids to
easy-to-store liquids (coal to oil) during the past two hundred years, they are
likely to transition again, from liquids to gases. The most likely candidate to
power our transportation devices of the future is the simplest, most abundant
gas—clean, efficient hydrogen.
The chairs of eight major oil and car companies have said the world is entering
the oil endgame and the start of the Hydrogen Era. A Shell planning scenario in
2001 envisaged a radical, China-led leapfrog to hydrogen (now clearly underway),
making world oil use stagnate until 2020 and then fall. President Bush's 2003
State of the Union message further emphasized the commitment to developing
hydrogen-fuel-cell cars he'd announced a year earlier (FreedomCAR).
Yet many diverse authors have lately criticized hydrogen. Some call it a
smokescreen to hide White House opposition to raising car efficiency using
conventional technology, or fear that working on hydrogen would divert effort
from rather than complement renewable energy deployment/adoption. Some simply
presume that if this President believes something, it must not be true. Most
reflect errors meriting a tutorial on basic hydrogen facts. But before I discuss
the transition to hydrogen, here are four key points about H2 that are not
always articulated:
1) Hydrogen makes up about 75 percent of the known universe, but is not an
energy source like oil, coal, wind, or sun. Rather, it is an energy carrier—a
molecule that, like electricity, can carry useful energy to users. Hydrogen is
an especially useful carrier because like oil and gas, but unlike electricity,
it can be stored in large amounts.
2) The reason hydrogen isn't an energy source is that it's almost never found by
itself, the way oil and gas are. Instead, it must first be freed from chemical
compounds in which it's bound, using heat and catalysts to "reform"
hydrocarbons or carbohydrates, electricity to "electrolyze" water, or
other methods, including experimental processes based on light, plasmas, or
microorganisms. All devices that produce hydrogen on a small scale, at or near
the customer, are collectively called "hydrogen appliances."
3) Over two-thirds of the fossil-fuel atoms burned in the world today are
hydrogen. The debate is about whether getting rid of the last third (the
carbon), and even its combustion ("uninventing fire"), could be more
profitable and attractive than burning both the carbon and the hydrogen.
4) Hydrogen is the lightest molecule, eight times lighter than natural gas. Per
unit of energy, it weighs 64 percent less than gasoline or 61 percent less than
natural gas: 2.2 pounds of hydrogen has (within two percent) the same energy as
one U.S. gallon of gasoline, which weighs 6.2 pounds. Conversely, hydrogen is
bulky—per unit volume, hydrogen gas contains only 30 percent as much energy as
natural gas, and even at 170 times atmospheric pressure (170 bar), only six
percent as much energy as gasoline.
So much for the basics. Now for the currently prevalent myths:
1. A whole hydrogen industry would need to be developed from scratch.
Wrong. Hydrogen manufacture and use is already a large and mature global
industry. At least five percent of U.S. natural gas output is currently
converted into industrial hydrogen, half of which is used in refineries—mainly
to make gasoline and diesel fuel. Globally, about 50 million metric tons of
hydrogen is now made for industrial use, about 3–5 times America's
consumption. Nearly all hydrogen is extracted ("reformed") from fossil
fuels, mainly natural gas, because that's cheaper than electrolysis unless you
have extremely cheap electricity (generally well under two cents per
kilowatt-hour), or unless the hydrogen is a byproduct (about two percent comes
from electrolytic chlorine production).
2. Hydrogen is too volatile and explosive to use as a fuel.
Wrong. Although all fuels are hazardous, hydrogen's hazards are different from
and generally more easily managed than those of hydrocarbon fuels. It's 14.4
times lighter than air, four times more diffusive than natural gas, and 12 times
more diffusive than gasoline—so leaking hydrogen rapidly rises away from its
source. Also, it needs at least four times the concentration of gasoline fumes
to ignite, it burns with a nonluminous flame that can't scorch you at a
distance, and its burning emits no choking smoke or fumes—only water.
Hydrogen-air mixtures are hard to make explode. Hydrogen does ignite easily,
with only a tenth as much energy as natural gas, which a static spark can
ignite. However, unlike natural gas, ignited hydrogen burns at lower
concentrations than can explode, and it can't explode in open air. The 1937
Hindenburg disaster was investigated by NASA scientist Dr. Addison Bain in the
late 1990s. He found that probably nobody aboard was killed by a hydrogen fire;
the 35 onboard who died as a result of the fire were killed by jumping out or by
the burning propeller-engine diesel fuel, flammable furnishings, and dirigible
itself, which—coated with a paste containing aluminum powder and chemically
similar to rocket fuel—was easily set alight by a spark. The clear hydrogen
flames swirled harmlessly above the 62 surviving passengers as they rode the
flaming dirigible safely to earth.
3. Making hydrogen uses more energy than it yields, making it impractical.
It would violate the laws of physics to convert any kind of energy into a larger
amount of another kind of energy. Hydrogen is no exception, and neither are
today's energy forms. Converting gasoline from crude oil is generally 75–90
percent efficient from wellhead to retail pump and electricity from fossil fuel
is only about 30–35 percent efficient from coal to retail meter. Hydrogen is
typically converted at efficiencies around 72–85 percent in natural-gas
reformers (thermochemical devices that separate hydrogen from carbon) or around
70–75 percent in electrolyzers. (These efficiencies are all reduced by 15
percent because a different definition of the hydrogen's energy content, called
"Lower Heating Value," is appropriate for its use in fuel cells than
is used to measure sales of fossil fuels.) But hydrogen's greater end-use
efficiency can more than offset its conversion loss. From wellhead to car tank,
oil is typically 88 percent efficient (the lost energy mainly fuels refining and
distribution). From car tank to wheels, gasoline is typically 16 percent
efficient. The average contemporary vehicle is thus about 14 percent efficient
well-to-wheels. A hybrid vehicle like the Toyota Prius nearly doubles the
gasoline-to-wheels efficiency to 30 percent and the total to 26 percent. But an
advanced fuel-cell car's 70 percent natural-gas-well-to-hydrogen-in-the-car-tank
efficiency, times 60 percent tank-to-wheels efficiency, yields 42 percent—three
times higher than the normal gasoline car or one and a half times higher than
the gasoline-hybrid-electric car. Thus the energy lost in making hydrogen is
more than made up by its extremely efficient use, saving both fuel and money.
4. Delivering hydrogen to users would consume most of the energy it contains.
Wrong. Two Swiss scientists recently analyzed the energy needed to compress or
liquefy, store, pipe, and truck hydrogen. Their net-energy figures are basically
sound—but their widely quoted conclusion that because hydrogen is so light,
"its physical properties are incompatible with the requirements of the
energy market" is not. In fact, their paper, published by the competing
Methanol Institute, simply catalogues certain hydrogen processes that most in
the industry have already rejected, except in special niche markets, because
they're too costly, including pipelines many thousands of kilometers long,
liquid-hydrogen systems (except for rockets and aircraft), and delivery in steel
trucks weighing more than one hundred times as much as the hydrogen carried.
The authors also focus almost exclusively on the costliest production method—electrolysis.
They admit that reforming fossil fuel is much cheaper, but reject it because,
they claim, it releases more CO2 than simply burning the original hydrocarbon.
That ignores the hydrogen's more efficient use: even under conservative
assumptions about car design, a good natural-gas reformer making hydrogen for a
fuel-cell car releases between forty and sixty-seven percent less CO2 per mile
than burning hydrocarbon fuel in an otherwise identical gasoline-engine car,
because the fuel cell is 2–3 times more efficient than the engine.
Even more fundamentally, the Swiss authors analyzed only costly centralized ways
to make hydrogen. Most industry strategists suggest—at least for the next
couple of decades—decentralized production at or near the customer, using the
excess off-peak capacity of existing gas and electricity distribution systems
instead of building the new hydrogen distribution infrastructure whose costs the
Swiss analysis finds so excessive.
5. Hydrogen can't be distributed in existing pipelines, requiring costly new
ones.
Wrong. If remote, centralized production of hydrogen eventually did prove
competitive or necessary, existing gas transmission pipelines could generally be
converted by adding polymer-composite liners, similar to those now used to
renovate old water and sewer pipes, plus a hydrogen-blocking coating or liner,
and by converting the compressors. Even earlier, existing pipelines could carry
a mixture of hydrogen, up to a certain level, to "stretch" natural
gas; users of fuel cells could separate the two gases with special membranes.
Some newer pipelines already have hydrogen-ready alloys and seals, and all
future ones should be made hydrogen-compatible, as Japan intends for its big
Siberia-China-Japan gas pipeline. As for gas distribution pipes, many older
systems are already largely or wholly hydrogen-compatible because they were
originally built for "town gas" (synthetic gas that's up to sixty
percent hydrogen by volume), although burner-tips, meters, and other minor
components could require retrofit.
6. We don't have practical ways to use hydrogen to run cars, so we must use
liquid fuels.
Wrong. Turning wheels with electric motors has well-known advantages of torque,
ruggedness, reliability, simplicity, controllability, quietness, and low cost.
Heavy and costly batteries have limited battery-electric cars to small niche
markets, although the miniature lithium batteries now used in cellphones are
severalfold better than those used in battery cars. But California regulators'
initial focus on battery cars had a huge societal value because it greatly
advanced electric drivesystems. The question is only where to get the
electricity. Hybrid-electric cars now on the market from Honda and Toyota, and
soon from virtually all auto-makers, make the electricity with on-board
engine-generators, or recover it from braking. This gives the benefits of
electric propulsion without the disadvantages of batteries. Still better will be
fuel cells—the most efficient (50–70 percent from hydrogen to direct-current
electricity), clean, and reliable known way to make fuel into electricity.
Fuel cells reverse the high-school chemistry experiment—splitting water with
an electric current so hydrogen and oxygen bubble out of the test-tube—by
chemically recombining hydrogen and oxygen on a special membrane, at
temperatures as low as 160–190°F (much higher in some types), to produce
electricity, pure water, heat, and nothing else. Invented in 1839, fuel cells
have been widely used for decades in aerospace and military applications.
Breakthroughs since the early 1990s mean that, even in this decade, they'll
start becoming affordable. As for most other manufactured goods, real cost
should fall by about 15–30 percent for each doubling of cumulative production.
Used in the right place and manner, even today's hand-made fuel-cell prototypes
can compete in many buildings.
Testing of vehicular fuel cells is well advanced. Already, many manufacturers
have tens of fuel-cell buses and over a hundred fuel-cell cars on the road; a
German website (www.hydrogen.org/h2cars/overview/main00.html) reports 156
different kinds of fuel-cell concept cars and sixty-eight demonstration hydrogen
filling stations; Honda and Toyota are leasing fuel-cell cars; six other
automakers plan to follow suit during 2003–05; many kinds of military vehicles
are demonstrating more advanced fuel cells; ship, boat, scooter, and
recreational uses are emerging; and Fedex and UPS reportedly plan to introduce
fuel-cell trucks by 2008. A Deutsche Shell director predicted in 2000 that half
of all new cars and a fifth of the car fleet will run on hydrogen by 2010, while
the German Trans-port Minister forecast ten percent of new German cars.
Some automakers formerly assumed that they must extract hydrogen from gasoline
(or methanol) aboard cars, using portable reformers, for two reasons: tanks of
compressed hydrogen would be too big because hydrogen has so much less energy
per unit volume than liquid fuels, and it would be too hard or costly to shift
today's fueling infrastructure from gasoline to hydrogen. Both these problems
have now been solved, so few automakers still favor onboard gasoline reformers.
That's good, because they're very difficult and problematic, and would cut
gasoline-to-wheels efficiency to or below that of a good gasoline-engine car.
Since almost all automakers now agree that reformers should be at or near the
filling station, not aboard the car, there's no longer any reason to reform
gasoline: natural gas is much cheaper, and is easier to reform. Hydrogen will
thus displace gasoline altogether, without spending the energy and money to make
gasoline first. There is similarly little reason to "bridge" with
methanol, except perhaps to run fuel cells in very portable devices like vacuum
cleaners, cellphones, computers, and hearing aids.
Stay tuned………The final installment of Amory Lovins's condensed Hydrogen
Primer will be available next week as an RE Insider on SolarAccess.com.
About the Author
Amory Lovins, a MacArthur Fellow and consultant physicist, has advised the
energy and other industries for nearly three decades as well as the Departments
of Energy and Defense. Published in 28 books and hundreds of papers, his work in
about 50 countries—often with L. Hunter Lovins, with whom he co-founded Rocky
Mountain Institute (RMI) in 1982—has been recognized by the “Alternative
Nobel,” Onassis, Nissan, Shingo, and Mitchell Prizes, the Happold Medal, eight
honorary doctorates, and the Heinz, Lindbergh, Hero for the Planet, and World
Technology Awards. He advises industries and governments worldwide, and has
briefed 16 heads of state. He serves as CEO of RMI (www.rmi.org), an
independent, market-oriented, nonprofit applied research center. Much of its
work is synthesized in Natural Capitalism (www.natcap.org). RMI spun off E
SOURCE (www.esource.com) in 1992 and Hypercar, Inc. (www.hypercar.com), which he
chairs, in 1999. Lovins can be reached at ablovins@rmi.org
Replies to "A Few Basics About Hydrogen":