An
electrolyzer uses an electric current to separate water into its
components-hydrogen and oxygen. The electricity enters the water at the
cathode, a negatively charged electrode, passes through the water and exists
via the anode, the positively charged electrode. The hydrogen is collected
at the cathode and oxygen is collected at the anode.| Origin | Amount in billions Nm3/year |
Percent |
| Natural gas | 240 | 48 |
| Oil | 150 | 30 |
| Coal | 90 | 18 |
| Electrolysis | 20 | 4 |
| TOTAL | 500 | 100 |
Sources
U.S. Department of Energy
National Hydrogen Association
How much does hydrogen cost?
The estimated costs for producing and delivering hydrogen to the
fueling station using today’s technologies vary from $2.10/gallon of
gasoline equivalent (gge) to $9.10/gge. These hydrogen costs do not include
highway taxes and do include the increased fuel efficiency of fuel cell
vehicles compared to gasoline-powered hybrid electric vehicles. That is, the
driver of a fuel cell vehicle would pay the same amount to travel 100 miles
on hydrogen as the driver of a gasoline-powered hybrid electric vehicle
would pay for gasoline if the price was between $2.10/gallon to $9.10/gallon
to travel that same distance.
Source
National Academy of Engineering, "The Hydrogen Economy:
Opportunities, Costs, Barriers, and R&D Needs"(2004), Fig. 5-1
Projected costs using future technology if current R&D efforts are
successful would reduce the cost of hydrogen to the range between $1.75/gge
to $4.25/gge. Thus hydrogen is expected to be competitive with gasoline per
mile driven.
Source
National Academy of Engineering, "The Hydrogen Economy: Opportunities,
Costs, Barriers, and R&D Needs"(2004), Fig. 5-3
In addition, some NHA member companies are projecting that they can produce
and deliver hydrogen economically to fueling stations at costs as low as
$1.20/gallon of gasoline equivalent, again untaxed. After adding the average
US highway taxes (federal and state) of $0.43/gallon, hydrogen would still
be less expensive than gasoline per mile traveled.
VEHICLES
How do hydrogen vehicles work?
There are two main kinds, fuel cell vehicles and hydrogen internal
combustion engine (ICE) vehicles.
Fuel cell vehicles are electric cars. Hydrogen is pumped into a tank in the
car, just as with gasoline. The hydrogen gas is then fed into the fuel cell
where it is electrochemically converted into electricity -- with no
combustion, no moving parts, and no emissions other than water vapor. The
electricity is used to power the vehicle. A fuel cell is also 2-3 times more
energy efficient than a gasoline engine.
Hydrogen ICE vehicles use a regular combustion engine modified to use
gaseous hydrogen instead of liquid gasoline (much like a natural gas vehicle
is modified). They burn hydrogen, but since there is no carbon in hydrogen,
there are no CO2 emissions and only trace amounts of NOx (oxides
of nitrogen--the air we breathe is 79% nitrogen). Hydrogen ICE vehicles are
typically about 30% more efficient than comparable gasoline vehicles.
Both types can be hybridized for additional gains in efficiency, by adding
an electricity storage device like a battery or capacitor.
Source
Q&A with Dan Sperling, director of the Institute of Transportation Studies;
associate director of the Energy Efficiency Center and professor of
Transportation Engineering and Environmental Policy at the University of
California, Davis.
If all cars ran on hydrogen, and all hydrogen was made from water, would
we run out of water?
Conversion of the current U.S. light-duty fleet (some 230 million
vehicles) to fuel cell vehicles would require about 100 billion gallons of
water/year to supply the needed hydrogen (1). Domestic personal
water use in the United States is about 4800 billion gallons/year.
The U.S. uses about 300 billion gallons of water/year for the production of
gasoline (2), and about 70 trillion gallons of water/year for
thermoelectric power generation (3).
Solar and wind power do not require water for their electricity generation.
So not only do these resources provide sustainable carbon-free energy, they
reduce the water requirements for power generation.
Sources
Turner, John A.,
"Sustainable Hydrogen Production" Science, Vol 305, Issue 5686, 972-974, 13
August 2004
1) For an estimate of the amount of water needed for hydrogen-powered fuel
cell vehicles, assume a vehicle fuel economy of 60 miles per kg of H2, that
vehicle miles traveled = 2.6 X 10^12 miles/year (found at ),and that 1
gallon of water contains 0.42 kg of H2. Total water required for the U.S.
fleet = (2.6 X 10^12 miles/year)(1 kg of H2/60 miles)(1 gal H2O/0.42 kg of
H2) = 1.0 X 10^11 gallons of H2O/year. This represents the water used
directly for fuel. If one considers all water uses along the chain; for
example, from construction of wind farms to the electrolysis systems (life
cycle assessment), then the total water use would be in the range of 3.3 X
10^11 gallons H2O/year.
2) This is a life cycle analysis (M. Mann and M. Whitaker, unpublished
data). The United States used about 126
billion gallons of gasoline in 2001 [see link above].
3) See
http://water.usgs.gov/pubs/circ/2004/circ1268/
How viable are hydrogen vehicles as an alternative to gasoline-powered
cars?
In many ways, they are more viable than gasoline. A fuel cell electric
vehicle is better suited to modern vehicles that increasingly use electrical
systems in place of mechanical and hydraulic to steer, brake, and control
the various functions of the vehicle. Also, in a fuel cell vehicle, the
entire powertrain can be consolidated into a flat "skateboard" chassis,
providing automakers much design freedom in latching all sorts of different
vehicle bodies on to the chassis -- without having to work around a
protruding, heat-producing engine and large mechanical driveline. A fuel
cell is also 2-3 times more energy efficient than a gasoline engine.
Other vehicles that use hydrogen in a regular combustion engine are also
very viable. They use existing engine technology, modified to use gaseous
hydrogen. Hydrogen ICE vehicles are about 30% more efficient than comparable
gasoline vehicles and produce ultra-low emissions, with no CO2.
Source
Q&A with Dan Sperling, director of the Institute of Transportation Studies;
associate director of the Energy Efficiency Center and professor of
Transportation Engineering and Environmental Policy at the University of
California, Davis and the National Hydrogen Association
What happens to the tank in my car if I get rear-ended?
Hydrogen
tanks, whether they are filled with gaseous or liquid hydrogen are
incredibly strong-MUCH stronger than the gasoline tanks found in vehicles
today. For example, this car was dropped on its back end from 90 feet
(reaching 52 mph as it hit the ground), with a hydrogen tank secured in the
trunk. The tank was undamaged and no hydrogen was leaked.
Source
Sandia National Laboratories
Will I ever be able to buy a hydrogen-powered vehicle?
Every major automaker is developing hydrogen fuel cell vehicles, although
some are focusing on internal combustion engines instead of fuel cells.
Existing cars can be converted to run on hydrogen, and several major car
companies either have demonstration hydrogen cars or are due to release them
in the next few years. The successful development of advanced hydrogen
storage systems will accelerate the introduction of truly clean fuel cell
vehicles.
There is at least one automaker planning to begin selling them to the public
at a reasonable price as early as 2009, and several aiming for a few years
after that. But this depends on fuel suppliers building more hydrogen
fueling stations and the government offering incentives to buyers (as they
do now for hybrid vehicles).
Source
U.S. Department of Energy and Q&A with Dan Sperling, director of the
Institute of Transportation Studies; associate director of the Energy
Efficiency Center and professor of Transportation Engineering and
Environmental Policy at the University of California, Davis.
SAFETY
Is hydrogen safe?
Most fuels have high energy content and must be handled properly to be safe.
Hydrogen is no different. In general, hydrogen is neither more nor less
inherently hazardous than gasoline, propane, or methane. As with any fuel,
safe handling depends on knowledge of its particular physical, chemical, and
thermal properties and consideration of safe ways to accommodate those
properties. Hydrogen, handled with this knowledge, is a safe fuel.
Hydrogen has been safely produced, stored, transported, and used in large
amounts in industry by following standard practices that have been
established in the past 50 years. These practices can be emulated in
non-industrial uses of hydrogen to attain the same level of routine safety.
View our Hydrogen Safety fact sheet (215Kb PDF)
Source
National Hydrogen Association
If hydrogen has a wider flammability range than gasoline, doesn't that
make it unsafe to use?
While hydrogen has a wider flammability range than gasoline, the range
is only a piece of the story when considering the likelihood of a fire
resulting from hydrogen escaping into the atmosphere. Each fuel has
different properties that must be considered along with flammability range.
For example: Gasoline's narrow flammability range is a bit misleading, since
this range can easily and often be reached through normal consumer handling
of gasoline and certainly if spilled. There are of course gasoline fires
but, as we know, fires certainly don't occur every time gasoline vapors are
released to the open air, because the vapors fail to find an ignition source
in time.
Hydrogen has a wider flammability range, but because it is lighter than air
(50 times lighter than gasoline vapors and even lighter than helium) and
diffuses 12 times faster than gasoline vapors do, it is very difficult for
hydrogen gas to find a suitable ignition source in an open environment, like
a fueling station.
Hydrogen systems used for vehicular fueling are designed to provide public
safety just as gasoline systems are designed to do. While both fueling
systems utilize break-away hoses, shear valves, and monitoring systems,
hydrogen systems go a step further.
Hydrogen fuelers are designed as "closed" systems, meaning that the fuel is
not exposed to the atmosphere - unlike gasoline which can be spilled fairly
easily during refueling. This closed system design approach keeps hydrogen
always within proper containment and does not allow oxygen or air to mix
with the fuel, thereby eliminating one of the required combustion elements
needed to create a fire. This further mitigates hydrogen's low ignition
energy property, compared to gasoline, by never allowing a spark or ignition
source to have any ability to interact with the hydrogen gas.
Finally, the National Fire Protection Association (NFPA) and the
International Code Council (ICC) have incorporated hydrogen into their
standards and model codes. These codes reflect the differences in properties
between gasoline and hydrogen (and natural gas as well) through requirements
related to setback distances, control systems, and other public safety
elements.
Source
Shell Hydrogen LLC
Is hydrogen harmful to breathe?
Accidentally breathing a small amount of hydrogen won't harm you. Hydrogen
is non-toxic to humans, animals and the envionment. Like other commonly-used
gases, hydrogen displaces, or pushes away, oxygen. If the oxygen you were
trying to breathe was displaced by so much hydrogen that you were breathing
very little oxygen, problems could result. Since hydrogen disperses (rises
and spreads out) very quickly, there’s a very low risk of breathing too
much.
Did hydrogen cause the Hindenburg accident?
The
fire that destroyed the Hindenburg in 1937 gave hydrogen a misleading
reputation. Hydrogen was used to keep the airship buoyant and was initially
blamed for the disaster. An investigation by Addison Bain in the 1990s
provided evidence that the airship's fabric envelope was coated with
reactive chemicals, similar to solid rocket fuel, and was easily ignitable
by an electrical discharge. The Zeppelin Company, builder of the Hindenburg,
has since confirmed that the flammable, doped outer cover is to be blamed
for the fire.
For more
information, view a short video (Real Media)
Source
National Hydrogen Association
How is burning hydrogen different than the reaction in the H-bomb?
Burning hydrogen, just like burning gasoline, natural gas, or a candle, is a
chemical reaction, which means that electrons get shifted around and new
compounds are made, like water, but the basic atoms remain the same.
The thermonuclear explosion from a hydrogen bomb is the consequence of a
nuclear fusion reaction. During this reacton, the two isotopes of
hydrogen, deuterium and tritium, collide at very high energy to fuse into
helium nuclei, releasing tremendous amounts of energy.
To get these rare isotopes of hydrogen to fuse requires extraordinary
temperatures (hundreds of millions of degrees). These temperatures are
supplied in a thermonuclear weapon (in this case, an H-bomb) by setting off
an atomic, or fission, bomb to trigger the fusion reaction.
However, commercial hydrogen gas contains no deuterium and no tritium.
Without these isotopes, it is physically impossible for ordinary hydrogen
gas to produce a thermonuclear reaction under any circumstances.
Source
U.S. Department of Energy
National Hydrogen Association
Source
National Hydrogen Association
ALL FAQs from national Hydrogen Association http://www.hydrogenassociation.org/general/faqs.asp
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