What
is Hydrogen?
Hydrogen is the simplest element known to man. An atom of
hydrogen has only one proton and one electron. It is also
the most abundant gas in the universe, and the source of
all the energy we receive from the sun. The sun is
basically a giant ball of hydrogen and helium gases. In a
process called fusion, four hydrogen atoms combine to
form one helium atom, releasing energy as radiation.
This radiation energy is our most abundant energy source.
It gives us light and heat and makes plants grow. It
causes the wind to blow and the rain to fall. It is
stored as chemical energy in fossil fuels. Most of the
energy we use originally came from the sun.
Hydrogen as a gas (H2), however, doesn't exist
naturally on earth. It is found only in compound form.
Combined with oxygen, it is water (H2O).
Combined with carbon, it forms organic compounds such as
methane (CH4), coal, and petroleum. It is
found in all growing things-biomass. It is one of the
most abundant elements in the earth's crust.
Most of the energy we use today comes from fossil fuels.
Only seven percent comes from renewable energy sources.
But people want to use more renewable energy. Usually it
is cleaner, and we won't run out of it. We won't run out
of hydrogen either.
Every day we use more fuel, principally coal, to produce
electricity. Electricity is a secondary source of energy.
Secondary sources of energy-energy carriers-are used to
store, move, and deliver energy in easily usable form. We
convert energy to electricity because it is easier for us
to transport and use. Try splitting an atom, building a
dam, or burning coal to run your TV. Energy carriers make
life easier.
Hydrogen is one of the most promising energy carriers for
the future. It is a high efficiency, low polluting fuel
that can be used for transportation in places where it is
difficult to use electricity. Since hydrogen gas is not
found in its nature state on earth, it must be
manufactured. There are several ways to do this.
How is Hydrogen Made?
Industry produces the hydrogen it needs by a process
called steam reforming. High-temperature steam separates
hydrogen from the carbon atoms in natural gas (CH4).
The hydrogen produced by this method isn't used as a
fuel, but in the manufacture of fertilizers and chemical
s and to upgrade the quality of petroleum products.
This is the most cost-effective way to produce hydrogen
today, but it uses fossil fuels both in the manufacturing
process and as the heat source. Another way to make
hydrogen is by electrolysis-splitting water into its
basic elements, hydrogen and oxygen. Electrolysis
involves passing an electric current through water to
separate the atoms (2H2O + electricity = 2H2
+O2). Hydrogen collects at the negatively
charged cathode and oxygen at the positive anode.
Hydrogen produced by electrolysis is extremely pure, and
electricity from renewable energy sources can be used,
but it is very expensive at this time. Today, hydrogen
from electrolysis is ten times as costly as natural gas
and three times as costly as gasoline per Btu.
On the other hand, water is abundant and renewable, and
technological advances in renewable electricity could
make electrolysis a more attractive way to produce
hydrogen in the future.
There are also several experimental methods of producing
hydrogen. Photoelectrolysis uses sunlight to split water
molecules into its components. A semiconductor absorbs
the energy from the sun and acts as an electrode to
separate the water molecules.
In biomass gasification, wood chips and agricultural
wastes are super-heated until they turn into hydrogen and
other gases. Biomass can also be used to provide the heat
energy. Scientists have also discovered that some algae
and bacteria produce hydrogen under certain conditions,
using sunlight as their energy source. Experiments are
underway to find ways to induce these microbes to produce
hydrogen efficiently.
Hydrogen Uses
At the present time, hydrogen's main use as a fuel is in
the NASA space program. Liquid nitrogen is the fuel that
has propelled the space shuttle and other rockets since
the 1970's. Hydrogen fuel cells power the shuttle's
electrical systems, producing pure water, which is used
by the crew as drinking water.
In the future, however, hydrogen will join electricity as
an important energy carrier. Hydrogen can be made safely
from renewable energy sources and is virtually
non-polluting. It is also versatile; it can be a fuel for
"zero-emissions" vehicles, to heat homes and
offices, to produce electricity, and to fuel aircraft.
Cost is the major obstacle.
The first widespread use of hydrogen will probably be as
an additive to transportation fuels. Hydrogen can be
combined with gasoline, ethanol, methanol, and natural
gas to increase performance and reduce pollution. Adding
just 5 percent hydrogen to gasoline can reduce nitrogen
oxide (NOX) emissions by 30 to 40 percent in today's
engines.
An engine converted to burn pure hydrogen produces only
water and minor amounts of NOX as exhaust. A few
hydrogen-powered transportation systems we have today?
(Just think of the thousands of filling stations across
the country, and production and distribution systems that
serve them.) Change will come slowly to this industry,
but hydrogen is a versatile fuel; it can be used in many
ways.
For example, hydrogen is a natural as aircraft fuel. It
high-energy contents means reduced weight and fuel
consumption compared to current jet fuel. Plus, it is
non-polluting. And converting to hydrogen fuel would be
much easier for aircraft-the infrastructure (support
system) is simpler. The space shuttle uses hydrogen fuel
cells (batteries) to run its computer systems. The fuel
cells basically reverse electrolysis-hydrogen and oxygen
are combined to produce electricity. Hydrogen fuel cells
are very efficient and produce only water as a
by-product, but they are expensive to build. With
technological advances, small fuel cells could someday
power electric vehicles and larger fuel cells could
provide electricity in remote areas.
Because of cost, hydrogen will not produce electricity on
a wide scale in the near future. It may, though, be added
to natural gas to reduce emissions from existing power
plants. A the production of electricity from renewables
increases, so will the need for energy storage and
transportation. Many of these sources-especially solar
and wind-are located far from population centers and
produce electricity only part of the time. Hydrogen may
be the perfect carrier for this energy. It can store the
energy and distribute it to wherever it is needed. It is
estimated that transmitting electricity long distances is
four times more expensive than shipping hydrogen by
pipeline.
The Future of Hydrogen
Before hydrogen can take its place in the U.S. energy
picture, many new systems must be designed and built.
There must be large production and storage facilities and
a distribution system. And consumers must have the
technology to use it. The use of hydrogen raises concerns
about safety. Hydrogen is a volatile gas with high energy
content. Early skeptics had similar concerns about
natural gas and gasoline-even about electricity. People
were afraid to let their children too near to light
bulbs. As hydrogen technologies develop, safety issues
will be addressed. Hydrogen can be produced, stored, and
used as safely as other fuels. The goal of the U.S.
Department of Energy's Hydrogen Program is for hydrogen
to produce ten percent of our total energy demand by the
year 2030. Hydrogen can reduce our dependence on foreign
oil and provide clean, renewable energy for the future. |
Here some cowboys are
riding into the sunset. Without hydrogen there would be
no sun, and the cowboys would have no where to ride when
their work is done.
Currently the price of using hydrogen for residential
electricitity is very high compared to that of water or
gas but is much more reusable and powerful. Now, NASA
uses hydrogen to powers its rockets into outerspace.
Hydrogen is a very explosive element as demonstrated in
this picture of a helium powered blimp exploding. For
this reason, and cost, hydrogen will not be used for
power in residential applications anytime soon. |
