The Hydrogen Economy

The expression “hydrogen economy” is appearing more and more frequently in
the headlines and on the bookstands. As recently as February 2005 the governor
of Florida unveiled his Hydrogen Energy Technologies Act and broke ground on
the first hydrogen energy station in Florida. The previous year he announced
a statewide initiative to grow the hydrogen industry, and he’s certainly not
ahead of the curve. Iceland already has plans to be the world’s first hydrogen
economy. Hawaii is beginning to convert its solar and geothermal resources into
hydrogen for energy. California has its own hydrogen superhighway, and several
years ago the governor of New York participated in a ribbon-cutting ceremony
opening a new manufacturing facility in New York that would build hydrogen fuel
cell systems for both industry and for individual homes.

To decide what’s going on and whether it’s for real, let’s look at recent newspapers
– and the gas pump. The Wall Street Journal (Feb. 28, 2005) carried a small
story titled, “Gas Prices Rise Despite Greater Supply.” The article states that
many analysts are predicting prices as high as $2.50 per gallon for gasoline
during the coming year, and the price is expected to continue to rise.

Production of energy within the United States, especially from petroleum, has
not kept pace with U.S. usage, driving up imports. The United States currently
imports 55 percent of its oil, a number that is expected to increase to 68 percent
by 2025.[1] Demand for electricity is expected to increase by 45 percent and
natural gas by greater than 50 percent.[2] Other consuming countries are also
entering the picture, in particular China and India. Their demand for petroleum
will complicate world demand and increase the price pressure within the United
States.

Nearly all Americans would agree that we need to be less dependent on fuel
imports. Although nobody knows when fossil fuel will run out, everyone knows
that it eventually will. So it’s better to begin finding an alternative now
than later. We can save $100 billion per year if we find our energy sources
internally (i.e., within the United States).[3] We can also reduce emissions
and strengthen our economy if we select the new source wisely.

Attention-Getter

Renewable energy is gaining increased attention because it’s just that – renewable.
Biomass, geothermal, hydropower, ocean, solar, wind and hydrogen are all natural
sources of energy. Recently hydrogen has been working its way toward the top
of the list. There was little interest in 1970 when electrochemist John O’M.
Bockris coined the phrase “hydrogen economy,” but the fuel embargo in 1973 spurred
an interest in hydrogen and the development of hydrogen fuel cells for conventional
commercial applications.[4]

In the 1980s, the Soviets flew a commercial airliner partially fueled by hydrogen
and an American flew a private aircraft propelled by hydrogen.[5] In the 1990s,
the transportation industry took an interest in hydrogen with the advent of
fuel-cell-powered buses and automobiles. In addition, acceptance of hydrogen
was improved when retired NASA engineer Addison Bain concluded that the Hindenburg
accident was not actually caused by hydrogen but by static electricity and the
highly flammable skin material of the airship.[4] As previously mentioned, Iceland
announced that it would be the first country with a hydrogen economy. Germany
has opened hydrogen fueling stations.

In this decade the automobile companies have continued to produce cars based
on either hydrogen or hybrid energy systems, and President Bush announced a
hydrogen fuel initiative in his 2000 State of the Union Address. The federal
budget in 2005 includes $225 million for hydrogen as a source of energy and
the proposed 2006 budget requests $260 million.

Usually we expect a debate to converge on a single optimum approach for as
serious an issue as the coming energy crisis, but just the opposite is happening.
It is diverging. Some say that cost is holding up the hydrogen economy, but
it is more likely that either indecision (or too many independent decisions)
is the culprit. That’s understandable when one examines what comprises the hydrogen
economy. The only single point that has (fairly) unanimous agreement is that
hydrogen is an optimum potential source of future energy. Beyond that, every
other component of the future energy equation is a variable, a variable with
many values. It should be no surprise that the average American is confused.

Generally, for renewable hydrogen resources, 25 kilograms of hydrogen displace
approximately one barrel of oil with a corresponding reduction in greenhouse
gas emissions of 3 kilograms of carbon dioxide for each kilogram of hydrogen.[6]
Thus, one realizes a double financial benefit from reduced air pollution when
one chooses clean methods of hydrogen production. So although the path is not
clear, the goal of a hydrogen economy has obvious merit.

Enter Hydrogen

Energy must be created, delivered and used, so there must be a source, production
techniques, a transportation system, methods of storage and types of consumption.

The Two Primary Sources of Hydrogen

We have all seen a drawing of the hydrogen atom, the first element in the chemical
table: a large globe, or nucleus, being orbited by a small sphere, the single
electron. But let’s not be led astray by hydrogen’s apparent simplicity. The
cliché “there’s good news and bad news” holds. The good news is that hydrogen
is incredibly abundant. It comprises 70 percent of the Earth’s surface,[7] 75
percent of the mass of the universe and 90 percent of the molecules.[8]

Although hydrogen is plentiful, the bad news is that hydrogen is it seldom
remains in its pure state, preferring to combine with other elements to form,
for example, water and hydrocarbons (such as methane), the two primary sources
for hydrogen today.

The 11 Hydrogen Production Techniques

To use hydrogen as an energy source, it has to be separated from the other
elements. That is, oxygen has to be removed from the water molecule, or carbon
must be removed from methane. Complexity arises from the fact that there are
at least 11 technologies available to do this[9]:

  • Steam methane reformation (SMR) (50 percent of hydrogen worldwide production);
  • Partial oxidation (POX);
  • Coal gasification (CG) (about 18 percent of hydrogen worldwide production);
  • Electrolysis (4 percent of hydrogen worldwide production);
  • Biomass;
  • Thermal cracking;
  • Photochemical;
  • Photo-electrochemical;
  • Thermochemical (there are six solar versions of these: thermolysis, thermochemical
    cycles, reforming, solar cracking, solar gasification and solar carbothermic
    reduction[10];
  • Thermal decomposition (high-temperature systems using solar thermal, geothermal,
    biomass and nuclear energy); and
  • Pyrolysis.

The first three are the most technologically “ready” but are not renewable
and depend on some form of natural gas, which means that they will eventually
become more expensive. They also produce carbon dioxide as a byproduct. (Remember
that hydrogen use is only a clean form of energy if the process to produce it
is also clean.)

The fourth technology, electrolysis, is the production of chemical changes
by passage of an electric current through an electrolyte. This can be accomplished
by various means such as solar, wind, nuclear and geothermal, and since these
are renewable, they should not increase in cost over the coming decades. When
water is the electrolyte, the result is hydrogen and oxygen.

Wind generation of electricity, as one example, has averaged a growth of 32
percent per year from 1995 through 2002. Some European countries are already
obtaining significant amounts of their electricity from wind, and as the available
energy produced in this manner has increased, so has public support. Its largest
obstacle is the lack of accessibility. If wind were our only energy provider,
hydrogen pipelines or electric transmission lines would have to carry the energy
from, for example, the Great Plains to the remainder of the United States.

Biomass (plant-derived materials) has been the largest renewable energy source
in the United States since 2000, providing 47 percent of all renewable energy
and 4 percent of the total energy in 2003.[11] It consumes agricultural and
forest residues along with other organic byproducts. Ethanol and bio-diesel
fuel – derived primarily from plant matter and agricultural products such as
corn – are becoming of increasing importance in the transportation industry.

The United States has the capability of supporting more than one of these techniques
for hydrogen energy production. The eastern half of the United States, for example,
has great potential for biomass and the western half for solar and wind energy.[10]
Any of the remaining six are also possible, especially if there are breakthroughs.

Transportation

Once hydrogen has been produced, it must be safely delivered to various parts
of the country in individual containers such as small cylinders for decentralized
use or through pipelines for centralized distribution. Regardless of the type
of distribution, the technical problems for both liquid (cryogenic) and gaseous
hydrogen containment are extensive. The hydrogen molecule is small, which makes
compressing and sealing its container difficult. Liquefaction requires reducing
the temperature and maintaining it at near absolute zero, a formidable task
but already done.

Other methods[12] of hydrogen distribution include chemical compounds, absorptive
metallic alloys, carbon or substrates. These may be more easily transported
than pure liquid or gas, but the technologies still need significant development.

Hydrogen can also be used to generate electricity directly for transmission
over an electric grid. At this time, the costs for the hydrogen pipelines and
the additional electric lines needed are comparable.[13] Regardless, additional
electric lines will inevitably be needed since transmission line saturation
is already occurring.[14]

Storage

Storage is currently considered the biggest challenge to the future of the
hydrogen economy. The problems associated with the storage of gaseous or liquid
hydrogen are similar to those associated with its transport, thereby raising
serious questions: Does the average American want a 10,000-pounds-per-square-inch
gas bottle in their vehicle? Is a hydrogen pipeline a security risk?

Other possibilities include chemical compounds, which offer a large variety
of mediums for storage. They are receiving considerable research attention.
Various metal and liquid hydrides, nanoparticles and carbon compounds are also
being investigated. Unfortunately, in many cases the advantage of the storage
medium is negated by the considerable energy that must be expended to extract
the stored hydrogen.

Uses

Hydrogen can be burned to produce energy in the form of heat or transformed
directly into electrical current. Using transportation (which consumes almost
two-thirds of our oil) as an example, vehicles can be powered by combustors,
hydrogen internal combustion engines (heat) or hydrogen fuel cells (electricity)
or a combination of any of those and a battery.

Thus begins the classic game of chicken and egg. The fuel supply method will
have a strong influence on the type of energy conversion system (combustion,
electric motor/generator) and vice versa. If automobile manufacturers knew for
sure which type of hydrogen fuel would be available for the consumer then they
could produce the vehicle. If energy providers knew what type of automobile
engine they were to service, they could supply the fuel. Which goes first? Which
is it, heat or electricity? No one wants to drive a vehicle without readily
available fuel. And no one wants to have a refueling station for nonexistent
vehicles.

The Future

It’s highly probable that if we were to tour a home in the year 2040, we would
never realize that we had entered the hydrogen era. When we turn on the light
switch, electrons will produce light and power the stove and cooling/heating
system. Except for the cleaner air, we might not even notice any difference
when we drive through the countryside. During our stop for coffee at the local
service station we would purchase fuel in our accustomed fashion before continuing
our journey.

In 35 years, it will all seem very simple and straightforward. But at the other
end of the power lines and at the beginning of the fuel line, very sophisticated
technology will be operating. Just what that technology will be needs to be
determined soon if it is to be available in 2040. When the light switch is turned
on, the electrons could be generated by a localized hydrogen combustor or from
a fuel cell in the home’s basement. They might also come from an external electric
grid. If it’s external, the grid could involve a fuel cell, solar or wind unit
that provides energy only for that home or for the housing area or industrial
complex, or it could be connected to a regional electric grid much as we have
today.

If the hydrogen economy seems confusing, all one has to do is review the numbers
to understand why. Mathematically, using just the technologies mentioned here,
there are more than 3,000 possible combinations of means for providing those
electrons at your switch. And it is undetermined how many technological barriers
are associated with those combinations. These are far too many even for a country
with the scientific resources of the United States.

Are these barriers hurdles or roadblocks? One generally goes over hurdles and
around roadblocks. Doing either is “just engineering,” but before the engineers
can go over or around, they have to identify and understand the barrier. Any
choices made, for example, between centralized or decentralized electric grids,
or gaseous versus liquid hydrogen combustors, or internal combustion engines
and fuel cells reduces the number of technical barriers.

Americans agree that something must be done to free us from dependency on foreign
oil and natural gas. Right now, with over three thousand possible solutions,
the number of potential barriers seems insurmountable. Decisions, commitments
and unbiased judgments need to come to bear to reduce those barriers to a reasonable
and solvable number before we run out of energy. What a shame it would be to
have our grandchildren sit in darkness, surrounded by something that comprises
75 percent of the world’s surface and be helpless to use it.

Endnotes

  1. “President’s Hydrogen Initiative: A Clean and Secure Energy Future,” www.eere.energy.gov/hydrogenandfuelcells/presidents_initiative.html.
  2. Report of the National Energy Policy Development Group, May 2001, U.S. Government
    Printing Office, ISBN 0-16-050814-2.
  3. Renewable Hydrogen Forum, A Summary of Expert Opinion and Policy Recommendations,
    National Press Club, Washington, D.C., Oct. 1, 2003, Presented by American
    Solar Energy Society p. 10.
  4. “The History of Hydrogen” Fact Sheet Series, Facts H 1.008. www.hydrogenus.com/History-of-H2-Fact-Sheet.pdf
  5. The Hydrogen Economy The Next Great Economic Revolution, Jeremy Rifkin,
    Tarcher/Penguin, New York, NY, 2003.
  6. Renewable Hydrogen Forum, A Summary of Expert Opinion and Policy Recommendations,
    National Press Club, Washington, DC, Oct. 1, 2003, Presented by American Solar
    Energy Society p. 42.
  7. Hydrogen Technical Advisory Panel (HTAP) U.S. DOE, “Fuel Choice for Fuel
    Cell Vehicles.”
  8. “Hydrogen.” The Columbia Encyclopedia, Sixth Edition. Columbia University
    Press, 2001.
  9. Renewable Hydrogen Forum, A Summary of Expert Opinion and Policy Recommendations,
    National Press Club, Washington, D.C., Oct. 1, 2003, Presented by American
    Solar Energy Society p. 42.
  10. Ibid. p.22.
  11. The Hydrogen Economy, Opportunities, Costs, Barriers and R&D Needs,
    National Research Council and National Academy of Engineering of the National
    Academies, The National Academies Press, Washington D.C., 2004.
  12. Ibid. p. 41.
  13. Renewable Hydrogen Forum, A Summary of Expert Opinion and Policy Recommendations,
    National Press Club, Washington, D.C., Oct. 1, 2003, Presented by American
    Solar Energy Society p. 16.
  14. Ibid. p. 59.