HYDROGEN POWER

Introduction

Hydrogen is often referred to as a miracle fuel. Burning of hydrogen is a clean process with emissions being only water vapor. An inexhaustible resource of the element is the sea. Hydrogen fuel has the potential to be used to power automobiles, trains, aircraft and ships. Hydrogen can also be used to generate electricity for use in homes, business and industry. One pound of hydrogen fuel has three times the power of the same amount of Jet-A kerosene aircraft fuel. A hydrogen powered ramjet engine could achieve an aircraft speed of 25,000 mph. Hydrogen powered automobile engines will be powerful, highly efficient, clean, and quiet. But implementation of this technology is not without challenges.  Problems of availability, containment and distribution need to be solved.

The potential of hydrogen fuel has been known for a long time. In 1956, the US Air Force experimented with hydrogen powered aircraft engines by running one engine of a B-57 bomber on hydrogen. The Russians converted a TU-154 bomber to hydrogen use and the Europeans are experimenting with designing Airbus commercial aircraft using hydrogen fuel.

Hydrogen fuel development is occurring in the United States, Germany, Japan, Canada, Belgium, and Saudi Arabia. Dozens of companies, worldwide, are working on research, development and production of hydrogen fuel related products. These include storage devices, fuel cells, and products for the production of hydrogen. Ballard Power Systems of Canada has developed hydrogen fueled busses that are being tested at various locations in the United States. The busses are powered by hydrogen fuel-cells driving electric motors.

Technical Challenges in the use of Hydrogen

The problem with hydrogen is that it does not exist naturally anywhere on earth. None exists under the earth's surface and any existing in the atmosphere is so light that it will rise and escape into space. However, hydrogen is in unlimited supply as part of water. Hydrogen can be created by electricity via electrolysis that separates water molecules into hydrogen and oxygen. This requires a large amount of electrical power that, today, would have to come mainly from oil, coal, nuclear or hydro-electric power plants. Hydrogen can also be extracted from hydrogen compounds such as hydrochloric acid and methane gas. The extraction requires energy which would mainly come from electrical power or by chemical reaction. Also, the resources of such compounds are not limitless as with sea water.

Another problem with hydrogen is that it is exists as a gas until very low temperatures (-423^o F) making storage a problem. Storage of the lightweight hydrogen gas results in an excessively large storage tank if it is not pressurized. Practical storage of pressurized hydrogen would require pressures of up to 10,000 pounds-per-square-inch (PSI). Storing of liquid hydrogen is possible, but the gas needs to be cooled down and kept at extremely low temperatures to maintain liquefaction. Liquid hydrogen is hazardous to handle. 

A Potential Interim Technology--Sodium Borohydride Fuel as a Hydrogen Source

A potential source of hydrogen is from a Sodium Borohydride fuel (A compound of Sodium, Boron and Hydrogen). The Sodium Borohydride is converted by a catalytic converter into Borax and hydrogen. The hydrogen is used to power fuel cells that provide electricity for engines and the resulting liquid byproduct solution of Borax is stored in a separate tank. The Borax solution is offloaded during fueling and can be sold for products such as cleaning solutions.

 

Energy is required to produce the Sodium Borohydride. This energy would have to come from oil, coal, nuclear or hydroelectric power until a cheaper more efficient forms of renewable energy--such as solar cells--are cost effective for generating large amounts of energy. A second problem is the availability of the resources of chemicals (borates) to produce the sodium borohydride. But this may eventually be the best interim solution for a relatively clean source of hydrogen fuel.

Technologies Being Developed

For a hydrogen powered automobile to have a competitive range compared to gasoline powered cars, hydrogen fuel would have to be stored at 10,000 pounds-per-square-inch (PSI) pressure.  Although experiments are being done for high pressure tanks, the best that can be done today is 5000 PSI.  

Experimental hydrogen powered automobiles that were built by BMW and others used vacuum "super-insulated" tanks that stored liquid hydrogen at a low temperature. Newer tanks are being built with super-activated carbon and may possibly store liquid hydrogen safely for long periods at high pressure. However, no inexpensive, high capacity, light weight, storage tanks have been constructed to date. Advanced heat resistant storage tanks and sophisticated transfer systems will have to be developed.

Producing hydrogen from solar power has a great potential. H Power Corporation has built solar cell systems that provide continuous power to highway signs. During the day electricity from solar cells power the signs and also create hydrogen via the electrolysis of water. At night hydrogen fuel-cells provide the power.

Research and development is being accomplished in the production of hydrogen. Photovoltaic cells are being developed with higher efficiencies and lower costs. Direct photoelectrochemical water-splitting techniques known as photoelectrolysis achieve the production of hydrogen via immersing a semiconductor in water for direct decomposition into oxygen and hydrogen. This technology may allow for the large scale production of hydrogen by a clean electric power source.

Political Issues with the use of Hydrogen

For may years hydrogen has been though of as more volatile and dangerous than other substances such as gasoline. This believe has, in-part, come from memories of the Hindenburg dirigible disaster in 1937: an event that still remains as an obstacle to public acceptance of hydrogen fuel. The disaster may have been much worse if some other type of volatile substance had been used in the dirigible. Sixty two (62) of the 97 people aboard the burning ship survived. The light weight hydrogen gas rose clear of craft as it burned allowing people to escape underneath.  Most of those who were injured or killed were burnt by the burning diesel fuel (used for the engines). In contrast kerosene jet fuel clings and burns longer and few survive a burning jet airplane, even if an accident occurs on the ground.

It is interesting to note that if the aircraft that crashed into the World Trade Center buildings in New York had been powered by hydrogen fuel, the exploding hydrogen fuel may not have done as much damage. Burning hydrogen would have risen and dispersed rapidly and the intense heat caused by jet fuel may have been avoided.  Experts say that it was the heat that caused the  buildings to collapse.  

Despite some strong public objection to hydrogen, the U.S. government is working with industry in the development of hydrogen fuel technology. The Hydrogen Future Act of 1996 (H.R. 4138, law 104-271) set up a program for research, development, and demonstration of hydrogen fuel technology. Up to $40 million will be spent per fiscal year on this effort. In 2003, the Bush Administration has committed $1.9 billion to hydrogen energy development

Hydrogen Fuel for Automobiles

Hydrogen could be burned directly in a turbine type of engine that provides direct power to a car's drive shaft. The most likely alternative is the creation of electricity with hydrogen fuel cells. The electricity from the fuel cells drives electric motors.

Hydrogen fueled engines maybe the best alternative to low or zero emission electric automobiles. This technology would eliminate the problems of low power and short range with electrical cars run on batteries. Heating and air-conditioning are difficult with battery powered electrical vehicles.

Daimler-Benz AG company in Germany has built a hydrogen powered fuel-cell car. Fuel cells are provided by Ballard Power Systems. Polymer fuel-cells are used. Hydrogen and the car’s fuel tank is filled with methanol (a natural gas derivative). The methanol is passed through a converter to create the hydrogen. The problem is that this is, in effect, a burning process that creates a carbon dioxide emission.

Hydrogen Fuel for a Space Plane

Small, sophisticated, powerful engines will have to be developed in order for a commercial space plane to reach the speed and altitude required to achieve orbit or sub-orbit. Hydrogen will be a good candidate as the fuel for these engines. Hydrogen was the fuel for the Saturn rocket that took astronauts to the moon and is the fuel for the main engine of the space shuttle. A small powerful hydrogen fueled ramjet is feasible for a commercial space plane.

Summary

Most likely hydrogen will be the fuel of choice sometime in the 21st Century when more advanced storage and production technologies are developed. Oil, coal, and other fossil fuels will eventually run out. Hydrogen can be obtained from sea water and since its exhaust is water, it is a renewable source of essentially unlimited supply.

Electrolysis of sea water to create hydrogen will be possible when high efficiency solar photo voltaic cells are developed. Large cell arrays will create clean electricity for the electrolysis process. Methods will have to be developed for the economical transport, storage, and availability of the hydrogen fuel. Meanwhile, on board production of hydrogen from fuels such as Sodium Borohydride or methane is an interim solution.  There is some emissions other that water for these interim techniques.

Once hydrogen can be produced by clean methods and small inexpensive, safe, high pressure storage tanks are available, the fuel will result in pollution free cars, airplanes, ships and trains. The threat of oil spills such as caused by the Exxon Valdez grounding will become less likely with less oil being transported. The U.S. and other countries could be energy self-sufficient and not depend on any imported energy sources.

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