Arun Micro > 2015 > September

Hydrogen Economics: Boom or Bust?

In the ongoing search for sustainable, reliable, inexpensive and environmentally friendly energy sources, hydrogen has long been a contender. It is the simplest and most abundant element in the universe. This abundance, and the fact that when burnt as fuel its only remnants are water and warm air, make it a very attractive option. However, the costs and complications surrounding the creation and storage of liquid hydrogen are still holding it back from becoming a dominant fuel source. Experimentation to find cheaper ways of tackling this problem is taking place all over the world.

Producing Hydrogen

Currently, there are a number of ways to produce liquid hydrogen but the processes are all energy-hungry, to the point where the amount of energy required to produce the hydrogen is similar to the amount of potential energy stored in it. Clearly, this is not economically viable in most applications. Problems arise because hydrogen does not typically exist in nature by itself and it is often the process of separating it from other materials, such as water, that takes up the most energy. The most common processes being used are:

  • Thermochemical Processes – Using heat and chemical reactions to release hydrogen from sources like water. Energy for this comes from fuel materials like natural gas, coal or bio-diesel.
  • Electrolysis – As this process can be used to produce hydrogen with no greenhouse gas emissions and using renewable energy sources, a great deal of experimentation is ongoing to discover how to use it in a cost effective way.

Many other methods are used and more are being developed all the time.

Using Hydrogen

Production costs are not the only issue preventing hydrogen being used as a financially viable fuel source. Making it into a usable form and storing it are also key factors due to the very low boiling point of hydrogen. Liquid Hydrogen has to be stored at around -253°C and be highly pressurised. Cooling and compressing it into this state is also an expensive and high energy consuming process.

However, NASA uses approximately 10 million pounds of liquid hydrogen a year. They favour hydrogen as the main fuel for space vehicles because it is very light and powerful as a rocket propellant. This is because it has the lowest molecular weight of any known substance and burns at around 3,000°C.

The Future

New methods of producing liquid hydrogen are being discovered all the time. These include: Direct Solar Water Splitting Processes which involve using light energy to split water into hydrogen and oxygen, as well as Biological Processes which use microbes to produce hydrogen through biological reactions. New production techniques, along with refinements to widely used processes, mean that cost effective hydrogen fuel production is coming closer and closer along with all the environmental benefits.

AML design and create equipment which can be used at cryogenic temperatures to aid in the type of experimentation which has the potential to make this use of hydrogen possible. For more information on their products, call 01903 884141 or email to find out what they can do for you and your research.

The History of Cryogenics

Scientists in the 19th Century started experimenting with very cold temperatures. This type of study was called cryogenics. Major experimentation in this area began when scientists such as Michael Faraday began to liquefy gasses. Throughout the century, scientists went on to develop more sophisticated methods to create increasingly colder temperatures - this led to scientists liquefying all the known permanent gasses and finding new properties of solid materials.

A brief history of cryogenics; the discoveries made and the methods used

  • 1845 – By this time Michael Faraday had liquefied most of the permanent gasses known at that time except oxygen, hydrogen, nitrogen, carbon monoxide, methane and nitric oxide.
    •  Method – Immersing the gas in a bath of dry ice and then pressurising it until it liquefied.
  • 1877 - Louis Cailletet in France and Raoul Pictet in Switzerland succeeded in creating droplets of liquid air.
    • Method – Cailletet dropped the temperature through rapid expansion of the gas. This was achieved by compressing the gas with mercury using a steel and glass apparatus, before draining the mercury away allowing the gas to expand.
  • 1898 – James Dewar liquefied hydrogen at the lowest temperature ever achieved at that point, -252.5°C. He went on to solidify it at -258°C.
    • Method – Using liquid air at -200°C he cooled the hydrogen before forcing it through a fine nozzle into a vacuum. It liquefied when it escaped from the nozzle.
  • 1908 - Heike Kamerlingh Onnes liquefied helium which has the lowest boiling point of any known substance at -268.9°C.
    • Method – He created four cooling cycles using different liquefied gasses including oxygen and hydrogen. The helium was cooled more and more at each stage.
  • 1911 - Kamerlingh Onnes also discovered that if certain metals are cooled to temperatures not far above absolute zero they lose any resistance to electrical currents. This is called superconductivity and has many applications in the modern world.

Cyrogenic Applications in the 21st Century

MRI scanners widely used in medicine across the world rely on cryogenics to create magnets powerful enough to operate effectively. In scientific research, the Large Hadron Collider at CERN, The European Organisation for Nuclear Research, uses incredibly powerful magnets kept at very low temperatures to accelerate particles. Cryogenic liquids are also used a great deal in space exploration.

Cryogenic experimentation has come an incredibly long way over the past 150 years but it is still ongoing and continuing to make important discoveries. AML makes stepper motors and other equipment which can be used to conduct experiments with and using cryogenic materials. Call 01903 884141 or email to find out what they can do for you and your research.