Hydrogen Fuel for the Airlines

The airlines come under fire for the jet engine’s major contribution to carbon emissions, tagging passenger travel and shipment of goods and food products as contributing also to global warming.

This sudden attention to environmental issues becomes a competitive concern to air carriers. Airline manufacturers, primarily Boeing and Airbus, traditional arch enemies and competitors, find it beneficial to pool their R&D, addressing the possibilities of non polluting energy sources and potentially greater economy of energy use.

Furthermore, it goes without saying that completely abandoning petroleum as a source of energy eliminates the terrorist’s source of funding and deflates their will and their reason for conflict. --- Let them ride camels!

Historically, man started burning wood, dung, coal and then at the turn of the century oil and natural gas. Abandoning coal for natural gas was the big environmental issue in the 30s. It was not the brown cloud, but the black clouds that darkened the sky and lead to dirty black rain. Technology drove the evolution of energy then as now, but more significantly efficiency and economy drove the technology. Natural gas, methane, far exceeds coal in efficiency.

Chemists call the thermodynamics of chemical reactions, enthalpy. The Handbook of Chemistry & Physics lists the enthalpy of most of the energy producing chemical reactions. Simply put the chemical energy resides in the atom, and the scale of that energy source looks much like the periodic table with the highest energy contained in Hydrogen and Lithium and with much lower levels ranging in between. (Helium and Deuterium may not be far behind, once we go nuclear)[1]

As energy sources evolved, engineers looked in the direction of higher and higher portions of hydrogen in the molecule or mixture of molecules. Thus from coal to natural gas, the ratio of hydrogen to carbon increases dramatically. Even the subtle advance from propane to methane exhibits this progression: C3H8 to CH4 --- from 8:3 to 4:1.
From the perspective of the environment, (issues of greenhouse gas, global warming, rising levels of carbon dioxide and lowering levels of oxygen) oxidizing pure hydrogen, with a residual of pure water, achieves the greatest energy yield short of going nuclear. (Watch out for icy roads)

Interesting enough, Lithium the next best thing from a thermodynamic perspective, makes rapid advances as an energy source in cell phone batteries. Lithium’s light weight and less demanding storage, even it’s stability as a light metal gives it some advantage competing for the current energy of choice. The Tesla, a sports car, built on a Lotus chaise, utilizes some six thousand cell phone batteries as its energy source. The performance sounds spectacular. Hydrogen, utilized in a fuel cell in a sense acts as a battery, so in the all electric competition, hydrogen and lithium compete.

The airlines and the military, with their high volume kerosene burners, desperately need increasing efficiencies. Both economic and military necessity, drive aggressive aviation research. Economy, competition, and efficiency motivate change. Boeing and NASA drive this search for efficiency with aerodynamic changes and new fuels. Hydrogen may not be the ultimate aviation fuel but it is zero-emissions and it is very light. With minimal conversions it could burn in conventional jet engines. Hydrogen is the most abundant element on Earth, but there is as yet no infrastructure for its distribution. Cost and safety intervene. Liquid hydrogen provides three times the energy of kerosene, weight for weight, but maintaining it in a liquid state requires yet more energy, heavy tanks and refrigeration units.

Nuclear applications may be closer than we think. Certainly not fission with its radioactive waste and cold fusion may not happen, but a Princeton laboratory recently demonstrated fusion in a table top experiment on a nano scale.[2] Helium may be the critical energy source material in the future.1 If so, the extreme low volatility point as with hydrogen may be a challenge as will be its source on the Moon.

Gerald Brown, a physicist at NASA Glen Research Center in Cleveland suggests an all electric drive for aircraft utilizing super-conducting technology made possible by the extreme cold of liquid hydrogen and a low orbital environment. Such would be far more efficient than merely burning hydrogen in today’s turbofans.[3]

If the fuel cell-electric drive yields ice crystals or water at these altitudes, the system achieves all the more energy efficiency![4]

A small business construction entrepreneur (Dickey Gregoire) at the local coffee table suggested that, “Where there is confusion, there is money to be made.” That assertion may well apply to the Carbon issue. The disruptive technology puts old world thinking to bed and introduces new economic opportunity. “We have a lot of creative people with a lot of great ideas. Boeing’s Glover says, “Nothing’s off the table.”

Aviation may well lead the R&D and prove out a product, but it will be the auto industry that generates enough mass production to make it an egalitarian commodity for the people. It may well be that big oil holds less of a sway over aviation than it does over the auto industry, but once aviation breaks with the old paradigm, economics may win out. The efficiencies that a hydrogen economy promises make for a higher standard of living and a sustainable environment for us all.

[1] The Artemis Project ; http://www.asi.org/
[2] http://en.wikipedia.org/wiki/Crystal_fusion
[3] Nature 448 p120 12 July 2007
[4] Much of the efficiency loss in an internal combustion engine results from the energy taken up by the conversion of water to steam in the combustion and in the exhaust.