Friday, September 4, 2015

The Hydrogen Economy

Spectron telescope of hydrogen in the Orion Nebula

If we apply a perversion of Occam's razor to the problem of global warning made worse by increasing demands for energy, we are left with the simplest of fuels – natures most abundant and simplest element – hydrogen. All of the burning of fossil fuels is really a way to burn hydrogen. But using hydrocarbons burns the hydrogen while producing large amounts of CO2. What if we could burn the hydrogen in its pure form? It turns out we can. And the byproduct is simply water. We have been doing it since fuel cells were first invented back in 1839 by Sir William Grove.  It's such a good idea that NASA has been using it for years to provide both water and power on space missions.


Schematic of a fuel cell showing H on one side of the cell, and water on the other
A fuel cell is a device consisting of a gas diffusion electrode comprising a catalyst that separates hydrogen atoms into their component parts, a proton and an electron. The protons traverse an exchange membrane and travel through another diffusion electrode, while the electrons are used to power something. In the above illustration, they power a light bulb, while in a car they power an electric motor. After this they are reunited into hydrogen atoms, which combine with the oxygen in the air to produce water. All that is needed for this to happen is a continuous supply of hydrogen gas. Boeing has a drone that is powered by a fuel cell with hydrogen produced by a solar array that electrolyzes water. The California Fuel Cell Cooperative has even established hydrogen refueling stations to service cars that are powered by fuel cells.

Hydrogen fuel cap on a fuel cell powered car
Chevrolet, Ford, Toyota, Hyundai, VW,  and Honda all have fuel cell cars in production and planning stages.

Maine has an economic and environmental interest in the hydrogen economy. At The Hydrogen Energy Center in Portland, ME,  in addition to hydrogen and fuel cell applications for transportation, they are exploring hydrogen as a storage medium for intermittent energy sources, hydrogen fuel cells for combined heat and power, and hydrogen applications in the pulp and paper industry. According to their web site, "When a renewable, economically viable production process of hydrogen can be achieved the advantages will spread out to many industries. Some of the proving grounds for various production methods can be locally developed to provide hydrogen for these industries."

The difficulty all along has been the technology required to obtain and store hydrogen.
Current methods rely on electrolysis of water which separates the water into its two components, hydrogen and oxygen. While Elon musk, the founder of Tesla, an electric car company, has put down the concept of hydrogen in favor of his electric, battery-powered cars, those cars are charged with electricity produced by carbon based fuels.

Tesla Motor Company's Tesla 2X
If this exciting hydrogen-as-fuel concept becomes widespread, that problem will be eliminated because large hydrogen burning power plants will replace the current hydrocarbon-based approach. This means that electric cars can be more efficiently charged using electricity produced by hydrogen-based power plants. Still, recharging takes a significant amount of time. Eventually, motors in today's electric cars may be powered by fuel cells. In either case one of the least desirable aspects of living in large cities, toxic smog, will be eliminated. If all the vehicles and all the heating plants in large metropolitan areas were burning hydrogen, there would be virtually no pollutants in the air. The byproduct of burning hydrogen is simply water. The byproduct of separating water from the hydrogen is extra oxygen either being stored for commercial use or simply released into the atmosphere.

Recent breakthroughs involving catalysts and very small amounts of electricity are yielding exciting results. There is even a plastic credit-card-like substance that, immersed in water and exposed to sunlight, causes this breakdown of water into its constituent elements. It's called an artificial leaf.

Testing a 1 cm x 1 cm artificial leaf.
This is an exciting prospect because it has the potential for providing small home sized power systems in Third World countries as well as in developing nations, without the dangerous burning of carbon-based fuel. It even  produces potable water.

Many aspects of the future use of hydrogen as fuel are already in place. Many are being developed. All are on a fast track to reality, along with as yet undiscovered and unexplored means of making and storing this amazing and useful element. A good thing, too, because, while Elon Musk may be wrong about hydrogen as fuel for cars, he's right about the need for responsible uses of our planet's resources. If we do nothing, we're headed for disaster.

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