Energy Day and Night from Solar/Fuel Cell Combination

August 4, 2008 in environment, green chemistry, science, science and society, sustainability
Tags: alternative energy, catalyst for electrolysis, electrolysis, ExtremeTech, fuel cells, fuel cells vs. batteries, GoodCleanTech, hydrogen economy, hydrogen gas, MIT, oxygen gas, solar cells, storing energy

Originally published in a somewhat different form on my Squidoo solar power lens and Sustainability group. Please note that Sam Carana has written a lot about the hydrogen economy, and he covered this same story, but with more technical information about the new science and catalysts, here.

Hydrogen and oxygen gases can be used in fuel cell technology to provide energy to a home, and these gases can be produced by the action of electricity on water. Hydrolysis can also be carried out by the action of sunlight on water, with the help of certain types of solar cells, or photovoltaics. Electrolysis often requires caustic conditions, or high pH (or a lot of electricity is wasted), but the caustic requirements, and most wasted electricity, can be overcome with the use of additional components known as catalysts. The result is that solar energy can be used to power a home during the day by generating electricity, and consumers would have a variety of options to store excess electricity:

Batteries are typically thought of for storage of electricity, but another option is offered by the power of sunlight: energy storage through generation of hydrogen and oxygen by electrolysis. Gernation of hydrogen and oxygen under acceptable and convenient conditions has become just more possible with the discovery of a new, breakthrough catalyst for electrolysis:

As described by Mariella Moon of ExtremeTech, “… one catalyst would be responsible for producing oxygen gas from water, while another would produce hydrogen. The hydrogen and oxygen could be recombined in a fuel cell to power the home at night where solar energy isn’t readily available…”

Hydrogen and oxygen would accumulate during the day from excess electricity generating capacity of a solar cell system, and then these gases would serve as the fuel for a fuel cell that would power a house overnight. The byproduct of the fuel cell, water, could then be re-used for water splitting (electrolysis) the next day.

Illustrations of the idea and video from principle scientist D. Nocera of MIT is shown at the GoodCleanTech site, the Green Blog of pcmag.com, as posted by Mariella Moon.

The key to the new catalyst for electrolysis is that, unlike the catalytic converter in your car, it does not require expensive metals like platinum or rhodium, yet it works at atmospheric pressure, room temperature and moderate pH, thus providing hydrogen and oxygen that can feed a fuel cell with minimal environmental impact.

Original text copyright © 2008 James K. Bashkin