Hydrogen fuel cells for automotive use are one of those "great in theory, flawed in principal" ideas for the future of car propulsion. New technology using bacteria could eventually change that.
Fuel cells have several advantages over pure battery-electric power, for example. Firstly, hydrogen has greater energy density than the average battery, so you can drive for longer on the electricity generated by the fuel cell. It's also much quicker to fill a tank of compressed hydrogen than it is to wait for a battery to charge.
Emissions are low too - typically, only water drips out of the tailpipe, and because they don't need charging from the mains, there's no power plant pollution to worry about. Then you have all the usual electric car advantages such as quiet and smooth running and the adaptability of not having to assign a set place for a fuel tank, engine and transmission.
Unfortunately, hydrogen is expensive and difficult to produce in meaningful quantities, and incredibly energy intensive to produce too - to the point where you use more energy to extract hydrogen from the easiest method, electrolysis of water, than you get from it as a fuel.Limitless hydrogen from bacteria
Ideally, what you need is a way to produce hydrogen with minimal energy input. Bacteria could be the answer.The BBC has reported on a team of U.S. researchers
who have demonstrated a fuel cell powered by bacteria that produce a limitless supply of hydrogen. Production of the hydrogen works on a very similar principal to that of current electrolysis technology, but the bacteria replaces the electrodes. Certain strains of bacteria produce a stream of electrons as a by-product of breaking down organic matter.
Co-author of the research, Professor Bruce Logan from Pennsylvania State University, explains: "We use those microbes, particularly inside something called a microbial fuel cell (MFC), to generate electrical power.
"They produce this electrical current, which are electrons, they release protons in the water and these combine with electrons".
This means an electrical power source - and large amounts of electrical energy - are no longer needed to power the electrolysis, and bubbles of hydrogen and oxygen are produced from the electrical charge passing through the water from the bacteria.
The team admits the technology is in its infancy for the time being, and it's certainly not cheap at the moment either. Prof. Logan likens the technology to solar power, which has taken many years to develop and reduce in cost.
Could it be used to power fuel cells in cars like the Honda FCX Clarity
? Time will tell. For the time being, the researchers are working on developing larger cells to test the viability of such a system.