Hydrogen as a clean energy source seems to be all the rage. That said, its detractors like to point out that it has been all the rage for decades, always offering more promise than actual results. But what are hydrogen fuel cells anyway? How can they be used? And why do those doubters never go away?
The Science
A hydrogen fuel cell, described in the absolute simplest form, combines hydrogen with oxygen to yield electricity and water vapor. Conceptually, such technology is highly appealing, as the input includes the most common element in the universe (hydrogen) and the second most abundant gas in Earth’s atmosphere (oxygen). Furthermore, the process of electricity generation yields a much more desirable byproduct (water vapor) compared to greenhouse gases.
Uses
Electricity generated by hydrogen fuel cells can be used to power electric motors in a wide variety of entities. Examples include cars, trucks, drones, forklifts, etc. In fact, many forklifts used in warehouses operated by companies like Amazon and Walmart are already powered by hydrogen fuel cells. Hydrogen-powered vehicles may ultimately find a niche in transportation due to their long range and short refueling times. These attributes compare well to battery-powered vehicles for which short range and long recharging times have been a concern. As such, the application of fuel cell technology to long-haul trucking that typically relies on diesel is in the works, occasionally earning hydrogen the label of the “next diesel.”
Criticism
Critics continue to have a fair amount of ammunition for several reasons, which include but are not limited to the following:
- Although hydrogen is remarkably abundant, it exists in complex with other elements, necessitating a process to create pure hydrogen from another source. One such source is natural gas, the extraction of which can directly release small amounts of methane, a potent greenhouse gas, into the atmosphere via leaks in the process. Similarly, producing pure hydrogen from natural gas releases carbon dioxide, another greenhouse gas. In other words, if the pathway to a clean energy source still includes a traditional energy source, the overall purpose of clean energy may be defeated. Sourcing hydrogen from water (via a process called electrolysis) or solar panel installations may circumvent this barrier.
- Hydrogen is highly flammable, increasing the chance of explosion with high heat exposures.
- At all points of the hydrogen energy life cycle (generation, fuel cell manufacturing, distribution, etc.), high cost remains a concern. Obviously, such a barrier could diminish over time.
Hydrogen will clearly have some role in the clean energy economy. It’s exact slice of the pie is what remains to be determined.
