Hydrogen is the lightest and most abundant element in the universe. That’s terrific news because, in both the present and the future, hydrogen is proving to be one of our greatest allies in developing green energy alternatives and combating climate change. Read more to understand hydrogen’s importance and how we can use it!
The Benefits and Importance of Hydrogen Fuel Cells
You’ve probably heard about hydrogen fuel cells before, either in a classroom setting, on the internet, or in the news. But what are they and how do they work? Before we get into that, let’s talk a little about what makes them so great.
Using hydrogen fuel cells to power the world around us comes with many benefits, both to us and our environment because:
One of the biggest applications of this technology that we’ve been seeing lately is hydrogen-powered cars, like the Toyota Mirai and the Hyundai Nexo. Considering the fact that sources of transportation (like cars, trucks, ships, trains, and planes) are one of the biggest contributors to greenhouse gas and carbon emissions that we release into the atmosphere, this is a step in the right direction and more important than ever. Scientists and engineers continue to work diligently on improving the cost, efficiency, and effectiveness of hydrogen-powered vehicles in order to make their further implementation a reality.
Sources of Hydrogen Gas
In order to run a hydrogen fuel cell, we first need to collect some of its fuel: hydrogen gas. By itself, pure hydrogen gas exists in a diatomic, gaseous form (H2). Because hydrogen gas in this form is so light, much of it simply rises into Earth’s upper atmosphere and eventually escapes into space. (It’s for this reason that hydrogen gas makes up a mere ~0.00005% of Earth’s atmosphere.) But fortunately for us, hydrogen exists in abundance on our planet in forms where it is “locked in” and combined with other elements, in molecules like water and hydrocarbons. There are three primary ways to extract hydrogen from such compounds:
Electrolysis: Creating Hydrogen Gas from Water
Today we’ll be focusing on the potentially greenest of the methods listed above: electrolysis. The process of electrolysis first begins by introducing water to a device called an “electrolyzer.” As the water molecules enter the device, a voltage is applied between the fuel cell’s anode and cathode using an external power source. This coaxes the molecules of water (H20) to split, forming hydrogen ions (H+, aka protons), electrons (e–), and diatomic molecules of oxygen gas (O2).
At this point, our hydrogen ions pass through a portion of the electrolyzer called a “proton exchange membrane,” or PEM for short. The electrons that were stripped from our hydrogen atoms go for a ride through the external power source mentioned previously. Our oxygen gas is now free to exit the electrolyzer, to be collected for later use or to simply be released into the atmosphere.
Once our hydrogen ions reach the other side of the PEM, entering the cathode region of the electrolyzer, they are gleefully reunited with their long-lost electrons, forming hydrogen gas that can be used to run a hydrogen fuel cell! The key thing to remember here is that we need to apply energy via our external power source to make this whole process of electrolysis occur. The greener that source of energy, the better.
Running a Hydrogen Fuel Cell
The process of running a hydrogen fuel cell is very similar to the process of electrolysis, just in reverse. In fact, many kinds of hydrogen fuel cells are designed to be “reversible fuel cells” that can function as both the electrolyzer and the fuel cell.
First, hydrogen gas is introduced to the anode of the fuel cell and splits to form hydrogen ions and electrons. The hydrogen ions pass through the PEM while the electrons pass through a circuit connecting the anode to the cathode. (The current generated by the flow of these electrons is what allows a hydrogen fuel cell to power something like a hydrogen-powered car!) On the other side of the PEM, in the cathode region of the fuel cell, our hydrogen ions, electrons, and oxygen gas react together to form clean, pure water. Behold, electricity from hydrogen!
Live In Action at ITEEA
If you’re interested in learning more about hydrogen fuel cells and are planning on attending this year’s annual ITEEA conference in Minneapolis, be sure to sign up for my April 12th workshop entitled “Exploring Renewable Energy and Hydrogen Fuel Cells with Project-Based Learning.” In this workshop, attendees will have the opportunity to create their own miniature, hydrogen-powered kart using recyclable materials and a small reversible hydrogen fuel cell! Participants will leave with their own functioning hydrogen-powered kart and some ideas for applications in the classroom.
If you can’t make it to ITEEA this year, no worries. In lieu of experiencing the magic of hydrogen fuel cells in person, you can always check out the Horizon Educational products featured on our website! These kits are a great way to immerse students into the world of renewable energy with hands-on, project-based learning in mind.
Until next time, folks.
– Dr. Jake Roark