Often, when we think of electric power generators, we only envisage gas and diesel generators that run on fossil fuels. This isn’t an entirely bad thing, as fossil fuel generators are the most available. They are also the most straightforward to use.
However, consumers are increasingly aware of newer power generator technologies, such as biofuels and solar power generators. Another option on the list that could become very popular soon is – hydrogen generators.
Read on to learn how hydrogen generators work, the pros and cons, and whether a hydrogen generator would be the ideal investment to solve your power needs.
What’s a Hydrogen Generator?
Hydrogen generators, or hydrogen fuel generators, generate high purity hydrogen gas from various chemical processes. The hydrogen gas can then be harnessed to run electrical appliances, cars, and even extensive facilities.
The resulting hydrogen works more or less as natural gas. It can be delivered to fuel cells to generate electricity and heat or run an engine. Larger plants also use it in combined cycle gas turbines to generate large quantities of centrally produced electricity.
How it Works
The way hydrogen generators work, specifically to produce electricity for domestic and commercial use, is a little complex.
First off, you need to understand that, although it’s the most abundant element on earth and even considered the basic building block of the universe, hydrogen doesn’t exist naturally in large quantities. Instead, it’s primarily found in combination to form water, which covers 71% of the earth’s surface. Besides water, hydrogen is readily available in hydrocarbons, such as natural gas and propane, and domestic sources, such as biomass.
Thus, to obtain pure hydrogen, you need a secondary process. Currently, the most common ways to obtain pure hydrogen gas are through fossil fuel reforming (a thermal process) and electrolysis (a chemical process).
As of 2021, most of the available hydrogen is generated from fossil fuels by steam reforming or partial oxidation of methane and coal gasification. All three processes involve extracting hydrogen from the methane available in the mentioned fossil fuels.
Unfortunately, thermal processes that generate hydrogen gas are also very inefficient. Methane streaming releases significant quantities of fossil carbon dioxide and carbon monoxide. As a result, the process is used exclusively in large plans that produce massive amounts of industrial hydrogen.
Smaller power generators use the second option – electrolysis – to generate and store power for electricity production.
Hydrogen Electrolysis
Electrolysis is the process of splitting water into hydrogen and oxygen atoms. The process takes place in a special unit known as an electrolyzer – a device that operates pretty much like a fuel cell in reverse. Indeed, many small-scale hydrogen generator manufacturers, such as Cummins, use fuel cells to create hydrogen from water molecules.
Similar to the fuel cell, the electrolyzer comprises an anode and a cathode separated by an electrolyte. The way the unit produces hydrogen primarily depends on the type of electrolyte.
Currently, there are three broad electrolyzer categories;
1. PEM electrolyzers
Polymer Electrolyte Membrane (PEM) electrolyzers are the most common electrolyzers. They use solid specialty materials as electrolyzers. Water reacts at the anode when the electrolysis process starts, forming oxygen and positively charged hydrogen ions (protons). The electrons flow through the external circuit while the hydrogen ions cross over to the cathode, interacting with electrons to form hydrogen gas.
2. Alkaline electrolyzers
Alkaline electrolyzers operate slightly differently. They transport hydroxide ions to the cathode through the electrolyte, with hydrogen gas generated on the cathode. Most generators in this category use liquid alkaline solutions, especially sodium hydroxide or potassium hydroxide. However, we’re recently seen newer solutions that use Alkaline Exchange Membranes (AEMs).
3. Solid oxide electrolyzers
Finally, solid oxide electrolyzers use solid ceramic materials as the electrolyte. The ceramic material selectively conducts negatively charged oxygen ions at elevated temperatures to generate hydrogen atoms. Essentially, steam at the cathode interacts with electrons from the external circuit, forming hydrogen gas and oxygen ions. Then the negatively charged oxygen ions are forced through the ceramic membrane to the anode, gaining electrons to form oxygen gas.
Hydrogen Generator Advantages
Hydrogen power generators come with several advantages which have attracted attention from domestic and commercial users;
- It’s renewable
Hydrogen power is only comparable to sola when discussing renewability. It is the most abundant material on the earth’s surface and is continuously replenished through various natural activities, such as decay beneath the ground. Indeed, although it takes a little more effort to harness, no other energy source is as infinite. Thus, the world can never run out of hydrogen.
- Multiple sources
We’ve focused mainly on electrolysis in this guide because it’s considered the cleanest way to generate hydrogen for power generation. However, there are many other sources of hydrogen that you can use to generate electricity. These include methane (also very popular), gasoline, biomass, and coal. Some processes, such as photobiological, photochemical, and thermochemical processes, even use solar energy to generate hydrogen. The choice is yours.
- It’s a clean energy source
Unlike diesel engine generators and other fossil fuel generators that produce tons of carbon monoxide and other greenhouse gases during combustion, hydrogen is very clean. Some hydrogen production systems are so efficient the only byproducts are oxygen atoms and water. For instance, astronauts, who use hydrogen to power their rockets, convert the “burnt” oxygen into drinking water.
- It is a highly potent power source
Hydrogen burns so efficiently, converting nearly all the base material, such as water in the electrolysis process, into useful energy. This allows it to produce a lot more electricity (watts) per unit of fuel compared to other generator types. Another way to say this is that a hydrogen power generator will run much longer than gasoline and other generators, assuming equal fuel quantity.
Hydrogen Generator Downsides
While hydrogen generators have endless benefits, they may not be the right power source for everyone and every application. Here’s why;
- Hydrogen energy is expensive
If you think diesel is expensive, you haven’t met hydrogen gas. According to the Department of Energy, it costs about $6 to produce a kilogram of hydrogen gas through PEM electrolysis. This is enough to generate about 33.6 kWh of usable energy. Given that you need about two kilos of diesel (@14kWh) to generate the same amount of electricity, and diesel costs $(3.3/3 = 1.1)/kg, you can see that you need only about $2.2 to produce the same electricity as $6 worth of hydrogen gas.
- Storage complications
The other major issue is storage. Hydrogen has a lower density than gasoline, meaning that you must first compress it to liquid before storing the fuel. You also need to store it at very low temperatures. This explains why hydrogen is always stored and transported under high pressure. This makes everyday use of hydrogen generators a little complicated.
- It comes with a few safety issues
Granted, hydrogen is safer than most fossil fuels, including diesel and gas. However, this doesn’t mean that hydrogen generators are entirely safe. For one, hydrogen is a highly flammable and volatile substance that can catch fire without warning. Worse still, unlike the other fossil fuels, hydrogen lacks smell, making it nearly impossible to detect leaks without a sensor. Combine the two issues, and you have a ticking time bomb.
What to Look for in a Hydrogen Generator
If, despite the challenges, you still feel that a hydrogen power generator would be the best solution for your power issues, we recommend that you consider the following factors to identify the most suitable unit.
- Buy a specialized model
Hydrogen power generators come in many different shapes and options. To avoid potential costly risks, go with one designed specifically for electric power generation. Fortunately, several manufacturers now make safe-to-use portable electrolyzers that you can use at home to produce electricity.
- Purity levels
The best hydrogen generators can extract maximum hydrogen atoms from the base material (water, gas, diesel, biomass, etc.). The good news is that some generators are up to 99.99% efficient, meaning they guarantee maximum value for your bucks.
- Your power demands
How much power do you want from the hydrogen generator? This will depend on the intended application. For instance, if you’re putting up a backup power system for your garage, you may need up to 1000 watts. Using this information, shop around to find a generator that can deliver 1,000 watts or slightly more.
- Portability
Hydrogen generators can be portable or permanently installed, depending on the size. Smaller units are typically portable. You can bring it inside at night and out in the morning. Meanwhile, larger ones are installed permanently at a selected location. If it’s portable, make sure it’s easy to handle, i.e., carry and move around. However, if it’s permanently installed, choose a good location and ensure it’s professionally installed.
Summary
Hydrogen generators are another excellent source of electric power. They are highly efficient, and water-based electrolysis models are extremely clean energy sources that only produce water and oxygen upon combustion. The only challenge is the high initial costs and slightly high running costs. If you’re prepared to pay slightly more for clean energy, we’d say it’s one of the best power solutions.
