Electrolyzer and Hydrogen Fuel Cell Safety

Mar 14, 2023 | Electrolyzer, Green Energy

Electrolyzers and fuel cells are critical components of green energy systems as they enable the efficient storage and utilization of renewable energy. Electrolyzers allow for the conversion of excess renewable energy, such as wind or solar power, into hydrogen gas through electrolysis. This hydrogen gas can then be stored for later use or used directly in fuel cells to generate electricity. 

On the other hand, fuel cells produce electricity through a chemical reaction between hydrogen and oxygen, emitting only water vapor as a byproduct. By utilizing renewable energy sources and producing no harmful emissions, fuel cells and electrolyzers play a vital role in reducing greenhouse gas emissions and combating climate change.

Electrolyzers and fuel cells are often used together in green energy systems to create an efficient closed-loop cycle. Renewable energy sources such as wind and solar power generate electricity, which can be used to power electrolyzers that produce hydrogen gas. This hydrogen can then be fed into a fuel cell to generate electricity. The electricity generated by fuel cells can then be used to power homes, businesses, and vehicles, creating a sustainable energy ecosystem. This closed-loop system ensures that excess renewable energy is not wasted and that the energy generated is stored and utilized efficiently, reducing reliance on non-renewable energy sources and reducing overall greenhouse gas emissions.

Electrolyzers and fuel cells are exciting technologies that play an important role in the green energy economy. However, there are dangers associated with testing and operating these units, which must be addressed if the systems are to gain widespread adoption. In this blog post, we will provide critical insights into electrolyzer and fuel cell safety concerns.

Electrolyzer Fuel Cell Safety

An electrolyzer is a device that uses electrical energy to split water molecules into hydrogen and oxygen gasses. The process is called electrolysis and involves passing an electric current through a water-based solution that contains dissolved electrolytes, typically sodium or potassium hydroxide.

The electrolyzer consists of two electrodes, an anode and a cathode, which are separated by an electrolyte-filled chamber. When an electric current is applied to the electrodes, the water molecules in the electrolyte solution are split into hydrogen gas at the cathode and oxygen gas at the anode. The hydrogen gas is collected and stored for later use as a fuel source, while the oxygen gas is typically released into the atmosphere.

The following equation can represent the chemical reaction during electrolysis:

2H2O + Electrical Energy → 2H2 + O2

This reaction shows that two water molecules (H2O) are converted into two molecules of hydrogen gas (H2) and one molecule of oxygen gas (O2) through the application of electrical energy.

Graphic showing the reaction of 2H2O + electrical energy → 2H2 + O2 visually. 

Electrolyzer Safety Concerns

Testing a hydrogen electrolyzer can be hazardous due to the potential risks associated with hydrogen gas, electricity, and high-pressure systems. Some dangers associated with testing a hydrogen electrolyzer include:

  1. Fire and explosion hazards: Hydrogen gas is highly flammable and combustible and can easily ignite if it comes into contact with a spark or heat source. This can result in a fire or explosion, which can cause severe injury or property damage.
  2. Electrical hazards: Electrolyzers use electric current to split water into hydrogen and oxygen gas. If the electrical system is not properly grounded or insulated, it can pose a risk of electrical shock or electrocution to anyone working on or near the electrolyzer.
  3. Pressure hazards: Electrolyzers typically operate at high pressure to increase the efficiency of hydrogen gas production. If the pressure system is not properly designed or maintained, it can pose a risk of rupture or explosion, which can cause severe injury or property damage.
  4. Chemical hazards: The electrolysis process can produce harmful chemicals, such as chlorine gas, if the water used is contaminated with impurities. Exposure to these chemicals can cause respiratory problems, skin irritation, and other health issues.
Machine enclosure made with polycarbonate for pressure testing procedures.

To minimize the risks associated with testing a hydrogen electrolyzer, rigorous safety protocols and procedures are required, including proper ventilation, personal protective equipment, and adequate training. All electrical and pressure systems should be properly designed, installed, and maintained to prevent accidents or failures. Additionally, it’s important to conduct testing in a well-ventilated area away from other flammable or combustible materials.

TotalShield has decades of experience designing electrolyzer safety and containment systems and extensive testing data associated with electrolyzer failure analysis. For example, we detail our process to design safety enclosures for sodium hypochlorite electrolyzers here

Hydrogen Storage Safety

Once hydrogen gas is generated by the electrolyzer, it typically needs to be stored in a storage tank before being consumed in a fuel cell. Hydrogen gas is a promising energy carrier that has the potential to play a significant role in the transition to clean and renewable energy. However, one of the biggest challenges facing the widespread adoption of hydrogen fuel cells is the safe and efficient storage of hydrogen gas. Hydrogen gas is a highly flammable and volatile substance that must be stored at high pressures or low temperatures to ma

There are several hydrogen storage methods, including compressed gas storage, cryogenic storage, and chemical storage. Compressed gas storage involves compressing the gas to high pressures, typically around 350-700 bar, in a specially designed tank. Cryogenic storage consists of cooling the gas to extremely low temperatures, around -253°C, to liquefy it and store it in a thermally insulated tank. Chemical storage involves storing hydrogen in a solid state using chemical reactions, such as the reaction between hydrogen and metal hydrides. Each of these methods has its own advantages and disadvantages in terms of cost, efficiency, and safety.

Graphic showing how a hydrogen tank works.

Testing a hydrogen gas storage tank is a critical step in ensuring the safe and efficient use of hydrogen gas as an energy source. The testing process typically involves subjecting the tank to various environmental and performance tests to ensure its structural integrity, leak tightness, and resistance to extreme temperatures and pressures. The tank must also undergo rigorous safety testing to ensure that it can withstand impacts, fires, and other potential hazards.

One common testing method is hydrostatic testing, which involves filling the tank with water and subjecting it to a high-pressure test to check for leaks and assess its structural integrity.

Pneumatic testing is another common method for testing the integrity of a hydrogen storage tank. This involves pressuring the tank with a gas, typically nitrogen, to a specified pressure level and monitoring for leaks or failures. Here are the general steps for pneumatically testing a hydrogen storage tank:

  1. Preparation: Ensure the tank is empty and cleaned of debris or contaminants. The tank should also be properly grounded to prevent any static electricity buildup.
  2. Pressurization: Connect a pressure gauge and pressure relief valve to the tank and gradually pressurize it with nitrogen to the specified test pressure level. The pressure should be maintained for a specific period, typically between 30 minutes to several hours.
  3. Monitoring: Monitor the pressure gauge and observe for any pressure drops or fluctuations. Any significant pressure drops could indicate a leak or failure in the tank.
  4. Evaluation: After the pressure has been maintained for the specified time period, slowly release the pressure and inspect the tank for any visible signs of damage or leakage. The tank may need to be repaired or replaced if any issues are identified.

Pneumatic testing can be very dangerous. The risks associated with pneumatic testing are much more significant than in a hydrostatic scenario. Like hydrostatic testing, there is the threat that an object will be ejected ballistically during the test process. There is also a risk of explosive blasts. Put simply, an object under pneumatic pressure becomes a bomb, and at higher pressures, the explosive energies associated with a failure can be catastrophic.

At TotalShield, we have decades of experience designing safety enclosures and shielding rooms to protect staff during hydrostatic and pneumatic testing of pressure tanks. Read our blog post if you would like to know more about how to conduct these tests safely

Shielded enclosure for pneumatic testing. 

Hydrogen Fuel Cell Safety

When hydrogen is supplied to the fuel cell’s anode, it is split into protons and electrons. The protons pass through the electrolyte, while the electrons are forced through an external circuit, generating an electric current. At the cathode, oxygen from the air combines with the protons and electrons to form water, which is the only byproduct of the reaction.

Hydrogen fuel cells have several advantages over traditional combustion engines. They are more efficient, producing electricity up to twice the efficiency of internal combustion engines. They are also cleaner, producing only water as a byproduct, and can be powered by renewable sources of hydrogen, such as electrolysis of water using electricity generated from solar, wind, or hydroelectric power.

However, the testing and development of hydrogen fuel cells come with a number of hazards that must be considered and addressed.

Graphic showing how a hydrogen fuel cell works.

One of the most significant is the risk of explosion during pneumatic testing. Pneumatic testing is a crucial part of the development process of hydrogen fuel cells. It involves pressurizing the fuel cell to ensure it can withstand the pressure generated during normal operation. However, this pressurization can also create a risk of explosion if not properly managed. 

The risk of explosion during pneumatic testing is primarily due to the flammability of hydrogen. As hydrogen is highly flammable and can ignite easily, it is important to minimize the risk of leaks during testing. This can be done by properly sealing the fuel cell and ensuring that all connections and hoses are secure. It is also crucial to monitor the fuel cell for leaks during testing and to take appropriate action if a leak is detected.

Another factor contributing to the explosion risk during pneumatic testing is the hydrogen pressure within the fuel cell. The fuel cell can rupture if the pressure exceeds the design specifications, or if the fuel cell has an imperfection or defect. There are three dangers associated with a rupture:

  1. The ruptured fuel cell can expel fittings, metal fragments, gauges, or other components and create a ballistic hazard to bystanders
  2. The rapid release of pressure can itself cause a danger to operators in the form of a pressure wave
  3. Hydrogen gas can ignite and cause an explosive fireball

TotalShield manufactures shield enclosures and shield rooms, which can protect from the ballistic, explosive, and fire risks associated with a fuel cell rupture during testing or in an operational setting. Our products are engineered and sized based on the size and volume of the fuel cell to ensure a safe environment for anyone working in the area of the fuel cell.

It is also crucial to have proper ventilation in place in the event of a fuel cell failure. Hydrogen gas is in itself not toxic, but it can displace oxygen and cause suffocation. It is critical to have proper ventilation in any area where fuel cells are tested or operated. Because hydrogen is colorless and odorless, an oxygen sensor can provide a warning when levels get too low. Our electrolyzer enclosures can be configured with fans and vents to ensure adequate ventilation. In addition, our flexible framing system can accommodate fire suppression, monitoring and alarms, lighting, and other safety features in a straightforward “bolt-on” fashion.

It is also important to ensure that emergency procedures are in place in the event of an explosion, including evacuation plans and the availability of fire extinguishers and other safety equipment.

Electrolyzer polycarbonate clear shielded enclosure render manufactured by TotalShield.

In conclusion, electrolyzers, hydrogen storage tanks, and fuel cells are vital components in the move toward a more sustainable green-energy economy. However, they each pose unique risks in testing and operation that need to be carefully considered to ensure safety. If you would like to chat about your green energy safety needs, please contact the experts at TotalShield and we will be happy to help! 

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