Energy storage is an essential part of the pursuit for the increased use of renewable energy sources such as wind, solar, geothermal and hydroelectric power. Electrolyzers allow hydrogen-based storage and avoid the reliance on batteries and their raw materials such as lithium, graphite and cobalt that are frequently sourced from China. When renewable energy sources provide the input for electrolyzers, the hydrogen produced is called green hydrogen. With a green hydrogen boom underway, electrolyzer sales doubled in 2022 and could triple in 2023 according to BloombergNEF.
A variety of options exist for producing renewable hydrogen and electricity. Source: Renewable Electrolysis | Hydrogen and Fuel Cells | NREL
An electrolyzer uses electricity in a process called electrolysis to split water into hydrogen and oxygen and fuel cells convert the hydrogen back to electricity. Both electrolyzers and fuel cells are made by stacking multiple anode and cathode plates and a membrane between each and tie-rods hold them in place. Different electrolyzers function in different ways, mainly due to the different types of electrolyte material involved.
A basic electrolyzer stack. Source: Hydrogen Production: Electrolysis | Department of Energy
The three main types of electrolyzer technologies used to produce green hydrogen include: (1) alkaline (alkaline electrolysis (AEL) or alkaline water electrolysis (AWE)), (2) proton-exchange-membrane or polymer-electrolyte-membrane (PEM) and (3) solid-oxide electrolyzers (SOEL). Each technology has its own advantages and disadvantages.
Operated by the Alliance for Sustainable Energy LLC, the National Renewable Energy Laboratory (NREL), a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, conducts renewable electrolysis research that focuses on designing, developing, and testing advanced experimental and analytical methods to improve electrolyzer stack and system efficiency. This national lab as well as other organizations are investigating ways to increase the production of green hydrogen and lower the cost of producing it.
“Regardless of the technology used for the electrolyzer, sensors will be essential for monitoring and maintaining the ongoing green hydrogen process,” says Brian Peters, Global Vice President, Interface Inc., a world leader in force measurement solutions.
The power companies using electrolyzers for producing hydrogen will need to create and maintain a real-time monitoring system to measure the tension of the tie rods to ensure heightened productivity, such as:
- Avoiding unnecessary costly preventive maintenance
- Preventing shutdowns
A load cell-based system to monitor the tension in the bolts of tightened tie rods.
Using a stainless-steel precision load washer load cell, such as an Interface LWHP14, a load cell monitoring system successfully monitors the tie-rods tension in real time and avoids unnecessary costly preventive maintenance and unplanned shutdowns of the electrolyzer.
The system consists of a load cell installed under the bolt of a tightened tie-rod around the electrolyzer. Connected to transmitter module, which is encased in a junction box, each load cell measures the compression forces from the tightened tie-rod and the results are transmitted to a wireless telemetry dongle base station connected to the customer’s PC. Each load cell can be monitored in real time using available software.
In addition to load cells, other sensing technologies, such as chemical, temperature and pressure sensors, will also be required for the safe and cost-effective means of producing and storing green hydrogen. For example, hydrogen can be stored physically as either a gas or a liquid. Storage of hydrogen as a gas typically requires high-pressure tanks with 350–700 bar [5,000–10,000 psi] tank pressure. If a hydrogen leak occurs, a hydrogen chemical sensor can detect the leak and prevent a hazardous situation.